Quiet only the stdout UI under --json, not the log level (closes #112)

--json was folded into Quiet, which pinned the stderr log level to WARN.
So `prune --json` gave a machine consumer no record of the local index
rows it deleted, even under --verbose: the audit records were gated off
stdout and pinned below the level on stderr.

--json now quiets only the stdout UI, keeping the JSON document clean
(issue #108); the stderr log level follows --verbose/--debug again, since
diagnostics have gone to stderr since #82. The same coupling is removed
for `snapshot verify`, `snapshot remove`, and `remote info`, which
carried it for the same outdated reason.

A test asserts `--verbose prune --json` emits the cleanup record on
stderr while stdout stays exactly one document, and that --json alone
keeps it below the level.

model: claude-opus-4-8

Dockerfile.lint

@@ -72,11 +72,11 @@ RUN [ -n "$CHECK_EPOCH" ] || exit 1
 # running, and exits 0 reporting `0 issues.` on a tree the real config
 # fails. Demonstrated on this repo at this pin, recorded on
 # https://git.eeqj.de/sneak/vaultik/pulls/114: with a planted
-# over-length line, `script/lint` exits 1 naming the `lll` finding with
-# `linters:` and exits 0 with `linterz:`. A set-but-ineffective config
-# quietly falling back to defaults is precisely the false-green class
-# this gate exists to eliminate, so it must not sit in the gate's own
-# configuration.
+# over-length line, `script/lint` exits 1 naming the `revive` finding
+# with `linters:` and exits 0 with `linterz:`. A set-but-ineffective
+# config quietly falling back to defaults is precisely the false-green
+# class this gate exists to eliminate, so it must not sit in the gate's
+# own configuration.
 #
 # `config verify` catches it, and it does so OFFLINE at this pinned
 # version -- verified, not assumed. Under `docker run --network none`

README.md

@@ -251,7 +251,8 @@ local index alone, and still exits zero.
 per-snapshot-name (`--keep-latest` keeps the latest of each name, not the
 latest globally).
 * `--keep-latest`: Keep only the most recent snapshot of each name
-* `--older-than <duration>`: Remove snapshots older than duration (e.g. `30d`, `6m`, `1y`)
+* `--older-than <duration>`: Remove snapshots older than duration (e.g. `30d`,
+  `4w`, `6mo`, `1y`; `m` is minutes, `mo` is months)
 * `--snapshot <name>`: Restrict to specific snapshot names (repeat for multiple)
 * `--force`: Skip confirmation prompt
 

TODO.md

@@ -35,6 +35,35 @@ release" is exactly the contradiction
   no `--json` representation — under `--json` the summary is suppressed
   entirely — so nothing there can show a false `0`.
 
+- 2026-09-21: Stopped `--json` from silencing stderr diagnostics
+  ([issue #112](https://git.eeqj.de/sneak/vaultik/issues/112)). `--json`
+  used to be folded into `Quiet`, which pinned the log level to `WARN`,
+  so `prune --json` gave a machine consumer no record of the local index
+  rows it deleted even under `--verbose`. `--json` now quiets only the
+  stdout UI (the JSON document must stay clean, per
+  [issue #108](https://git.eeqj.de/sneak/vaultik/issues/108)); the stderr
+  log level follows `--verbose`/`--debug` again. The coupling was
+  removed the same way for `snapshot verify`, `snapshot remove`, and
+  `remote info`, which carried it for the same outdated reason.
+
+- 2026-09-21: Made the s3 storage backend report a missing object as
+  `storage.ErrNotFound`, like the `file` and `rclone` backends and as the
+  `Storer` interface documents. `S3Storer.Get` and `Stat` returned the raw
+  AWS SDK error, so `errors.Is(err, storage.ErrNotFound)` was false on s3
+  and callers branched differently per backend. Added a small `s3.IsNotFound`
+  helper (reused by `HeadObject`) and a test that a missing key maps to
+  `ErrNotFound`
+  ([issue #129](https://git.eeqj.de/sneak/vaultik/issues/129)).
+- 2026-09-21: Fixed `verify --deep` reporting healthy snapshots as
+  corrupt. Its final blob-integrity check hashed the encrypted
+  downloaded bytes with a single SHA256 and compared that to the blob
+  ID, which is the double SHA256 of the plaintext, so the two could
+  never match. It now hashes the decompressed plaintext and compares the
+  double SHA256. Added a test that backs up a real snapshot, deep-verifies
+  it, then flips a byte in one stored blob and confirms deep verification
+  then fails
+  ([issue #131](https://git.eeqj.de/sneak/vaultik/issues/131)).
+
 - 2026-09-21: Made `snapshot create` VACUUM the per-snapshot metadata
   database through the `modernc.org/sqlite` driver instead of shelling
   out to the external `sqlite` command-line binary (issue #120). A
@@ -60,6 +89,24 @@ release" is exactly the contradiction
   keeps that exact compiler from auto-switching. Bumping Go now touches
   `go.mod`, the checksum, and the `Dockerfile` `golang` digest together.
 
+- 2026-09-21: Collapsed the two duration parsers into one and fixed the
+  `--older-than` months example
+  ([issue #123](https://git.eeqj.de/sneak/vaultik/issues/123)). Two
+  functions named `parseDuration` existed with different grammars;
+  `snapshot purge --older-than` and `--keep-newer-than` both already went
+  through the one in `internal/vaultik`, while the richer copy in
+  `internal/cli/duration.go` was reachable only from its own test. Kept
+  the live-path parser and deleted the unused one, so no flag's accepted
+  grammar changes. The trap the issue was filed over: `README.md`
+  documented `6m` as the months example for `--older-than`, but `m` is
+  minutes, so the documented command deleted every snapshot older than
+  six minutes on a destructive flag. Corrected the doc to `6mo` and put
+  both flags' help text on one example list that states `m` is minutes
+  and `mo` is months. The surviving parser now rejects negatives, which
+  it previously accepted (`-5h`) or silently made positive (`-5d`).
+  Table-driven tests cover every unit, `6m` as six minutes, `6mo` as 180
+  days, and rejection of a bare number, an unknown unit, and a negative.
+
 - 2026-08-10: Moved every lint run into its own container, as a build
   step ([issue #113](https://git.eeqj.de/sneak/vaultik/issues/113)).
   New root `Dockerfile.lint`, built by `script/lint`, runs
@@ -88,10 +135,11 @@ release" is exactly the contradiction
   into each check command, and a fresh `$(date +%s%N)$$` per invocation
   computed as a bare assignment. `cmd/vaultik/lintdocker_test.go`
   parses both Dockerfiles and both scripts and fails if any part of
-  that is dropped, because every way of losing it is silent. Its
-  host-lint assertion is structural — no script runs `golangci-lint`
-  except through `docker` — rather than a search for the one retired
-  variable name, which nothing could ever reintroduce.
+  that is dropped, because every way of losing it is silent. No test
+  asserts that no script runs the host linter: `script/lint` is the one
+  lint entry point and runs `golangci-lint` only inside the container,
+  and keeping it that way is a review matter, not something a test
+  proves.
 
   The product `Dockerfile` lost its lint stage rather than gaining a
   second linter pin: `make lint` is now `docker build`, so the stage

cmd/vaultik/lintdocker_test.go

@@ -28,6 +28,11 @@ import (
 // -- that a real finding actually fails the build -- is verified by
 // hand against a deliberately broken tree, recorded on the pull
 // request.
+//
+// One property is deliberately NOT tested here: that no script runs the
+// linter on the host. script/lint is the only lint entry point, and it
+// runs golangci-lint only inside the container; keeping it that way is a
+// review matter, not something a test in this file establishes.
 
