Report blobs shallow verify could not check apart from missing ones (closes #318)

Shallow snapshot verify counted every error from checking a blob or the
encrypted database as "missing" and printed the error nowhere, so a
permission error or an S3 403 read as data loss. Now only a not-found
answer from storage counts as missing. Any other error is reported as
could not be checked, with the error storage returned, in the text
report and under --json (the new unchecked list and
database_check_error field), and the run fails. Under --quiet, which
drops the report, each of those errors is logged as a warning on
stderr.

The database check moved into its own small function because the verify
function was at the linter's length limit.

Model: opus-5-5

internal/vaultik/destination_validation_test.go

@@ -161,13 +161,14 @@ func TestVerifyManifestBlobsRejectsShortHash(t *testing.T) {
 		Blobs: []snapshot.BlobInfo{{Hash: "abc", CompressedSize: 1}},
 	}
 
-	verified, missing, mismatched, missingSize, err :=
+	verified, missing, mismatched, missingSize, unchecked, err :=
 		v.verifyManifestBlobs(manifest, &VerifyOptions{JSON: true})
 	require.ErrorIs(t, err, errInvalidBlobHash)
 	require.Zero(t, verified)
 	require.Zero(t, missing)
 	require.Zero(t, mismatched)
 	require.Zero(t, missingSize)
+	require.Empty(t, unchecked)
 }
 
 // TestVerifyBlobChunksRejectsNegativeLength proves a blob_chunks row with a

internal/vaultik/restore.go

@@ -309,22 +309,11 @@ func (v *Vaultik) restoreAllFiles(
 		return nil, err
 	}
 
-	plan, unplanned, err := newRestorePlan(
-		v.ctx, repos, files, chunkToBlobMap, blobIDToHash)
+	plan, err := newRestorePlan(v.ctx, repos, files, chunkToBlobMap, blobIDToHash)
 	if err != nil {
 		return nil, fmt.Errorf("building restore plan: %w", err)
 	}
 
-	// Ranging over files rather than the map reports them in a stable order.
-	for _, file := range files {
-		if planErr, ok := unplanned[file.ID]; ok {
-			err = v.handleRestoreFileError(plan, opts, result, file, file.ID, planErr)
-			if err != nil {
-				return nil, err
-			}
-		}
-	}
-
 	filesByID, totalBytesExpected := indexRestoreFiles(files)
 
 	v.UI.Beginf("Restoring %s files (%s) to %s.",

internal/vaultik/restore_malformed_db_test.go

@@ -61,8 +61,8 @@ func craftedFile(
 }
 
 // TestRestoreShortChunkHashInNoBlob proves a file whose short chunk hash
-// has no blob_chunks row is left out of the restore plan with an error,
-// and fails the chunk write with an error.
+// has no blob_chunks row fails restore planning and the chunk write with
+// an error.
 func TestRestoreShortChunkHashInNoBlob(t *testing.T) {
 	t.Parallel()
 
@@ -77,11 +77,9 @@ func TestRestoreShortChunkHashInNoBlob(t *testing.T) {
 	chunkToBlobMap, err := v.buildChunkToBlobMap(ctx, repos)
 	require.NoError(t, err)
 
-	plan, unplanned, err := newRestorePlan(ctx, repos, []*database.File{file},
+	_, err = newRestorePlan(ctx, repos, []*database.File{file},
 		chunkToBlobMap, map[string]string{})
-	require.NoError(t, err)
-	require.ErrorIs(t, unplanned[file.ID], errPlanChunkMissing)
-	require.False(t, plan.hasPending())
+	require.ErrorIs(t, err, errPlanChunkMissing)
 
 	fileChunks, err := repos.FileChunks.GetByFileID(ctx, file.ID)
 	require.NoError(t, err)

