Update golangci-lint to v2.12.2 with canonical config (#62)

Updates golangci-lint to v2.12.2 everywhere it is pinned and installs the canonical `.golangci.yml`, then remediates every finding the new linter/config surfaces so `make check` is green.

## Version bump

- `Dockerfile` lint stage: `golangci/golangci-lint:v2.11.3-alpine` -> `v2.12.2-alpine` (digest-pinned, date comment updated)
- `Makefile` `deps` target: `go install` moved from the old v1 module path at `@latest` to the pinned `github.com/golangci/golangci-lint/v2/cmd/golangci-lint@v2.12.2`
- `.golangci.yml` replaced with the canonical config (v2 schema; settings under `linters.settings` so the thresholds actually apply; `default: all` with the standard six disables)
- `script/bootstrap` installs golangci-lint via the system package manager and carries no version pin, so it is unchanged
- CI (`.gitea/workflows/check.yml`) only runs `script/cibuild`, so it needed no change

## Lint remediation

The canonical config surfaced ~3,300 findings across 56k lines. All are fixed, behavior-preserving; incorporates and supersedes the per-package mechanical passes already merged to `main` (refs #61). Highlights:

- `err113`: dynamic errors replaced with package sentinels + `%w` wrapping; comparisons via `errors.Is`
- `goprintffuncname`: printf-style helpers renamed with an `f` suffix (`ui.Writer` message methods, `cli.ReportErrorf`, `database.Fatalf`) and all call sites updated
- `revive` stutter renames: `blob.Handler`, `blob.WithReader`, `blob.ChunkPosition`, `storage.URL`, `storage.Info`; missing doc comments added
- `contextcheck`/`noctx`: `context.Context` threaded through `blob.Packer` and the scanner call sites; context-aware `exec`/`sql` variants
- `funlen`/`cyclop`/`gocognit`/`dupl`: oversized and duplicated functions split into focused helpers (production and test code)
- tests: `t.Parallel()` added where safe (global logger init kept in the serial phase for `-race`), `t.TempDir()`/`t.Helper()` adopted, several suites converted to external test packages
- `gosec`: bounded integer conversions, `ReadHeaderTimeout` on the test HTTP server; remaining warnings suppressed per-site with justifications
- remaining `nolint` directives are rare, targeted, and each carries a reason (e.g. `nilnil` not-found contract in the repository layer, fx module globals, on-disk snake_case struct tags)
- removed the deprecated `log.LogOptions` alias (callers migrated to `log.Options`)

`make check` (tests with `-race`, lint, fmt-check) passes.

Co-authored-by: sneak <sneak@sneak.berlin>
Reviewed-on: #62
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>

internal/blobgen/compress.go

@@ -1,3 +1,6 @@
+// Package blobgen implements the blob data pipeline: streaming zstd
+// compression, age encryption, and SHA256 content hashing for blob
+// creation, plus the matching decrypt/decompress/verify reader.
 package blobgen
 
 import (
@@ -16,7 +19,9 @@ type CompressResult struct {
 }
 
 // CompressData compresses and encrypts data, returning the result with hash
-func CompressData(data []byte, compressionLevel int, recipients []string) (*CompressResult, error) {
+func CompressData(
+	data []byte, compressionLevel int, recipients []string,
+) (*CompressResult, error) {
 	var buf bytes.Buffer
 
 	// Create writer
@@ -47,8 +52,11 @@ func CompressData(data []byte, compressionLevel int, recipients []string) (*Comp
 	}, nil
 }
 
-// CompressStream compresses and encrypts from reader to writer, returning hash
-func CompressStream(dst io.Writer, src io.Reader, compressionLevel int, recipients []string) (written int64, hash string, err error) {
+// CompressStream compresses and encrypts from reader to writer, returning
+// the number of uncompressed bytes written and the content hash.
+func CompressStream(
+	dst io.Writer, src io.Reader, compressionLevel int, recipients []string,
+) (int64, string, error) {
 	// Create writer
 	w, err := NewWriter(dst, compressionLevel, recipients)
 	if err != nil {

internal/blobgen/compress_test.go

@@ -1,4 +1,4 @@
-package blobgen
+package blobgen_test
 
 import (
 	"bytes"
@@ -8,6 +8,7 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/vaultik/internal/blobgen"
 )
 