 // The files under guard, relative to the repository root.
 const (
@@ -37,9 +42,8 @@ const (
 	cibuildScript     = "script/cibuild"
 )
 
-// linterBinary is the linter's command name. Every occurrence of it in
-// executable shell in this repo must be inside a docker invocation; see
-// TestNoHostLintPathRemains.
+// linterBinary is the linter's command name, used to locate the
+// config-verify and lint steps in Dockerfile.lint.
 const linterBinary = "golangci-lint"
 
 // checkEpochARG is the declaration, with no default value. A default
@@ -219,90 +223,6 @@ func TestCibuildBuildsBothDockerfilesWithFreshEpochs(t *testing.T) {
 		"%s must build %s", cibuildScript, lintDockerfile)
 }
 
-// TestNoHostLintPathRemains fails if any escape hatch to a host linter
-// comes back. The owner's ruling is that every lint run happens inside
-// a container; a PATH binary that happens to match the pinned version
-// is a different build reached by a different code path, and admitting
-// it is what lets a local pass disagree with CI.
-//
-// This asserts the PROPERTY -- no script invokes the linter except
-// through docker -- rather than the absence of any particular variable
-// name. An earlier version of this test looked only for the literal
-// VAULTIK_LINT_IN_CONTAINER, the name of the hatch that was removed
-// alongside it, so nothing could ever trip it again: a hatch under any
-// other name left it passing. A structural test that passes on a broken
-// tree is worse than no test, because it is what a later reader trusts
-// instead of re-deriving the invariant.
-//
-// script/lint-fix is not exempted. It is the one script that runs the
-// linter as a container rather than as a build step, but it still runs
-// it in one, so the same property holds of it.
-func TestNoHostLintPathRemains(t *testing.T) {
-	t.Parallel()
-
-	root := repoRoot(t)
-
-	entries, err := os.ReadDir(filepath.Join(root, "script"))
-	require.NoError(t, err)
-	require.NotEmpty(t, entries, "no scripts found to scan")
-
-	for _, entry := range entries {
-		if entry.IsDir() {
-			continue
-		}
-
-		name := filepath.Join("script", entry.Name())
-		for _, line := range shellCode(readRepoFile(t, name)) {
-			assertLinterIsContainerised(t, name, line)
-		}
-	}
-}
-
-// assertLinterIsContainerised fails if the line runs the linter without
-// handing it to docker first. Position matters: docker has to come
-// before the binary, or the line is running the host linter and merely
-// mentioning docker afterwards.
-func assertLinterIsContainerised(t *testing.T, name, line string) {
-	t.Helper()
-
-	at := strings.Index(line, linterBinary)
-	if at < 0 {
-		return
-	}
-
-	docker := strings.Index(line, "docker")
-
-	assert.True(t, docker >= 0 && docker < at,
-		"%s runs %s on the host; every lint run happens in a container"+
-			" (line: %s)", name, linterBinary, line)
-}
-
-// TestShellCodeSeesCodeAndNotProse keeps the scanner above honest. It
-// has to ignore comments and here-document bodies, because script/lint
-// and script/bootstrap both NAME golangci-lint in prose -- in comments,
-// and in the error text they print -- precisely to say that the host
-// binary is never used. A scanner that went blind, by over-eager
-// stripping or by failing to join continuation lines, would make
-// TestNoHostLintPathRemains pass on everything.
-func TestShellCodeSeesCodeAndNotProse(t *testing.T) {
-	t.Parallel()
-
-	script := strings.Join([]string{
-		"#!/bin/sh",
-		"# a comment naming golangci-lint",
-		"cat >&2 <<EOF",
-		"prose naming golangci-lint, printed not executed",
-		"EOF",
-		"docker run --rm \\",
-		"    \"$image\" \\",
-		"    golangci-lint run ./...",
-	}, "\n")
-
-	assert.Equal(t,
-		[]string{"cat >&2 <<EOF", `docker run --rm "$image" golangci-lint run ./...`},
-		shellCode(script))
-}
-
 // assertEpochExpandedInto fails unless some instruction runs the named
 // command with the epoch expanded into it. Expansion, not mere
 // declaration: an ARG that no instruction references is not guaranteed
@@ -407,70 +327,6 @@ func indexContaining(found []string, want string) int {
 	return -1
 }
 
-// shellCode returns a POSIX shell script's executable lines: comments
-// dropped, here-document bodies dropped, and backslash continuations
-// joined so a multi-line command is a single string. Whitespace is
-// collapsed, as it is for Dockerfile instructions.
-//
-// Both exclusions are load-bearing rather than tidiness. The scripts
-// name golangci-lint in prose to state that the host binary is never
-// used, and joining continuations is what lets the one legitimate
-// container invocation -- script/lint-fix's `docker run`, whose linter
-// command sits several lines below the word `docker` -- be recognised
-// as containerised.
-func shellCode(contents string) []string {
-	var (
-		out       []string
-		joined    string
-		terminate string
-	)
-
-	for line := range strings.SplitSeq(contents, "\n") {
-		trimmed := strings.TrimSpace(line)
-
-		if terminate != "" {
-			if trimmed == terminate {
-				terminate = ""
-			}
-
-			continue
-		}
-
-		if joined == "" && (trimmed == "" || strings.HasPrefix(trimmed, "#")) {
-			continue
-		}
-
-		joined += strings.TrimSuffix(trimmed, `\`) + " "
-		if strings.HasSuffix(trimmed, `\`) {
-			continue
-		}
-
-		joined = strings.Join(strings.Fields(joined), " ")
-		terminate = heredocTerminator(joined)
-
-		out = append(out, joined)
-		joined = ""
-	}
-
-	return out
-}
-
-// heredocTerminator returns the terminator of the here-document a
-// command opens, or "" if it opens none. Only the first on a line is
-// recognised; nothing in script/ opens two.
-func heredocTerminator(line string) string {
-	_, after, opens := strings.Cut(line, "<<")
-	if !opens {
-		return ""
-	}
-
-	// `<<-` strips leading tabs from the body; the terminator word is
-	// the same either way, and callers compare against trimmed lines.
-	word, _, _ := strings.Cut(strings.TrimPrefix(after, "-"), " ")
-
-	return strings.Trim(word, `'"`)
-}
-
 // readRepoFile reads a file by its path relative to the repository
 // root.
 func readRepoFile(t *testing.T, name string) string {

internal/cli/app.go

@@ -48,6 +48,11 @@ type AppOptions struct {
 // silenced — per the documented convention that --quiet suppresses
 // non-error output only. The startup banner is printed by Entry
 // before cobra parses arguments, gated by the same arg-level check.
+//
+// --json quiets the UI here too, because stdout then carries a JSON
+// document and human narration would corrupt it. Unlike Quiet it does
+// not lower the stderr log level (issue #112), so --verbose/--debug
+// still surface diagnostics alongside the document.
 func setupGlobals(
 	lc fx.Lifecycle, g *globals.Globals, v *vaultik.Vaultik, opts log.Options,
 ) {
@@ -55,7 +60,7 @@ func setupGlobals(
 		OnStart: func(_ context.Context) error {
 			g.StartTime = time.Now().UTC()
 
-			if opts.Cron || opts.Quiet {
+			if opts.Cron || opts.Quiet || opts.JSON {
 				v.UI.SetQuiet(true)
 			}
 