internal/vaultik/restore_plan.go

@@ -41,25 +41,20 @@ type restorePlan struct {
 
 // newRestorePlan builds the file→blob index for the given files. Files
 // whose chunks reference no blobs (symlinks, directories) start in the
-// ready queue immediately. A file with a chunk that no blob holds cannot
-// be restored: it is left out of the plan and returned, by ID, with the
-// reason.
+// ready queue immediately.
 func newRestorePlan(
 	ctx context.Context,
 	repos *database.Repositories,
 	files []*database.File,
 	chunkToBlobMap map[string]*database.BlobChunk,
 	blobIDToHash map[string]string,
-) (*restorePlan, map[types.FileID]error, error) {
+) (*restorePlan, error) {
 	p := &restorePlan{
 		fileBlobs: make(map[types.FileID]map[string]struct{}, len(files)),
 		blobFiles: make(map[string]map[types.FileID]struct{}),
 		ready:     make([]types.FileID, 0, len(files)),
 		cached:    make(map[string]struct{}),
 	}
-	unplanned := make(map[types.FileID]error)
-
-nextFile:
 	for _, f := range files {
 		if f.IsSymlink() || f.Mode&uint32(os.ModeDir) != 0 {
 			// No chunks to fetch — restore can run immediately.
@@ -71,7 +66,7 @@ nextFile:
 
 		fileChunks, err := repos.FileChunks.GetByFileID(ctx, f.ID)
 		if err != nil {
-			return nil, nil, fmt.Errorf("planning %s: %w", f.Path, err)
+			return nil, fmt.Errorf("planning %s: %w", f.Path, err)
 		}
 
 		blobs := make(map[string]struct{})
@@ -79,18 +74,14 @@ nextFile:
 		for _, fc := range fileChunks {
 			bc, ok := chunkToBlobMap[fc.ChunkHash.String()]
 			if !ok {
-				unplanned[f.ID] = fmt.Errorf("%w: %s",
-					errPlanChunkMissing, shortHash(fc.ChunkHash.String()))
-
-				continue nextFile
+				return nil, fmt.Errorf("planning %s: %w: %s",
+					f.Path, errPlanChunkMissing, shortHash(fc.ChunkHash.String()))
 			}
 
 			hash, ok := blobIDToHash[bc.BlobID.String()]
 			if !ok {
-				unplanned[f.ID] = fmt.Errorf("%w: %s",
-					errPlanBlobIDMissing, bc.BlobID)
-
-				continue nextFile
+				return nil, fmt.Errorf("planning %s: %w: %s",
+					f.Path, errPlanBlobIDMissing, bc.BlobID)
 			}
 
 			blobs[hash] = struct{}{}
@@ -112,7 +103,7 @@ nextFile:
 		}
 	}
 
-	return p, unplanned, nil
+	return p, nil
 }
 
 // markBlobCached records that the named blob is now resident in the

internal/vaultik/restore_skip_errors_test.go

@@ -28,8 +28,7 @@ const (
 )
 
 // missingBlobBackup is a snapshot of single-chunk files spread over two
-// blobs, with one of those blobs lost: deleted from the store, or missing
-// from the snapshot metadata.
+// blobs, with one of those blobs deleted from the store.
 type missingBlobBackup struct {
 	fs         afero.Fs
 	cfg        *config.Config
@@ -38,39 +37,20 @@ type missingBlobBackup struct {
 	restoreDir string
 	// files holds the original content by source path.
 	files map[string][]byte
-	// lost holds the source paths whose chunk is in the lost blob.
+	// lost holds the source paths whose chunk is in the deleted blob.
 	lost map[string]bool
 }
 
 // TestRestoreSkipErrorsSkipsFilesOfMissingBlob restores with SkipErrors
-// after one blob of a two-blob snapshot was deleted from the store.
+// after one blob of a two-blob snapshot was deleted. Every file stored in
+// that blob must be reported as failed and left absent, every other file
+// must be restored intact, and Restore must still return an error.
 func TestRestoreSkipErrorsSkipsFilesOfMissingBlob(t *testing.T) {
 	log.Initialize(log.Config{})
 	t.Parallel()
 