 // testRecipient is a static age recipient for tests.
@@ -19,11 +20,14 @@ const testRecipient = "age1cplgrwj77ta54dnmydvvmzn64ltk83ankxl5sww04mrtmu62kv3s8
 // the explicit Close() on the happy path combined with defer Close() would
 // cause a double close.
 func TestCompressStreamNoDoubleClose(t *testing.T) {
+	t.Parallel()
+
 	input := []byte("regression test data for issue #28 double-close fix")
 
 	var buf bytes.Buffer
 
-	written, hash, err := CompressStream(&buf, bytes.NewReader(input), 3, []string{testRecipient})
+	written, hash, err := blobgen.CompressStream(
+		&buf, bytes.NewReader(input), 3, []string{testRecipient})
 	require.NoError(t, err, "CompressStream should not return an error")
 	assert.Positive(t, written, "expected bytes written > 0")
 	assert.NotEmpty(t, hash, "expected non-empty hash")
@@ -33,13 +37,16 @@ func TestCompressStreamNoDoubleClose(t *testing.T) {
 // TestCompressStreamLargeInput exercises CompressStream with a larger payload
 // to ensure no double-close issues surface under heavier I/O.
 func TestCompressStreamLargeInput(t *testing.T) {
+	t.Parallel()
+
 	data := make([]byte, 512*1024) // 512 KB
 	_, err := rand.Read(data)
 	require.NoError(t, err)
 
 	var buf bytes.Buffer
 
-	written, hash, err := CompressStream(&buf, bytes.NewReader(data), 3, []string{testRecipient})
+	written, hash, err := blobgen.CompressStream(
+		&buf, bytes.NewReader(data), 3, []string{testRecipient})
 	require.NoError(t, err)
 	assert.Positive(t, written)
 	assert.NotEmpty(t, hash)
@@ -48,9 +55,12 @@ func TestCompressStreamLargeInput(t *testing.T) {
 // TestCompressStreamEmptyInput verifies CompressStream handles empty input
 // without double-close issues.
 func TestCompressStreamEmptyInput(t *testing.T) {
+	t.Parallel()
+
 	var buf bytes.Buffer
 
-	_, hash, err := CompressStream(&buf, strings.NewReader(""), 3, []string{testRecipient})
+	_, hash, err := blobgen.CompressStream(
+		&buf, strings.NewReader(""), 3, []string{testRecipient})
 	require.NoError(t, err)
 	assert.NotEmpty(t, hash)
 }
@@ -58,8 +68,11 @@ func TestCompressStreamEmptyInput(t *testing.T) {
 // TestCompressDataNoDoubleClose mirrors the stream test for CompressData,
 // ensuring the explicit Close + error-path Close pattern is also safe.
 func TestCompressDataNoDoubleClose(t *testing.T) {
+	t.Parallel()
+
 	input := []byte("CompressData regression test for double-close")
-	result, err := CompressData(input, 3, []string{testRecipient})
+
+	result, err := blobgen.CompressData(input, 3, []string{testRecipient})
 	require.NoError(t, err)
 	assert.Positive(t, result.CompressedSize)
 	assert.Equal(t, result.UncompressedSize, int64(len(input)))

internal/blobgen/reader.go

@@ -50,8 +50,8 @@ func NewReader(r io.Reader, identity age.Identity) (*Reader, error) {
 }
 
 // Read implements io.Reader
-func (r *Reader) Read(p []byte) (n int, err error) {
-	n, err = r.teeReader.Read(p)
+func (r *Reader) Read(p []byte) (int, error) {
+	n, err := r.teeReader.Read(p)
 	r.bytesRead += int64(n)
 
 	return n, err

internal/blobgen/writer.go

@@ -2,6 +2,7 @@ package blobgen
 
 import (
 	"crypto/sha256"
+	"errors"
 	"fmt"
 	"hash"
 	"io"
@@ -11,6 +12,21 @@ import (
 	"github.com/klauspost/compress/zstd"
 )
 
+// Zstd compression level bounds accepted by NewWriter.
+const (
+	minCompressionLevel = 1
+	maxCompressionLevel = 19
+)
+
+// reservedCompressionCPUs is how many CPUs are left free of zstd
+// compression work for I/O and hashing.
+const reservedCompressionCPUs = 2
+
+// ErrInvalidCompressionLevel is returned when the zstd compression level
+// is outside the accepted 1-19 range.
+var ErrInvalidCompressionLevel = errors.New(
+	"invalid compression level: must be between 1 and 19")
+
 // Writer wraps compression and encryption with SHA256 hashing.
 // Data flows: input -> tee(hasher, compressor -> encryptor -> destination)
 // The hash is computed on the uncompressed input for deterministic content-addressing.
@@ -23,9 +39,12 @@ type Writer struct {
 	bytesWritten     int64
 }
 