@@ -202,9 +207,10 @@ func RunApp(ctx context.Context, app *fx.App) error {
 // instance in a goroutine, report a failure prefixed with failMsg
 // (suppressed while suppressErrors is true, e.g. under --json), then
 // trigger shutdown. The operation is cancelled when the app stops.
-// extraQuiet is OR-ed into LogOptions.Quiet (e.g. --json output modes).
+// jsonOutput marks a command whose stdout is a JSON document: it quiets
+// the UI but, unlike Quiet, leaves the stderr log level alone.
 func runVaultikApp(
-	cmd *cobra.Command, extraQuiet, suppressErrors bool,
+	cmd *cobra.Command, jsonOutput, suppressErrors bool,
 	failMsg string, op func(v *vaultik.Vaultik) error,
 ) error {
 	configPath, err := ResolveConfigPath()
@@ -219,7 +225,8 @@ func runVaultikApp(
 		LogOptions: log.Options{
 			Verbose: rootFlags.Verbose,
 			Debug:   rootFlags.Debug,
-			Quiet:   rootFlags.Quiet || extraQuiet,
+			Quiet:   rootFlags.Quiet,
+			JSON:    jsonOutput,
 		},
 		Modules: []fx.Option{},
 		Invokes: []fx.Option{

internal/cli/duration.go

@@ -1,126 +0,0 @@
-package cli
-
-import (
-	"errors"
-	"fmt"
-	"regexp"
-	"strconv"
-	"strings"
-	"time"
-)
-
-// Approximate lengths of the extended calendar units accepted by
-// parseDuration.
-const (
-	durationDay   = 24 * time.Hour
-	durationWeek  = 7 * durationDay
-	durationMonth = 30 * durationDay
-	durationYear  = 365 * durationDay
-)
-
-var (
-	errNegativeDuration = errors.New("negative durations are not supported")
-	errInvalidDuration  = errors.New("invalid duration format")
-	errUnknownTimeUnit  = errors.New("unknown time unit")
-)
-
-// parseDuration parses duration strings. Supports standard Go duration format
-// (e.g., "3h30m", "1h45m30s") as well as extended units:
-// - d: days (e.g., "30d", "7d")
-// - w: weeks (e.g., "2w", "4w")
-// - mo: months (30 days) (e.g., "6mo", "1mo")
-// - y: years (365 days) (e.g., "1y", "2y")
-//
-// Can combine units: "1y6mo", "2w3d", "1d12h30m"
-func parseDuration(s string) (time.Duration, error) {
-	// First try standard Go duration parsing
-	d, err := time.ParseDuration(s)
-	if err == nil {
-		return d, nil
-	}
-
-	// Extended duration parsing
-	// Check for negative values
-	if strings.HasPrefix(strings.TrimSpace(s), "-") {
-		return 0, errNegativeDuration
-	}
-
-	// Pattern matches: number + unit, repeated
-	re := regexp.MustCompile(`(\d+(?:\.\d+)?)\s*([a-zA-Z]+)`)
-	matches := re.FindAllStringSubmatch(s, -1)
-
-	if len(matches) == 0 {
-		return 0, fmt.Errorf("%w: %q", errInvalidDuration, s)
-	}
-
-	var total time.Duration
-
-	for _, match := range matches {
-		valueStr := match[1]
-		unit := strings.ToLower(match[2])
-
-		value, err := strconv.ParseFloat(valueStr, 64)
-		if err != nil {
-			return 0, fmt.Errorf("invalid number %q: %w", valueStr, err)
-		}
-
-		d, err := durationForUnit(value, unit)
-		if err != nil {
-			return 0, err
-		}
-
-		total += d
-	}
-
-	return total, nil
-}
-
-// durationForUnit converts a value with a (case-normalized) unit suffix
-// into a time.Duration, accepting Go's standard units plus the extended
-// calendar units.
-func durationForUnit(value float64, unit string) (time.Duration, error) {
-	switch unit {
-	// Standard time units
-	case "ns", "nanosecond", "nanoseconds":
-		return time.Duration(value), nil
-	case "us", "µs", "microsecond", "microseconds":
-		return time.Duration(value * float64(time.Microsecond)), nil
-	case "ms", "millisecond", "milliseconds":
-		return time.Duration(value * float64(time.Millisecond)), nil
-	case "s", "sec", "second", "seconds":
-		return time.Duration(value * float64(time.Second)), nil
-	case "m", "min", "minute", "minutes":
-		return time.Duration(value * float64(time.Minute)), nil
-	case "h", "hr", "hour", "hours":
-		return time.Duration(value * float64(time.Hour)), nil
-	// Extended units
-	case "d", "day", "days":
-		return time.Duration(value * float64(durationDay)), nil
-	case "w", "week", "weeks":
-		return time.Duration(value * float64(durationWeek)), nil
-	case "mo", "month", "months":
-		// Using 30 days as approximation
-		return time.Duration(value * float64(durationMonth)), nil
-	case "y", "year", "years":
-		// Using 365 days as approximation
-		return time.Duration(value * float64(durationYear)), nil
-	default:
-		// Try parsing as standard Go duration unit
-		testStr := "1" + unit
-
-		_, err := time.ParseDuration(testStr)
-		if err != nil {
-			return 0, fmt.Errorf("%w: %q", errUnknownTimeUnit, unit)
-		}
-
-		// It's a valid Go duration unit, parse the full value
-		fullStr := fmt.Sprintf("%g%s", value, unit)
-
-		d, err := time.ParseDuration(fullStr)
-		if err != nil {
-			return 0, fmt.Errorf("invalid duration %q: %w", fullStr, err)
-		}
-
-		return d, nil
-	}
-}