 	ctx := context.Background()
-	assertRestoreSkipsLostFiles(ctx, t, backupThenDeleteOneBlob(ctx, t))
-}
-
-// TestRestoreSkipErrorsSkipsFilesWithChunkInNoBlob restores with
-// SkipErrors a snapshot whose metadata lists chunks that no blob holds, as
-// earlier backup defects left behind.
-func TestRestoreSkipErrorsSkipsFilesWithChunkInNoBlob(t *testing.T) {
-	log.Initialize(log.Config{})
-	t.Parallel()
-
-	ctx := context.Background()
-	assertRestoreSkipsLostFiles(ctx, t, backupThenDropOneBlobFromMetadata(ctx, t))
-}
-
-// assertRestoreSkipsLostFiles restores backup with SkipErrors. Every file
-// stored in the lost blob must be reported as failed and left absent,
-// every other file must be restored intact, and Restore must still return
-// an error.
-func assertRestoreSkipsLostFiles(
-	ctx context.Context, t *testing.T, backup *missingBlobBackup,
-) {
-	t.Helper()
+	backup := backupThenDeleteOneBlob(ctx, t)
 
 	var out bytes.Buffer
 
@@ -92,14 +72,14 @@ func assertRestoreSkipsLostFiles(
 
 		if backup.lost[path] {
 			assert.Containsf(t, out.String(), path,
-				"%s needs the lost blob and must be reported", path)
+				"%s needs the deleted blob and must be reported", path)
 			assert.NoFileExists(t, restored)
 
 			continue
 		}
 
 		got, err := afero.ReadFile(backup.fs, restored)
-		require.NoErrorf(t, err, "%s does not need the lost blob", path)
+		require.NoErrorf(t, err, "%s does not need the deleted blob", path)
 		assert.Equalf(t, content, got, "%s restored with wrong content", path)
 	}
 }
@@ -123,30 +103,6 @@ func TestRestoreMissingBlobAbortsWithoutSkipErrors(t *testing.T) {
 	require.ErrorIs(t, err, storage.ErrNotFound)
 }
 
-// TestRestoreChunkInNoBlobAbortsWithoutSkipErrors checks that a chunk held
-// by no blob still ends the restore, before any file is written, when
-// SkipErrors is not set.
-func TestRestoreChunkInNoBlobAbortsWithoutSkipErrors(t *testing.T) {
-	log.Initialize(log.Config{})
-	t.Parallel()
-
-	ctx := context.Background()
-	backup := backupThenDropOneBlobFromMetadata(ctx, t)
-
-	v := newReaderVaultik(ctx, backup.cfg, backup.storer, nil, backup.fs)
-
-	err := v.Restore(&vaultik.RestoreOptions{
-		SnapshotID: backup.snapshotID,
-		TargetDir:  backup.restoreDir,
-	})
-
-	require.ErrorContains(t, err, "chunk missing from blob map")
-
-	for path := range backup.files {
-		assert.NoFileExists(t, filepath.Join(backup.restoreDir, path))
-	}
-}
-
 // backupThenDeleteOneBlob backs up missingBlobFileCount single-chunk
 // files, then deletes from the store the blob holding the first of them.
 func backupThenDeleteOneBlob(
@@ -154,54 +110,6 @@ func backupThenDeleteOneBlob(
 ) *missingBlobBackup {
 	t.Helper()
 