-// NewWriter creates a new Writer that compresses, encrypts, and hashes data.
-// The hash is computed on the uncompressed input for deterministic content-addressing.
-func NewWriter(w io.Writer, compressionLevel int, recipients []string) (*Writer, error) {
+// NewWriter creates a new Writer that compresses, encrypts, and hashes
+// data. The hash is computed on the uncompressed input for deterministic
+// content-addressing.
+func NewWriter(
+	w io.Writer, compressionLevel int, recipients []string,
+) (*Writer, error) {
 	// Validate compression level
 	err := validateCompressionLevel(compressionLevel)
 	if err != nil {
@@ -54,7 +73,7 @@ func NewWriter(w io.Writer, compressionLevel int, recipients []string) (*Writer,
 	}
 
 	// Calculate compression concurrency: CPUs - 2, minimum 1
-	concurrency := max(runtime.NumCPU()-2, 1)
+	concurrency := max(runtime.NumCPU()-reservedCompressionCPUs, 1)
 
 	// Create compression writer with encryption as destination
 	compressor, err := zstd.NewWriter(encWriter,
@@ -80,8 +99,8 @@ func NewWriter(w io.Writer, compressionLevel int, recipients []string) (*Writer,
 }
 
 // Write implements io.Writer
-func (w *Writer) Write(p []byte) (n int, err error) {
-	n, err = w.teeWriter.Write(p)
+func (w *Writer) Write(p []byte) (int, error) {
+	n, err := w.teeWriter.Write(p)
 	w.bytesWritten += int64(n)
 
 	return n, err
@@ -124,9 +143,10 @@ func (w *Writer) BytesWritten() int64 {
 
 func validateCompressionLevel(level int) error {
 	// Zstd compression levels: 1-19 (default is 3)
-	// SpeedFastest = 1, SpeedDefault = 3, SpeedBetterCompression = 7, SpeedBestCompression = 11
-	if level < 1 || level > 19 {
-		return fmt.Errorf("invalid compression level %d: must be between 1 and 19", level)
+	// SpeedFastest = 1, SpeedDefault = 3, SpeedBetterCompression = 7,
+	// SpeedBestCompression = 11
+	if level < minCompressionLevel || level > maxCompressionLevel {
+		return fmt.Errorf("%w: got %d", ErrInvalidCompressionLevel, level)
 	}
 
 	return nil

internal/blobgen/writer_test.go

@@ -1,4 +1,4 @@
-package blobgen
+package blobgen_test
 
 import (
 	"bytes"
@@ -9,12 +9,15 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/vaultik/internal/blobgen"
 )
 
 // TestWriterHashIsDoubleHash verifies that Writer.Sum256() returns
 // the double hash SHA256(SHA256(plaintext)) for security.
 // Double hashing prevents attackers from confirming existence of known content.
 func TestWriterHashIsDoubleHash(t *testing.T) {
+	t.Parallel()
+
 	// Test data - random data that doesn't compress well
 	testData := make([]byte, 1024*1024) // 1MB
 	_, err := rand.Read(testData)
@@ -27,7 +30,7 @@ func TestWriterHashIsDoubleHash(t *testing.T) {
 	var encryptedBuf bytes.Buffer
 
 	// Create blobgen writer
-	writer, err := NewWriter(&encryptedBuf, 3, []string{testRecipient})
+	writer, err := blobgen.NewWriter(&encryptedBuf, 3, []string{testRecipient})
 	require.NoError(t, err)
 
 	// Write test data
@@ -67,6 +70,8 @@ func TestWriterHashIsDoubleHash(t *testing.T) {
 // TestWriterDeterministicHash verifies that the same input always produces
 // the same hash, even with non-deterministic encryption.
 func TestWriterDeterministicHash(t *testing.T) {
+	t.Parallel()
+
 	// Test data
 	testData := []byte("Hello, World! This is test data for deterministic hashing.")
 
@@ -76,13 +81,13 @@ func TestWriterDeterministicHash(t *testing.T) {
 	// Create two writers and verify they produce the same hash
 	var buf1, buf2 bytes.Buffer
 
-	writer1, err := NewWriter(&buf1, 3, []string{testRecipient})
+	writer1, err := blobgen.NewWriter(&buf1, 3, []string{testRecipient})
 	require.NoError(t, err)
 	_, err = writer1.Write(testData)
 	require.NoError(t, err)
 	require.NoError(t, writer1.Close())
 
-	writer2, err := NewWriter(&buf2, 3, []string{testRecipient})
+	writer2, err := blobgen.NewWriter(&buf2, 3, []string{testRecipient})
 	require.NoError(t, err)
 	_, err = writer2.Write(testData)
 	require.NoError(t, err)