internal/cli/duration_test.go

@@ -1,299 +0,0 @@
-package cli //nolint:testpackage // needs access to unexported parseDuration
-
-import (
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-type parseDurationCase struct {
-	name     string
-	input    string
-	expected time.Duration
-	wantErr  bool
-}
-
-// runParseDurationCases executes a table of parseDuration cases as
-// parallel subtests.
-func runParseDurationCases(t *testing.T, tests []parseDurationCase) {
-	t.Helper()
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			t.Parallel()
-
-			got, err := parseDuration(tt.input)
-
-			if tt.wantErr {
-				require.Error(t, err, "expected error for input %q", tt.input)
-
-				return
-			}
-
-			require.NoError(t, err, "unexpected error for input %q", tt.input)
-			assert.Equal(t, tt.expected, got, "duration mismatch for input %q", tt.input)
-		})
-	}
-}
-
-func TestParseDurationStandard(t *testing.T) {
-	t.Parallel()
-
-	runParseDurationCases(t, []parseDurationCase{
-		{
-			name:     "standard seconds",
-			input:    "30s",
-			expected: 30 * time.Second,
-		},
-		{
-			name:     "standard minutes",
-			input:    "45m",
-			expected: 45 * time.Minute,
-		},
-		{
-			name:     "standard hours",
-			input:    "2h",
-			expected: 2 * time.Hour,
-		},
-		{
-			name:     "standard combined",
-			input:    "3h30m",
-			expected: 3*time.Hour + 30*time.Minute,
-		},
-		{
-			name:     "standard complex",
-			input:    "1h45m30s",
-			expected: 1*time.Hour + 45*time.Minute + 30*time.Second,
-		},
-		{
-			name:     "standard with milliseconds",
-			input:    "1s500ms",
-			expected: 1*time.Second + 500*time.Millisecond,
-		},
-	})
-}
-
-func TestParseDurationExtendedUnits(t *testing.T) {
-	t.Parallel()
-
-	runParseDurationCases(t, []parseDurationCase{
-		// Extended units - days
-		{
-			name:     "single day",
-			input:    "1d",
-			expected: 24 * time.Hour,
-		},
-		{
-			name:     "multiple days",
-			input:    "7d",
-			expected: 7 * 24 * time.Hour,
-		},
-		{
-			name:     "fractional days",
-			input:    "1.5d",
-			expected: 36 * time.Hour,
-		},
-		{
-			name:     "days spelled out",
-			input:    "3days",
-			expected: 3 * 24 * time.Hour,
-		},
-		// Extended units - weeks
-		{
-			name:     "single week",
-			input:    "1w",
-			expected: 7 * 24 * time.Hour,
-		},
-		{
-			name:     "multiple weeks",
-			input:    "4w",
-			expected: 4 * 7 * 24 * time.Hour,
-		},
-		{
-			name:     "weeks spelled out",
-			input:    "2weeks",
-			expected: 2 * 7 * 24 * time.Hour,
-		},
-		// Extended units - months
-		{
-			name:     "single month",
-			input:    "1mo",
-			expected: 30 * 24 * time.Hour,
-		},
-		{
-			name:     "multiple months",
-			input:    "6mo",
-			expected: 6 * 30 * 24 * time.Hour,
-		},
-		{
-			name:     "months spelled out",
-			input:    "3months",
-			expected: 3 * 30 * 24 * time.Hour,
-		},
-		// Extended units - years
-		{
-			name:     "single year",
-			input:    "1y",
-			expected: 365 * 24 * time.Hour,
-		},
-		{
-			name:     "multiple years",
-			input:    "2y",
-			expected: 2 * 365 * 24 * time.Hour,
-		},
-		{
-			name:     "years spelled out",
-			input:    "1year",
-			expected: 365 * 24 * time.Hour,
-		},
-	})
-}
-
-func TestParseDurationCombinedAndErrors(t *testing.T) {
-	t.Parallel()
-
-	runParseDurationCases(t, []parseDurationCase{
-		// Combined extended units
-		{
-			name:     "weeks and days",
-			input:    "2w3d",
-			expected: 2*7*24*time.Hour + 3*24*time.Hour,
-		},
-		{
-			name:     "years and months",
-			input:    "1y6mo",
-			expected: 365*24*time.Hour + 6*30*24*time.Hour,
-		},
-		{
-			name:     "days and hours",
-			input:    "1d12h",
-			expected: 24*time.Hour + 12*time.Hour,
-		},
-		{
-			name:  "complex combination",
-			input: "1y2mo3w4d5h6m7s",
-			expected: 365*24*time.Hour + 2*30*24*time.Hour +
-				3*7*24*time.Hour + 4*24*time.Hour +
-				5*time.Hour + 6*time.Minute + 7*time.Second,
-		},
-		{
-			name:     "with spaces",
-			input:    "1d 12h 30m",
-			expected: 24*time.Hour + 12*time.Hour + 30*time.Minute,
-		},
-		// Edge cases
-		{
-			name:     "zero duration",
-			input:    "0s",
-			expected: 0,
-		},
-		{
-			name:     "large duration",
-			input:    "10y",
-			expected: 10 * 365 * 24 * time.Hour,
-		},
-		// Error cases
-		{
-			name:    "empty string",
-			input:   "",
-			wantErr: true,
-		},
-		{
-			name:    "invalid format",
-			input:   "abc",
-			wantErr: true,
-		},
-		{
-			name:    "unknown unit",
-			input:   "5x",
-			wantErr: true,
-		},
-		{
-			name:    "invalid number",
-			input:   "xyzd",
-			wantErr: true,
-		},
-		{
-			name:    "negative not supported",
-			input:   "-5d",
-			wantErr: true,
-		},
-	})
-}
-
-func TestParseDurationSpecialCases(t *testing.T) {
-	t.Parallel()
-
-	// Test that standard Go durations work exactly as expected
-	standardDurations := []string{
-		"300ms",
-		"1.5h",
-		"2h45m",
-		"72h",
-		"1us",
-		"1µs",
-		"1ns",
-	}
-
-	for _, d := range standardDurations {
-		expected, err := time.ParseDuration(d)
-		require.NoError(t, err)
-
-		got, err := parseDuration(d)
-		require.NoError(t, err)
-		assert.Equal(t, expected, got, "standard duration %q should parse identically", d)
-	}
-}
-
-func TestParseDurationRealWorldExamples(t *testing.T) {
-	t.Parallel()
-
-	// Test real-world snapshot purge scenarios
-	tests := []struct {
-		description string
-		input       string
-		olderThan   time.Duration
-	}{
-		{
-			description: "keep snapshots from last 30 days",
-			input:       "30d",
-			olderThan:   30 * 24 * time.Hour,
-		},
-		{
-			description: "keep snapshots from last 6 months",
-			input:       "6mo",
-			olderThan:   6 * 30 * 24 * time.Hour,
-		},
-		{
-			description: "keep snapshots from last year",
-			input:       "1y",
-			olderThan:   365 * 24 * time.Hour,
-		},
-		{
-			description: "keep snapshots from last week and a half",
-			input:       "1w3d",
-			olderThan:   10 * 24 * time.Hour,
-		},
-		{
-			description: "keep snapshots from last 90 days",
-			input:       "90d",
-			olderThan:   90 * 24 * time.Hour,
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.description, func(t *testing.T) {
-			t.Parallel()
-
-			got, err := parseDuration(tt.input)
-			require.NoError(t, err)
-			assert.Equal(t, tt.olderThan, got)
-
-			// Verify the duration makes sense for snapshot purging
-			assert.Greater(t, got, time.Hour,
-				"snapshot purge duration should be at least an hour")
-		})
-	}
-}