-	backup, db, lostBlob := backupSingleChunkFiles(ctx, t)
-	require.NoError(t, db.Close())
-
-	require.NoError(t, backup.storer.Delete(ctx, fmt.Sprintf(
-		"blobs/%s/%s/%s", lostBlob[:2], lostBlob[2:4], lostBlob)))
-
-	return backup
-}
-
-// backupThenDropOneBlobFromMetadata backs up missingBlobFileCount
-// single-chunk files, then removes the blob holding the first of them from
-// the snapshot and exports the snapshot metadata again. The exported
-// metadata then lists chunks that no blob holds.
-func backupThenDropOneBlobFromMetadata(
-	ctx context.Context, t *testing.T,
-) *missingBlobBackup {
-	t.Helper()
-
-	backup, db, lostBlob := backupSingleChunkFiles(ctx, t)
-
-	// The uploads row refers to the blob row, so it would keep the export
-	// from deleting it.
-	for _, query := range []string{
-		"DELETE FROM snapshot_blobs WHERE blob_hash = ?",
-		"DELETE FROM uploads WHERE blob_hash = ?",
-	} {
-		_, err := db.Conn().ExecContext(ctx, query, lostBlob)
-		require.NoError(t, err)
-	}
-
-	sm := newFaultSnapshotManager(
-		backup.fs, backup.storer, backup.cfg, database.NewRepositories(db))
-	require.NoError(t,
-		sm.ExportSnapshotMetadata(ctx, db.Path(), backup.snapshotID))
-	require.NoError(t, db.Close())
-
-	return backup
-}
-
-// backupSingleChunkFiles backs up missingBlobFileCount single-chunk files.
-// It returns the backup, with lost naming the files stored in the same
-// blob as the first of them, the still open local index, and the hash of
-// that blob.
-func backupSingleChunkFiles(
-	ctx context.Context, t *testing.T,
-) (*missingBlobBackup, *database.DB, string) {
-	t.Helper()
-
 	fs := afero.NewOsFs()
 	tempDir := t.TempDir()
 	dataDir := filepath.Join(tempDir, "src")
@@ -235,11 +143,16 @@ func backupSingleChunkFiles(
 		blobOfFile[path] = blobHashOfSingleChunkFile(ctx, t, repos, path)
 	}
 
-	lostBlob := blobOfFile[filepath.Join(dataDir, "file-00.bin")]
+	require.NoError(t, db.Close())
+
+	deleted := blobOfFile[filepath.Join(dataDir, "file-00.bin")]
+	require.NoError(t, storer.Delete(ctx, fmt.Sprintf(
+		"blobs/%s/%s/%s", deleted[:2], deleted[2:4], deleted)))
+
 	lost := make(map[string]bool)
 
 	for path, hash := range blobOfFile {
-		if hash == lostBlob {
+		if hash == deleted {
 			lost[path] = true
 		}
 	}
@@ -255,7 +168,7 @@ func backupSingleChunkFiles(
 		restoreDir: filepath.Join(tempDir, "restored"),
 		files:      files,
 		lost:       lost,
-	}, db, lostBlob
+	}
 }
 
 // blobHashOfSingleChunkFile returns the hash of the blob holding the one

internal/vaultik/shallow_verify_test.go

@@ -4,15 +4,20 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
+	"errors"
+	"fmt"
 	"io"
 	"os"
+	"path"
 	"path/filepath"
+	"slices"
 	"testing"
 
 	"github.com/spf13/afero"
 	"github.com/stretchr/testify/require"
 	"sneak.berlin/go/vaultik/internal/log"
 	"sneak.berlin/go/vaultik/internal/snapshot"
+	"sneak.berlin/go/vaultik/internal/storage"
 	"sneak.berlin/go/vaultik/internal/ui"
 	"sneak.berlin/go/vaultik/internal/vaultik"
 )
@@ -151,6 +156,224 @@ func TestShallowVerifyDetectsMissingDatabase(t *testing.T) {
 		"shallow verify must fail when db.zst.age is absent")
 }
 