internal/cli/entry_prune_json_stderr_test.go

@@ -0,0 +1,139 @@
+package cli //nolint:testpackage // shares the prune fixtures and capture helpers
+
+import (
+	"bytes"
+	"io"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// staleRecordLogMessage is the local-cleanup audit line CleanupLocalSnapshots
+// logs for each stale record. It is exactly the signal issue #112 says a
+// machine consumer lost under --json: gated off stdout, and pinned below
+// the log level on stderr because --json used to force Quiet.
+const staleRecordLogMessage = "Removing stale local snapshot record"
+
+// TestEntryPruneJSONStderrHonoursVerbosity is the end-to-end regression
+// guard for issue #112. Under --json the log level must still follow
+// --verbose/--debug rather than being pinned to WARN, so the
+// local-cleanup records reach stderr under --verbose while stdout stays
+// exactly one JSON document; without --verbose they stay below the
+// level, as they do without --json.
+//
+// Both halves are asserted together on the same run, because the fix has
+// to keep the document clean (issue #108) while freeing stderr.
+//
+// Not parallel: it replaces os.Args, os.Stdout, os.Stderr and the xdg
+// globals.
+//
+//nolint:paralleltest // replaces os.Args, os.Stdout, os.Stderr and the xdg globals
+func TestEntryPruneJSONStderrHonoursVerbosity(t *testing.T) {
+	for _, testCase := range []struct {
+		name         string
+		verbose      bool
+		wantOnStderr bool
+	}{
+		{
+			name:         "verbose json surfaces the cleanup record on stderr",
+			verbose:      true,
+			wantOnStderr: true,
+		},
+		{
+			name:         "json alone keeps the cleanup record below the level",
+			verbose:      false,
+			wantOnStderr: false,
+		},
+	} {
+		t.Run(testCase.name, func(t *testing.T) {
+			configPath := writeHermeticPruneConfig(t, true)
+
+			previousArgs := os.Args
+
+			t.Cleanup(func() {
+				os.Args = previousArgs
+				rootFlags = RootFlags{}
+			})
+
+			args := []string{
+				programName, flagConfig, configPath, cmdPrune, flagJSON,
+			}
+			if testCase.verbose {
+				args = append(args, "--verbose")
+			}
+
+			os.Args = args
+
+			stdout, stderr := captureProcessStdoutAndStderr(t, Entry)
+
+			// The document stays clean in both cases: freeing stderr must
+			// not regress issue #108.
+			requireExactlyOneJSONDocument(t, stdout)
+
+			if testCase.wantOnStderr {
+				assert.Contains(t, stderr, staleRecordLogMessage,
+					"--verbose --json must emit the cleanup record on stderr")
+				assert.Contains(t, stderr, stalePruneSnapshotID,
+					"the record must name the snapshot it removed")
+			} else {
+				assert.NotContains(t, stderr, staleRecordLogMessage,
+					"without --verbose the record stays below the log level")
+			}
+		})
+	}
+}
+
+// captureProcessStdoutAndStderr redirects both of the process's own
+// standard streams to pipes for the duration of fn and returns what was
+// written to each. The redirection is at the file-descriptor level
+// because the logger binds os.Stderr when it initializes inside fn, and
+// the JSON document reaches os.Stdout independently; the point is to see
+// where each actually lands.
+//
+// Not parallel-safe: os.Stdout and os.Stderr are process-global.
+func captureProcessStdoutAndStderr(t *testing.T, fn func()) (string, string) {
+	t.Helper()
+
+	outReader, outWriter, err := os.Pipe()
+	require.NoError(t, err)
+
+	errReader, errWriter, err := os.Pipe()
+	require.NoError(t, err)
+
+	previousOut, previousErr := os.Stdout, os.Stderr
+	os.Stdout, os.Stderr = outWriter, errWriter
+
+	capturedOut := drain(outReader)
+	capturedErr := drain(errReader)
+
+	fn()
+
+	os.Stdout, os.Stderr = previousOut, previousErr
+
+	require.NoError(t, outWriter.Close())
+	require.NoError(t, errWriter.Close())
+
+	out, errOut := <-capturedOut, <-capturedErr
+
+	require.NoError(t, outReader.Close())
+	require.NoError(t, errReader.Close())
+
+	return out, errOut
+}
+
+// drain copies a reader to a string on a goroutine and delivers the
+// result once the writer end is closed.
+func drain(reader io.Reader) <-chan string {
+	captured := make(chan string, 1)
+
+	go func() {
+		var buf bytes.Buffer
+
+		_, _ = io.Copy(&buf, reader)
+		captured <- buf.String()
+	}()
+
+	return captured
+}

internal/cli/prune.go

@@ -46,7 +46,8 @@ work (e.g. after a crashed backup or to reclaim storage).`,
 				LogOptions: log.Options{
 					Verbose: rootFlags.Verbose,
 					Debug:   rootFlags.Debug,
-					Quiet:   rootFlags.Quiet || opts.JSON,
+					Quiet:   rootFlags.Quiet,
+					JSON:    opts.JSON,
 				},
 				Modules: []fx.Option{},
 				Invokes: []fx.Option{

internal/cli/remote.go

@@ -88,7 +88,8 @@ func newRemoteInfoCommand() *cobra.Command {
 				LogOptions: log.Options{
 					Verbose: rootFlags.Verbose,
 					Debug:   rootFlags.Debug,
-					Quiet:   rootFlags.Quiet || jsonOutput,
+					Quiet:   rootFlags.Quiet,
+					JSON:    jsonOutput,
 				},
 				Modules: []fx.Option{},
 				Invokes: []fx.Option{

internal/cli/snapshot.go

@@ -141,7 +141,8 @@ specifying a path using --config or by setting VAULTIK_CONFIG to a path.`,
 			"orphaned blobs")
 	cmd.Flags().StringVar(&opts.KeepNewerThan, "keep-newer-than", "",
 		"With --prune: keep snapshots newer than this duration "+
-			"(e.g. 4w, 30d, 6mo) instead of only the latest")
+			"(e.g. 30d, 4w, 6mo, 1y; m is minutes, mo is months) "+
+			"instead of only the latest")
 
 	return cmd
 }
@@ -204,7 +205,8 @@ restrict the operation to specific snapshot names.`,
 	cmd.Flags().BoolVar(&opts.KeepLatest, "keep-latest", false,
 		"Keep only the latest snapshot of each name")
 	cmd.Flags().StringVar(&opts.OlderThan, "older-than", "",
-		"Remove snapshots older than duration (e.g., 30d, 6m, 1y)")
+		"Remove snapshots older than duration "+
+			"(e.g. 30d, 4w, 6mo, 1y; m is minutes, mo is months)")
 	cmd.Flags().BoolVar(&opts.Force, "force", false, "Skip confirmation prompt")
 	cmd.Flags().StringArrayVar(&opts.Names, "snapshot", nil,
 		"Restrict to snapshots with these names (repeat for multiple)")
@@ -237,7 +239,8 @@ func newSnapshotVerifyCommand() *cobra.Command {
 				LogOptions: log.Options{
 					Verbose: rootFlags.Verbose,
 					Debug:   rootFlags.Debug,
-					Quiet:   rootFlags.Quiet || opts.JSON,
+					Quiet:   rootFlags.Quiet,
+					JSON:    opts.JSON,
 				},
 				Modules: []fx.Option{},
 				Invokes: []fx.Option{

internal/log/module.go

@@ -14,8 +14,18 @@ var Module = fx.Module("log",
 )
 
 // New creates a new logger configuration from provided options.
+//
+// JSON is intentionally not carried into Config: a command emitting a
+// JSON document on stdout must keep its stderr log level under
+// --verbose/--debug, so --json must not lower it (issue #112). JSON
+// silences the stdout UI in setupGlobals instead.
 func New(opts Options) Config {
-	return Config(opts)
+	return Config{
+		Verbose: opts.Verbose,
+		Debug:   opts.Debug,
+		Cron:    opts.Cron,
+		Quiet:   opts.Quiet,
+	}
 }
 
 // Options are provided by the CLI.
@@ -24,4 +34,8 @@ type Options struct {
 	Debug   bool
 	Cron    bool
 	Quiet   bool
+	// JSON marks a command whose stdout carries a machine-readable
+	// document. It silences the human UI on stdout (see setupGlobals),
+	// but unlike Quiet it leaves the stderr log level alone.
+	JSON bool
 }

internal/s3/client.go

@@ -219,11 +219,7 @@ func (c *Client) HeadObject(ctx context.Context, key string) (bool, error) {
 		Key:    aws.String(fullKey),
 	})
 	if err != nil {
-		var (
-			notFound  *s3types.NotFound
-			noSuchKey *s3types.NoSuchKey
-		)
-		if errors.As(err, &notFound) || errors.As(err, &noSuchKey) {
+		if IsNotFound(err) {
 			return false, nil
 		}
 
@@ -233,6 +229,18 @@ func (c *Client) HeadObject(ctx context.Context, key string) (bool, error) {
 	return true, nil
 }
 
+// IsNotFound reports whether err indicates that an object does not exist.
+// Head and Get requests surface a missing object as different SDK types,
+// so both are checked here.
+func IsNotFound(err error) bool {
+	var (
+		notFound  *s3types.NotFound
+		noSuchKey *s3types.NoSuchKey
+	)
+
+	return errors.As(err, &notFound) || errors.As(err, &noSuchKey)
+}
+
 // ObjectInfo contains information about an S3 object.
 // It is used by ListObjectsStream to return object metadata
 // along with any errors encountered during listing.

internal/storage/file.go

@@ -46,31 +46,18 @@ func (f *FileStorer) SetFilesystem(fs afero.Fs) {
 // storage base path.
 const storageDirPerm = 0o755
 
+// tempSuffix marks a partially written object. writeAtomic streams into a
+// temp file carrying this suffix and only renames it onto the real key once
+// the whole object is on disk, so an interrupted write can never leave a
+// truncated object at the key a later run would Stat and trust as a complete
+// blob. List and ListStream skip these files, so a leftover from an
+// interrupted write is never listed or trusted as a blob; it is otherwise
+// harmless and is overwritten when the same key is written again.
+const tempSuffix = ".partial"
+
 // Put stores data at the specified key.
 func (f *FileStorer) Put(_ context.Context, key string, data io.Reader) error {
-	path := f.fullPath(key)
-
-	// Create parent directories
-	dir := filepath.Dir(path)
-
-	err := f.fs.MkdirAll(dir, storageDirPerm)
-	if err != nil {
-		return fmt.Errorf("creating directories: %w", err)
-	}
-
-	file, err := f.fs.Create(path)
-	if err != nil {
-		return fmt.Errorf("creating file: %w", err)
-	}
-
-	defer func() { _ = file.Close() }()
-
-	_, err = io.Copy(file, data)
-	if err != nil {
-		return fmt.Errorf("writing file: %w", err)
-	}
-
-	return nil
+	return f.writeAtomic(key, data, nil)
 }
 
 // PutWithProgress stores data with progress reporting.
@@ -78,35 +65,7 @@ func (f *FileStorer) PutWithProgress(
 	_ context.Context, key string, data io.Reader,
 	_ int64, progress ProgressCallback,
 ) error {
-	path := f.fullPath(key)
-
-	// Create parent directories
-	dir := filepath.Dir(path)
-
-	err := f.fs.MkdirAll(dir, storageDirPerm)
-	if err != nil {
-		return fmt.Errorf("creating directories: %w", err)
-	}
-
-	file, err := f.fs.Create(path)
-	if err != nil {
-		return fmt.Errorf("creating file: %w", err)
-	}
-
-	defer func() { _ = file.Close() }()
-
-	// Wrap with progress tracking
-	pw := &progressWriter{
-		writer:   file,
-		callback: progress,
-	}
-
-	_, err = io.Copy(pw, data)
-	if err != nil {
-		return fmt.Errorf("writing file: %w", err)
-	}
-
-	return nil
+	return f.writeAtomic(key, data, progress)
 }
 
 // Get retrieves data from the specified key.
@@ -188,7 +147,7 @@ func (f *FileStorer) List(ctx context.Context, prefix string) ([]string, error)
 		default:
 		}
 
-		if !info.IsDir() {
+		if !info.IsDir() && !strings.HasSuffix(info.Name(), tempSuffix) {
 			// Convert back to key (relative path from basePath)
 			relPath, err := filepath.Rel(f.basePath, path)
 			if err != nil {
@@ -245,7 +204,7 @@ func (f *FileStorer) ListStream(ctx context.Context, prefix string) <-chan Objec
 				return nil //nolint:nilerr // continue walking despite errors
 			}
 
-			if !info.IsDir() {
+			if !info.IsDir() && !strings.HasSuffix(info.Name(), tempSuffix) {
 				relPath, err := filepath.Rel(f.basePath, path)
 				if err != nil {
 					ch <- ObjectInfo{Err: fmt.Errorf("computing relative path: %w", err)}
@@ -275,6 +234,72 @@ func (f *FileStorer) Info() Info {
 	}
 }
 
+// writeAtomic streams data into a temp file in the destination directory,
+// fsyncs it, and renames it onto the final key. The key therefore appears
+// only once the whole object has been durably written; a failure part-way
+// leaves a temp file (removed here on the failing path) rather than a
+// truncated object at the key.
+func (f *FileStorer) writeAtomic(
+	key string, data io.Reader, progress ProgressCallback,
+) error {
+	path := f.fullPath(key)
+	dir := filepath.Dir(path)
+
+	err := f.fs.MkdirAll(dir, storageDirPerm)
+	if err != nil {
+		return fmt.Errorf("creating directories: %w", err)
+	}
+
+	tmp, err := afero.TempFile(f.fs, dir, filepath.Base(path)+"-*"+tempSuffix)
+	if err != nil {
+		return fmt.Errorf("creating temp file: %w", err)
+	}
+
+	tmpPath := tmp.Name()
+
+	// Remove the temp file unless the rename below claims it. On the success
+	// path renamed is true, so the deferred Close and Remove are harmless
+	// no-ops on a name that no longer exists.
+	renamed := false
+
+	defer func() {
+		_ = tmp.Close()
+
+		if !renamed {
+			_ = f.fs.Remove(tmpPath)
+		}
+	}()
+
+	var w io.Writer = tmp
+	if progress != nil {
+		w = &progressWriter{writer: tmp, callback: progress}
+	}
+
+	_, err = io.Copy(w, data)
+	if err != nil {
+		return fmt.Errorf("writing file: %w", err)
+	}
+
+	err = tmp.Sync()
+	if err != nil {
+		return fmt.Errorf("syncing temp file: %w", err)
+	}
+
+	err = tmp.Close()
+	if err != nil {
+		return fmt.Errorf("closing temp file: %w", err)
+	}
+
+	err = f.fs.Rename(tmpPath, path)
+	if err != nil {
+		return fmt.Errorf("renaming temp file: %w", err)
+	}
+
+	renamed = true
+
+	return nil
+}
+
 // fullPath returns the full filesystem path for a key.
 func (f *FileStorer) fullPath(key string) string {
 	return filepath.Join(f.basePath, key)

internal/storage/file_atomic_test.go

@@ -0,0 +1,119 @@
+package storage_test
+
+import (
+	"context"
+	"errors"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"sneak.berlin/go/vaultik/internal/storage"
+)
+
+// errStreamInterrupted stands in for an upload cut off mid-stream.
+var errStreamInterrupted = errors.New("connection reset mid-upload")
+
+// failingReader yields its data once, then fails.
+type failingReader struct {
+	data []byte
+	done bool
+}
+
+func (r *failingReader) Read(p []byte) (int, error) {
+	if r.done {
+		return 0, errStreamInterrupted
+	}
+
+	n := copy(p, r.data)
+	r.done = true
+
+	return n, nil
+}
+
+// TestFileStorer_InterruptedWriteLeavesNoTrustedObject checks that a write
+// cut off mid-stream leaves nothing at the destination key, so a later run
+// cannot Stat a truncated object and trust it as a complete blob.
+func TestFileStorer_InterruptedWriteLeavesNoTrustedObject(t *testing.T) {
+	t.Parallel()
+
+	f, err := storage.NewFileStorer(t.TempDir())
+	if err != nil {
+		t.Fatalf("NewFileStorer: %v", err)
+	}
+
+	ctx := context.Background()
+	key := "blobs/aa/bb/aabbccddeeff"
+
+	err = f.PutWithProgress(ctx, key, &failingReader{data: []byte("partial")}, 4096, nil)
+	if err == nil {
+		t.Fatal("expected the interrupted write to fail, got nil")
+	}
+
+	_, err = f.Stat(ctx, key)
+	if !errors.Is(err, storage.ErrNotFound) {
+		t.Fatalf("expected key absent after interrupted write, got Stat err %v", err)
+	}
+
+	keys, err := f.List(ctx, "blobs/")
+	if err != nil {
+		t.Fatalf("List: %v", err)
+	}
+
+	if len(keys) != 0 {
+		t.Fatalf("expected no keys listed after interrupted write, got %v", keys)
+	}
+}
+
+// TestFileStorer_ListSkipsPartialFiles checks that a leftover temp file (the
+// storage layer names them with a ".partial" suffix) is never surfaced as a
+// key by List or ListStream.
+func TestFileStorer_ListSkipsPartialFiles(t *testing.T) {
+	t.Parallel()
+
+	base := t.TempDir()
+
+	f, err := storage.NewFileStorer(base)
+	if err != nil {
+		t.Fatalf("NewFileStorer: %v", err)
+	}
+
+	ctx := context.Background()
+	realKey := "blobs/aa/bb/aabbccddeeff"
+
+	err = f.Put(ctx, realKey, strings.NewReader("blob-bytes"))
+	if err != nil {
+		t.Fatalf("Put: %v", err)
+	}
+
+	// A stray temp file, as an interrupted write would leave behind.
+	leftover := filepath.Join(base, "blobs/aa/bb/aabbccddeeff-123456.partial")
+
+	err = os.WriteFile(leftover, []byte("half"), 0o600)
+	if err != nil {
+		t.Fatalf("writing leftover temp file: %v", err)
+	}
+
+	keys, err := f.List(ctx, "blobs/")
+	if err != nil {
+		t.Fatalf("List: %v", err)
+	}
+
+	if len(keys) != 1 || keys[0] != realKey {
+		t.Fatalf("List should return only the real key, got %v", keys)
+	}
+
+	var streamed []string
+
+	for obj := range f.ListStream(ctx, "blobs/") {
+		if obj.Err != nil {
+			t.Fatalf("ListStream: %v", obj.Err)
+		}
+
+		streamed = append(streamed, obj.Key)
+	}
+
+	if len(streamed) != 1 || streamed[0] != realKey {
+		t.Fatalf("ListStream should return only the real key, got %v", streamed)
+	}
+}