+// errStatDenied stands in for any storage error other than not-found: a
+// permission error, an S3 403, a dropped connection.
+var errStatDenied = errors.New("injected stat failure")
+
+// statFailingStorer fails Stat with errStatDenied for the keys in
+// failKeys and passes every other call to the wrapped Storer.
+type statFailingStorer struct {
+	storage.Storer
+
+	failKeys []string
+}
+
+func (s statFailingStorer) Stat(
+	ctx context.Context, key string,
+) (*storage.ObjectInfo, error) {
+	if slices.Contains(s.failKeys, key) {
+		return nil, fmt.Errorf("stat %q: %w", key, errStatDenied)
+	}
+
+	return s.Storer.Stat(ctx, key)
+}
+
+// TestShallowVerifyReportsStatErrorsApartFromMissing backs up a real
+// snapshot, deletes one blob, and makes storage fail Stat with an error
+// other than not-found for a second blob and for the encrypted database.
+// Only the deleted blob may be counted as missing. The second blob and
+// the database must be reported as could not be checked, with the error
+// storage returned, and verify must fail, in the text output and under
+// --json.
+func TestShallowVerifyReportsStatErrorsApartFromMissing(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(32 * 1024)
+	maxBlobSize := int64(128 * 1024)
+
+	// Random content, so the snapshot spans several blobs.
+	require.NoError(t, fs.MkdirAll(dataDir, 0o755))
+	appendRandomBytes(t, fs, map[string][]byte{},
+		filepath.Join(dataDir, "data.bin"), maxBlobSize*4)
+
+	ctx := context.Background()
+
+	cfg, storer, snapshotID := runFileStorageBackup(
+		ctx, t, fs, dataDir, storeDir, dbPath, chunkSize, maxBlobSize)
+
+	blobKeys := storedBlobKeys(t, storeDir)
+	require.GreaterOrEqual(t, len(blobKeys), 2, "expected at least two blobs")
+
+	missingKey, uncheckedKey := blobKeys[0], blobKeys[1]
+	missingHash, uncheckedHash := path.Base(missingKey), path.Base(uncheckedKey)
+
+	require.NoError(t, os.Remove(filepath.Join(storeDir, missingKey)))
+
+	dbKey := "metadata/" + snapshot.RemoteSnapshotKey(snapshotID) + "/db.zst.age"
+	failing := statFailingStorer{
+		Storer:   storer,
+		failKeys: []string{uncheckedKey, dbKey},
+	}
+
+	newVerifier := func(out io.Writer) *vaultik.Vaultik {
+		v := &vaultik.Vaultik{
+			Config:  cfg,
+			Storage: failing,
+			Fs:      fs,
+			Stdout:  out,
+			Stderr:  io.Discard,
+			UI:      ui.NewWithColor(io.Discard, false),
+		}
+		v.SetContext(ctx)
+
+		return v
+	}
+
+	var out bytes.Buffer
+
+	err := newVerifier(&out).VerifySnapshotWithOptions(
+		snapshotID, &vaultik.VerifyOptions{JSON: true})
+	require.Error(t, err)
+
+	result := decodeVerifyResult(t, out.Bytes())
+	require.Equal(t, "failed", result.Status)
+	require.Equal(t, 1, result.Missing, "only the deleted blob is missing")
+	require.Equal(t, result.BlobCount-2, result.Verified)
+	require.Len(t, result.Unchecked, 1)
+	require.Equal(t, uncheckedHash, result.Unchecked[0].Hash)
+	require.Contains(t, result.Unchecked[0].Error, errStatDenied.Error())
+	require.False(t, result.DatabaseMissing,
+		"a database that could not be checked is not missing")
+	require.Contains(t, result.DatabaseCheckError, errStatDenied.Error())
+
+	out.Reset()
+	err = newVerifier(&out).VerifySnapshotWithOptions(
+		snapshotID, &vaultik.VerifyOptions{})
+	require.Error(t, err)
+
+	text := out.String()
+	require.Contains(t, text, "Missing: "+missingHash)
+	require.NotContains(t, text, "Missing: "+uncheckedHash)
+	require.Contains(t, text, "Could not check: "+uncheckedHash)
+	require.Contains(t, text, "Encrypted database:       could not be checked")
+	require.Contains(t, text, errStatDenied.Error())
+	require.Contains(t, text, "FAILED")
+}
+
+// TestShallowVerifyQuietFailsOnStatErrorAlone backs up a healthy snapshot,
+// then makes storage fail Stat, with an error other than not-found, for
+// one blob alone and then for the encrypted database alone. Each run must
+// fail verify, and under --quiet, which drops the report, the error
+// storage returned must still reach stderr.
+//
+//nolint:paralleltest // captureProcessStderr replaces os.Stderr
+func TestShallowVerifyQuietFailsOnStatErrorAlone(t *testing.T) {
+	log.Initialize(log.Config{})
+
+	fs := afero.NewOsFs()
+	tempDir := t.TempDir()
+
+	dataDir := filepath.Join(tempDir, "source")
+	storeDir := filepath.Join(tempDir, "remote")
+	dbPath := filepath.Join(tempDir, "index.sqlite")
+
+	chunkSize := int64(32 * 1024)
+	maxBlobSize := int64(128 * 1024)
+
+	require.NoError(t, fs.MkdirAll(dataDir, 0o755))
+	require.NoError(t, afero.WriteFile(fs,
+		filepath.Join(dataDir, "data.bin"),
+		bytesPattern("shallow-quiet-", int(maxBlobSize*2)), 0o644))
+
+	ctx := context.Background()
+
+	cfg, storer, snapshotID := runFileStorageBackup(
+		ctx, t, fs, dataDir, storeDir, dbPath, chunkSize, maxBlobSize)
+
+	newQuietVerifier := func(s storage.Storer) *vaultik.Vaultik {
+		v := &vaultik.Vaultik{
+			Config:  cfg,
+			Storage: s,
+			Fs:      fs,
+			Stdout:  io.Discard,
+			Stderr:  io.Discard,
+			UI:      ui.NewWithColor(io.Discard, false),
+		}
+		v.SetContext(ctx)
+		v.UI.SetQuiet(true)
+
+		return v
+	}
+
+	require.NoError(t,
+		newQuietVerifier(storer).VerifySnapshotWithOptions(
+			snapshotID, &vaultik.VerifyOptions{}),
+		"shallow verify should pass on a healthy snapshot")
+
+	blobKeys := storedBlobKeys(t, storeDir)
+	require.NotEmpty(t, blobKeys)
+
+	dbKey := "metadata/" + snapshot.RemoteSnapshotKey(snapshotID) + "/db.zst.age"
+
+	for _, failKey := range []string{blobKeys[0], dbKey} {
+		v := newQuietVerifier(statFailingStorer{
+			Storer:   storer,
+			failKeys: []string{failKey},
+		})
+
+		var err error
+
+		stderr := captureProcessStderr(t, func() {
+			err = v.VerifySnapshotWithOptions(
+				snapshotID, &vaultik.VerifyOptions{})
+		})
+
+		require.Error(t, err,
+			"verify must fail when %s could not be checked", failKey)
+		require.Contains(t, stderr, errStatDenied.Error(),
+			"under --quiet the error for %s must still reach stderr", failKey)
+	}
+}
+
+// storedBlobKeys returns the storage key of every blob file under
+// storeDir, sorted.
+func storedBlobKeys(t *testing.T, storeDir string) []string {
+	t.Helper()
+
+	var keys []string
+
+	err := filepath.Walk(filepath.Join(storeDir, "blobs"),
+		func(p string, info os.FileInfo, err error) error {
+			if err != nil {
+				return err
+			}
+
+			if info.IsDir() {
+				return nil
+			}
+
+			rel, err := filepath.Rel(storeDir, p)
+			if err != nil {
+				return err
+			}
+
+			keys = append(keys, filepath.ToSlash(rel))
+
+			return nil
+		})
+	require.NoError(t, err)
+
+	return keys
+}
+
 // growOneBlob appends bytes to the first blob file found under blobsDir,
 // changing its on-disk size so it no longer matches the manifest.
 func growOneBlob(t *testing.T, fs afero.Fs, blobsDir string) {