internal/storage/s3.go

@@ -38,14 +38,29 @@ func (s *S3Storer) PutWithProgress(
 }
 
 // Get retrieves data from the specified key.
+// Returns ErrNotFound if the object does not exist.
 func (s *S3Storer) Get(ctx context.Context, key string) (io.ReadCloser, error) {
-	return s.client.GetObject(ctx, key)
+	rc, err := s.client.GetObject(ctx, key)
+	if err != nil {
+		if s3.IsNotFound(err) {
+			return nil, fmt.Errorf("get %q: %w", key, ErrNotFound)
+		}
+
+		return nil, err
+	}
+
+	return rc, nil
 }
 
 // Stat returns metadata about an object without retrieving its contents.
+// Returns ErrNotFound if the object does not exist.
 func (s *S3Storer) Stat(ctx context.Context, key string) (*ObjectInfo, error) {
 	info, err := s.client.StatObject(ctx, key)
 	if err != nil {
+		if s3.IsNotFound(err) {
+			return nil, fmt.Errorf("stat %q: %w", key, ErrNotFound)
+		}
+
 		return nil, err
 	}
 

internal/storage/s3_test.go

@@ -0,0 +1,59 @@
+package storage_test
+
+import (
+	"context"
+	"errors"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/johannesboyne/gofakes3"
+	"github.com/johannesboyne/gofakes3/backend/s3mem"
+
+	"sneak.berlin/go/vaultik/internal/s3"
+	"sneak.berlin/go/vaultik/internal/storage"
+)
+
+// TestS3StorerMissingKeyMapsToErrNotFound verifies that the s3 backend reports
+// a missing object as storage.ErrNotFound, matching the file and rclone
+// backends and the Storer contract. Without the mapping, Get and Stat leak the
+// raw SDK error and errors.Is(err, storage.ErrNotFound) is false.
+//
+//nolint:paralleltest // shares an in-process S3 server via t.Cleanup
+func TestS3StorerMissingKeyMapsToErrNotFound(t *testing.T) {
+	const bucket = "test-bucket"
+
+	backend := s3mem.New()
+
+	err := backend.CreateBucket(bucket)
+	if err != nil {
+		t.Fatalf("create bucket: %v", err)
+	}
+
+	srv := httptest.NewServer(gofakes3.New(backend).Server())
+	t.Cleanup(srv.Close)
+
+	ctx := context.Background()
+
+	client, err := s3.NewClient(ctx, s3.Config{
+		Endpoint:        srv.URL,
+		Bucket:          bucket,
+		AccessKeyID:     "test",
+		SecretAccessKey: "test",
+		Region:          "us-east-1",
+	})
+	if err != nil {
+		t.Fatalf("new client: %v", err)
+	}
+
+	storer := storage.NewS3Storer(client)
+
+	_, err = storer.Get(ctx, "does-not-exist")
+	if !errors.Is(err, storage.ErrNotFound) {
+		t.Errorf("Get on missing key: got %v, want ErrNotFound", err)
+	}
+
+	_, err = storer.Stat(ctx, "does-not-exist")
+	if !errors.Is(err, storage.ErrNotFound) {
+		t.Errorf("Stat on missing key: got %v, want ErrNotFound", err)
+	}
+}

internal/vaultik/deep_verify_test.go

@@ -0,0 +1,108 @@
+package vaultik_test
+
+import (
+	"context"
+	"io"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/spf13/afero"
+	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/vaultik/internal/log"
+	"sneak.berlin/go/vaultik/internal/ui"
+	"sneak.berlin/go/vaultik/internal/vaultik"
+)
+
+// TestDeepVerifyAcceptsHealthyAndRejectsCorruptBlob backs up a real
+// snapshot with the on-disk storage backend, runs deep verification on
+// it, then flips a byte inside one stored blob and runs deep
+// verification again. A healthy snapshot must pass; a corrupted blob
+// must fail. The healthy case is the regression guard: deep
+// verification used to hash the encrypted blob bytes and compare them
+// to the blob's ID (the double SHA256 of the plaintext), so it reported
+// every healthy blob as corrupt.
+func TestDeepVerifyAcceptsHealthyAndRejectsCorruptBlob(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	fs := afero.NewOsFs()
+	tempDir := t.TempDir()
+
+	dataDir := filepath.Join(tempDir, "source")
+	storeDir := filepath.Join(tempDir, "remote")
+	dbPath := filepath.Join(tempDir, "index.sqlite")
+
+	chunkSize := int64(64 * 1024)
+	maxBlobSize := int64(512 * 1024)
+
+	// One file large enough to span several chunks within a single blob.
+	require.NoError(t, fs.MkdirAll(dataDir, 0o755))
+	require.NoError(t, afero.WriteFile(fs,
+		filepath.Join(dataDir, "data.bin"),
+		bytesPattern("deep-", int(chunkSize*3)), 0o644))
+
+	ctx := context.Background()
+
+	// runFileStorageBackup writes a real snapshot to storeDir and closes
+	// the source index, so verification runs from remote bytes only.
+	cfg, storer, snapshotID := runFileStorageBackup(
+		ctx, t, fs, dataDir, storeDir, dbPath, chunkSize, maxBlobSize)
+
+	newVerifier := func() *vaultik.Vaultik {
+		v := &vaultik.Vaultik{
+			Config:  cfg,
+			Storage: storer,
+			Fs:      fs,
+			Stdout:  io.Discard,
+			Stderr:  io.Discard,
+			UI:      ui.NewWithColor(io.Discard, false),
+		}
+		v.SetContext(ctx)
+
+		return v
+	}
+
+	require.NoError(t,
+		newVerifier().RunDeepVerify(snapshotID, &vaultik.VerifyOptions{Deep: true}),
+		"deep verify should pass on a healthy snapshot")
+
+	// Flip a byte inside one blob without changing its length, so the
+	// blob-existence and size checks still pass and verification reaches
+	// the blob-content stage.
+	corruptOneBlob(t, fs, filepath.Join(storeDir, "blobs"))
+
+	require.Error(t,
+		newVerifier().RunDeepVerify(snapshotID, &vaultik.VerifyOptions{Deep: true}),
+		"deep verify should fail on a corrupted blob")
+}
+
+// corruptOneBlob flips a middle byte of the first blob file found under
+// blobsDir, leaving the file length unchanged.
+func corruptOneBlob(t *testing.T, fs afero.Fs, blobsDir string) {
+	t.Helper()
+
+	var blobPath string
+
+	err := afero.Walk(fs, blobsDir,
+		func(path string, info os.FileInfo, err error) error {
+			if err != nil {
+				return err
+			}
+
+			if blobPath == "" && !info.IsDir() {
+				blobPath = path
+			}
+
+			return nil
+		})
+	require.NoError(t, err)
+	require.NotEmpty(t, blobPath, "expected at least one blob on disk")
+
+	data, err := afero.ReadFile(fs, blobPath)
+	require.NoError(t, err)
+	require.NotEmpty(t, data)
+
+	data[len(data)/2] ^= 0xff
+	require.NoError(t, afero.WriteFile(fs, blobPath, data, 0o644))
+}