internal/vaultik/snapshot.go

@@ -14,6 +14,7 @@ import (
 
 	"sneak.berlin/go/vaultik/internal/log"
 	"sneak.berlin/go/vaultik/internal/snapshot"
+	"sneak.berlin/go/vaultik/internal/storage"
 	"sneak.berlin/go/vaultik/internal/types"
 )
 
@@ -774,18 +775,10 @@ func (v *Vaultik) VerifySnapshotWithOptions(
 		v.stdoutf("Checking blob presence and sizes...\n")
 	}
 
-	// A snapshot is only restorable if its encrypted database is present
-	// alongside the blobs. Shallow verify checks that the object exists; it
-	// does not decrypt it (that is deep verify's job).
-	dbPath := fmt.Sprintf("metadata/%s/db.zst.age", remoteKey)
+	v.checkSnapshotDatabase(remoteKey, result)
 
-	_, dbErr := v.Storage.Stat(v.ctx, dbPath)
-	if dbErr != nil {
-		result.DatabaseMissing = true
-	}
-
-	result.Verified, result.Missing, result.Mismatched, result.MissingSize, err =
-		v.verifyManifestBlobs(manifest, opts)
+	result.Verified, result.Missing, result.Mismatched, result.MissingSize,
+		result.Unchecked, err = v.verifyManifestBlobs(manifest, opts)
 	if err != nil {
 		if opts.JSON {
 			result.Status = verifyStatusFailed
@@ -822,25 +815,46 @@ func (v *Vaultik) printVerifyHeader(snapshotID string, opts *VerifyOptions) {
 	}
 }
 
+// checkSnapshotDatabase records in result whether the snapshot's
+// encrypted database is missing or could not be checked. A snapshot is
+// only restorable if its database is present alongside the blobs.
+// Shallow verify checks that the object exists; it does not decrypt it
+// (that is deep verify's job).
+func (v *Vaultik) checkSnapshotDatabase(remoteKey string, result *VerifyResult) {
+	dbPath := fmt.Sprintf("metadata/%s/db.zst.age", remoteKey)
+
+	_, err := v.Storage.Stat(v.ctx, dbPath)
+
+	switch {
+	case errors.Is(err, storage.ErrNotFound):
+		result.DatabaseMissing = true
+	case err != nil:
+		result.DatabaseCheckError = err.Error()
+	}
+}
+
 // verifyManifestBlobs checks that each blob in the manifest is present in
 // storage with the size the manifest records, returning the counts of
 // blobs that were present with the right size, absent, and present but the
-// wrong size, plus the total bytes of the absent blobs. It does not read
-// blob contents; deep verification (RunDeepVerify) does that. The size
-// comparison matches the deep path (see verifyBlobExistenceFromDB).
+// wrong size, the total bytes of the absent blobs, and the blobs it could
+// not check because storage returned an error other than not-found. It
+// does not read blob contents; deep verification (RunDeepVerify) does
+// that. The size comparison matches the deep path (see
+// verifyBlobExistenceFromDB).
 func (v *Vaultik) verifyManifestBlobs(
 	manifest *snapshot.Manifest, opts *VerifyOptions,
-) (int, int, int, int64, error) {
+) (int, int, int, int64, []UncheckedBlob, error) {
 	var (
 		verified, missing, mismatched int
 		missingSize                   int64
+		unchecked                     []UncheckedBlob
 	)
 
 	for _, blob := range manifest.Blobs {
 		// The manifest is unauthenticated, so its blob hashes are checked
 		// before being spliced into a storage path.
 		if !isBlobHash(blob.Hash) {
-			return 0, 0, 0, 0, fmt.Errorf("%w: %s",
+			return 0, 0, 0, 0, nil, fmt.Errorf("%w: %s",
 				errInvalidBlobHash, shortHash(blob.Hash))
 		}
 
@@ -849,7 +863,7 @@ func (v *Vaultik) verifyManifestBlobs(
 
 		stat, err := v.Storage.Stat(v.ctx, blobPath)
 		switch {
-		case err != nil:
+		case errors.Is(err, storage.ErrNotFound):
 			if !opts.JSON && !v.UI.Quiet() {
 				v.stdoutf("  Missing: %s (%s)\n",
 					blob.Hash, ubytes(blob.CompressedSize))
@@ -857,6 +871,13 @@ func (v *Vaultik) verifyManifestBlobs(
 
 			missing++
 			missingSize += blob.CompressedSize
+		case err != nil:
+			if !opts.JSON && !v.UI.Quiet() {
+				v.stdoutf("  Could not check: %s (%v)\n", blob.Hash, err)
+			}
+
+			unchecked = append(unchecked,
+				UncheckedBlob{Hash: blob.Hash, Error: err.Error()})
 		case stat.Size != blob.CompressedSize:
 			if !opts.JSON && !v.UI.Quiet() {
 				v.stdoutf("  Wrong size: %s (store has %s, manifest lists %s)\n",
@@ -869,7 +890,7 @@ func (v *Vaultik) verifyManifestBlobs(
 		}
 	}
 
-	return verified, missing, mismatched, missingSize, nil
+	return verified, missing, mismatched, missingSize, unchecked, nil
 }
 
 // formatVerifyResult outputs the final verification results as JSON or
@@ -890,9 +911,19 @@ func (v *Vaultik) formatVerifyResult(
 		return v.outputVerifyJSON(result)
 	}
 
-	// Under --quiet a failure is still returned, and the cli layer
-	// prints it on stderr.
-	if !v.UI.Quiet() {
+	// --quiet drops the report but not the errors storage returned, which
+	// are logged on stderr. A failure is still returned either way, and
+	// the cli layer prints it on stderr.
+	if v.UI.Quiet() {
+		for _, blob := range result.Unchecked {
+			log.Warn("Could not check blob", "blob", blob.Hash, "error", blob.Error)
+		}
+
+		if result.DatabaseCheckError != "" {
+			log.Warn("Could not check the encrypted database",
+				"snapshot", result.SnapshotID, "error", result.DatabaseCheckError)
+		}
+	} else {
 		v.printVerifySummary(result, failure)
 	}
 
@@ -918,10 +949,19 @@ func (v *Vaultik) printVerifySummary(result *VerifyResult, failure string) {
 		v.stdoutf("  Wrong size:               %d blobs\n", result.Mismatched)
 	}
 
+	if len(result.Unchecked) > 0 {
+		v.stdoutf("  Could not check:          %d blobs\n", len(result.Unchecked))
+	}
+
 	if result.DatabaseMissing {
 		v.stdoutf("  Encrypted database:       missing\n")
 	}
 
+	if result.DatabaseCheckError != "" {
+		v.stdoutf("  Encrypted database:       could not be checked (%s)\n",
+			result.DatabaseCheckError)
+	}
+
 	v.stdoutf("  Status:       ")
 
 	if failure != "" {
@@ -949,10 +989,19 @@ func shallowVerifyFailure(result *VerifyResult) string {
 			fmt.Sprintf("%d blobs have the wrong size", result.Mismatched))
 	}
 
+	if len(result.Unchecked) > 0 {
+		parts = append(parts, fmt.Sprintf("%d blobs could not be checked",
+			len(result.Unchecked)))
+	}
+
 	if result.DatabaseMissing {
 		parts = append(parts, "the encrypted database is missing")
 	}
 
+	if result.DatabaseCheckError != "" {
+		parts = append(parts, "the encrypted database could not be checked")
+	}
+
 	return strings.Join(parts, "; ")
 }
 

internal/vaultik/verify.go

@@ -57,11 +57,25 @@ type VerifyResult struct {
 	Missing     int    `json:"missing"`
 	MissingSize int64  `json:"missing_size,omitempty"`
 	Mismatched  int    `json:"mismatched,omitempty"`
+	// Unchecked lists the blobs shallow verify could not check, because
+	// storage answered with an error other than not-found, so whether
+	// they are present is unknown.
+	Unchecked []UncheckedBlob `json:"unchecked,omitempty"`
 	// DatabaseMissing is set by shallow verify when the snapshot's
 	// encrypted database (metadata/<key>/db.zst.age) is absent, which
 	// makes the snapshot unrestorable regardless of the blobs.
-	DatabaseMissing bool   `json:"database_missing,omitempty"`
-	ErrorMessage    string `json:"error,omitempty"`
+	DatabaseMissing bool `json:"database_missing,omitempty"`
+	// DatabaseCheckError is set by shallow verify to the error storage
+	// returned when the encrypted database could not be checked.
+	DatabaseCheckError string `json:"database_check_error,omitempty"`
+	ErrorMessage       string `json:"error,omitempty"`
+}
+
+// UncheckedBlob is a blob shallow verify could not check, with the error
+// storage returned for it.
+type UncheckedBlob struct {
+	Hash  string `json:"hash"`
+	Error string `json:"error"`
 }
 
 // deepVerifyFailure records a failure in the result and returns it appropriately