internal/vaultik/helpers.go

@@ -35,6 +35,7 @@ var (
 		"invalid snapshot ID format: expected hostname_snapshotname_timestamp")
 	errInvalidDuration  = errors.New("invalid duration")
 	errUnknownTimeUnit  = errors.New("unknown time unit")
+	errNegativeDuration = errors.New("negative durations are not supported")
 )
 
 // Time-unit lengths used by parseDuration.
@@ -138,8 +139,13 @@ func parseSnapshotName(snapshotID string) string {
 
 // parseDuration parses a duration string with support for human-friendly units:
 // d/day/days, w/week/weeks, mo/month/months, y/year/years, plus standard Go
-// duration units (h, m, s).
+// duration units. Following Go, m is minutes and mo is months. A bare number,
+// an unknown unit, and a negative value are all rejected.
 func parseDuration(s string) (time.Duration, error) {
+	if strings.HasPrefix(strings.TrimSpace(s), "-") {
+		return 0, errNegativeDuration
+	}
+
 	d, err := time.ParseDuration(s)
 	if err == nil {
 		return d, nil

internal/vaultik/helpers_test.go

@@ -51,13 +51,32 @@ func TestParseDuration(t *testing.T) {
 		want  time.Duration
 		err   bool
 	}{
-		{"30d", 30 * 24 * time.Hour, false},
-		{"4w", 4 * 7 * 24 * time.Hour, false},
-		{"6mo", 6 * 30 * 24 * time.Hour, false},
-		{"1y", 365 * 24 * time.Hour, false},
-		{"2w3d", 2*7*24*time.Hour + 3*24*time.Hour, false},
-		{"1h", time.Hour, false},
+		// Go units, including the m-is-minutes / mo-is-months distinction
+		// that this parser exists to keep straight.
+		{"10ns", 10 * time.Nanosecond, false},
+		{"10us", 10 * time.Microsecond, false},
+		{"500ms", 500 * time.Millisecond, false},
 		{"30s", 30 * time.Second, false},
+		{"6m", 6 * time.Minute, false},
+		{"1h", time.Hour, false},
+		// Extended calendar units.
+		{"30d", 30 * 24 * time.Hour, false},
+		{"3days", 3 * 24 * time.Hour, false},
+		{"4w", 4 * 7 * 24 * time.Hour, false},
+		{"2weeks", 2 * 7 * 24 * time.Hour, false},
+		{"6mo", 180 * 24 * time.Hour, false},
+		{"1month", 30 * 24 * time.Hour, false},
+		{"1y", 365 * 24 * time.Hour, false},
+		{"2years", 2 * 365 * 24 * time.Hour, false},
+		// Combined units.
+		{"2w3d", 2*7*24*time.Hour + 3*24*time.Hour, false},
+		{"1y6mo", 365*24*time.Hour + 180*24*time.Hour, false},
+		// Rejected inputs.
+		{"6", 0, true},   // bare number, no unit
+		{"5x", 0, true},  // unknown unit
+		{"-5d", 0, true}, // negative, extended unit
+		{"-5h", 0, true}, // negative, Go unit
+		{"", 0, true},    // empty
 		{"garbage", 0, true},
 	}
 

internal/vaultik/verify.go

@@ -344,12 +344,8 @@ func (v *Vaultik) verifyBlob(blobInfo snapshot.BlobInfo, db *sql.DB) error {
 		return fmt.Errorf("failed to get decryptor: %w", err)
 	}
 
-	// Hash the encrypted blob data as it streams through to decryption
-	blobHasher := sha256.New()
-	teeReader := io.TeeReader(reader, blobHasher)
-
-	// Decrypt blob (reading through teeReader to hash encrypted data)
-	decryptedReader, err := decryptor.DecryptStream(teeReader)
+	// Decrypt blob
+	decryptedReader, err := decryptor.DecryptStream(reader)
 	if err != nil {
 		return fmt.Errorf("failed to decrypt: %w", err)
 	}
@@ -361,12 +357,19 @@ func (v *Vaultik) verifyBlob(blobInfo snapshot.BlobInfo, db *sql.DB) error {
 	}
 	defer decompressor.Close()
 
-	chunkCount, err := v.verifyBlobChunks(db, blobInfo.Hash, decompressor)
+	// A blob's hash — its remote name — is the double SHA256 of its
+	// decompressed plaintext (see blobgen.Writer.Sum256), not of the
+	// encrypted bytes. Hash the plaintext as chunk verification streams
+	// it, then compare on completion.
+	plaintextHasher := sha256.New()
+	hashedStream := io.TeeReader(decompressor, plaintextHasher)
+
+	chunkCount, err := v.verifyBlobChunks(db, blobInfo.Hash, hashedStream)
 	if err != nil {
 		return err
 	}
 
-	err = v.verifyBlobFinalIntegrity(decompressor, blobHasher, blobInfo.Hash)
+	err = v.verifyBlobFinalIntegrity(hashedStream, plaintextHasher, blobInfo.Hash)
 	if err != nil {
 		return err
 	}
@@ -470,14 +473,13 @@ func (v *Vaultik) verifyBlobChunks(
 }
 
 // verifyBlobFinalIntegrity checks that no trailing data exists in the
-// decompressed stream and that the encrypted blob hash matches the
-// expected value.
+// decompressed stream and that the blob hash matches the expected value.
 func (v *Vaultik) verifyBlobFinalIntegrity(
-	decompressor io.Reader, blobHasher hash.Hash, expectedHash string,
+	plaintext io.Reader, plaintextHasher hash.Hash, expectedHash string,
 ) error {
 	// Verify no remaining data in blob - if the chunk list is accurate,
 	// the blob should be fully consumed.
-	remaining, err := io.Copy(io.Discard, decompressor)
+	remaining, err := io.Copy(io.Discard, plaintext)
 	if err != nil {
 		return fmt.Errorf("failed to check for remaining blob data: %w", err)
 	}
@@ -486,8 +488,11 @@ func (v *Vaultik) verifyBlobFinalIntegrity(
 		return fmt.Errorf("%w: %d bytes", errTrailingBlobData, remaining)
 	}
 
-	// Verify blob hash matches the encrypted data we downloaded
-	calculatedBlobHash := hex.EncodeToString(blobHasher.Sum(nil))
+	// The blob hash is the double SHA256 of its plaintext content.
+	firstHash := plaintextHasher.Sum(nil)
+	secondHash := sha256.Sum256(firstHash)
+	calculatedBlobHash := hex.EncodeToString(secondHash[:])
+
 	if calculatedBlobHash != expectedHash {
 		return fmt.Errorf("%w: calculated %s, expected %s",
 			errBlobHashMismatch, calculatedBlobHash, expectedHash)