Make the golangci-lint settings take effect: v2 config layout, linter pinned at v2.12.2 (closes #10)

golangci-lint v2 ignores a top-level linters-settings block without a
warning, so limits such as the 88-column line length were never
applied. .golangci.yml is now the canonical copy from sneak/prompts,
verbatim, which keeps its settings under linters.settings and also
configures depguard and gomodguard_v2. golangci-lint is pinned at
v2.12.2 by commit in the Dockerfile and script/bootstrap. The long
lines in attrsum.go are rewrapped and one nolint directive moves to
its own line; behaviour is unchanged.

Model: opus-5-5

.golangci.yml

@@ -1,21 +1,30 @@
 version: "2"
 
+# Config schema uses the golangci-lint v2 layout (settings live under
+# linters.settings, not top-level linters-settings) so that the
+# thresholds below are actually applied by golangci-lint >= v2.
+
 run:
   timeout: 5m
   modules-download-mode: readonly
 
 linters:
   default: all
+  enable:
+    # Successor to the deprecated gomodguard. Named explicitly, rather than
+    # left to `default: all`, because it carries the module policy below.
+    - gomodguard_v2
   disable:
     # Genuinely incompatible with project patterns
     - exhaustruct      # Requires all struct fields
-    - depguard         # Dependency allow/block lists
     - godot            # Requires comments to end with periods
-    - wsl              # Deprecated, replaced by wsl_v5
     - wrapcheck        # Too verbose for internal packages
     - varnamelen       # Short names like db, id are idiomatic Go
-
-linters-settings:
+    # Deprecated: the warning is attached to the old name, so it is
+    # silenced by disabling that name, not by enabling the successor.
+    - wsl              # Deprecated, replaced by wsl_v5
+    - gomodguard       # Deprecated, replaced by gomodguard_v2
+  settings:
     lll:
       line-length: 88
     funlen:
@@ -25,8 +34,65 @@ linters-settings:
       max-complexity: 15
     dupl:
       threshold: 100
+    depguard:
+      # Test-support code must not be compiled into the shipped binary. A
+      # test-support package exists to hand a test privileges the program
+      # itself must never have, so a file that is not a test must not import
+      # one. Test files, and the files inside a package whose directory name
+      # ends in `test`, are where that code belongs, and are exempt.
+      #
+      # The deny list below is the one part of this file a repository is
+      # expected to extend, and the only part it may. depguard matches an
+      # import path against a list of prefixes, so it cannot be told "any path
+      # whose last segment ends in test"; a repository's own test-support
+      # packages have to be named here one at a time, by full import path,
+      # under a module path that differs from repository to repository. Add
+      # them; change nothing else.
+      rules:
+        test-support:
+          list-mode: lax
+          files:
+            - "$all"
+            - "!$test"
+            - "!**/*test/**"
+          deny:
+            - pkg: net/http/httptest
+              desc: >-
+                Test-support code belongs in test files and in packages whose
+                directory name ends in test, not in the shipped binary.
+    # Only decisions already recorded in the Go package defaults are
+    # listed here. Every entry matches the module path exactly.
+    gomodguard_v2:
+      blocked:
+        - module: github.com/rs/zerolog
+          recommendations:
+            - log/slog
+          reason: "Structured logging is stdlib log/slog."
+        # One entry per pre-fork module path, because the later releases
+        # are separate paths. A prefix match would be shorter but would
+        # also reach github.com/go-redis/redismock, the test double for
+        # the successor these entries recommend.
+        - module: github.com/go-redis/redis
+          recommendations:
+            - github.com/redis/go-redis/v9
+          reason: "Pre-fork module; use the maintained go-redis v9."
+        - module: github.com/go-redis/redis/v7
+          recommendations:
+            - github.com/redis/go-redis/v9
+          reason: "Pre-fork module; use the maintained go-redis v9."
+        - module: github.com/go-redis/redis/v8
+          recommendations:
+            - github.com/redis/go-redis/v9
+          reason: "Pre-fork module; use the maintained go-redis v9."
+        - module: github.com/sergi/go-diff
+          recommendations:
+            - github.com/aymanbagabas/go-udiff
+          reason: "No unified diff output; use go-udiff."
+        - module: github.com/hexops/gotextdiff
+          recommendations:
+            - github.com/aymanbagabas/go-udiff
+          reason: "Unmaintained fork; use go-udiff."
 
 issues:
-  exclude-use-default: false
   max-issues-per-linter: 0
   max-same-issues: 0

Dockerfile

@@ -4,8 +4,8 @@ FROM golang@sha256:f6751d823c26342f9506c03797d2527668d095b0a15f1862cddb4d927a7a4
 
 RUN apk add --no-cache git make gcc musl-dev binutils-gold
 
-# golangci-lint v2.10.1
-RUN go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@5d1e709b7be35cb2025444e19de266b056b7b7ee
+# golangci-lint v2.12.2, 2026-10-05
+RUN go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@c0d3ddc9cf3faa61a4e378e879ece580256d76e5
 # goimports v0.42.0
 RUN go install golang.org/x/tools/cmd/goimports@009367f5c17a8d4c45a961a3a509277190a9a6f0
 

TODO.md

@@ -24,6 +24,11 @@ today) with lint, fmt, fmt-check, check, and hooks targets.
 
 # Completed Steps
 
+* 2026-10-05: golangci-lint settings take effect: canonical
+    `.golangci.yml` (v2 layout, settings under `linters.settings`),
+    golangci-lint pinned at v2.12.2 in `Dockerfile` and
+    `script/bootstrap`, and the code fixed for what the settings now
+    report (long lines in `attrsum.go` rewrapped)
 * 2026-10-05: `make try` runs on three small files in a temporary
     directory that it removes afterwards, also when a step fails,
     instead of on a fixed directory on one person's machine

attrsum.go

@@ -76,7 +76,8 @@ func (s *Stats) Print(opts *options, operation string) {
 		return
 	}
 
-	fmt.Fprintf(os.Stderr, "\n%s complete: %d files processed, %d skipped, %d failed, %s bytes in %s\n",
+	fmt.Fprintf(os.Stderr,
+		"\n%s complete: %d files processed, %d skipped, %d failed, %s bytes in %s\n",
 		operation,
 		s.FilesProcessed,
 		s.FilesSkipped,
@@ -171,11 +172,15 @@ func expandPaths(args []string) ([]string, error) {
 }
 
 // processFunc processes a single path within a command's run loop.
-type processFunc func(opts *options, path string, stats *Stats, bar *progressbar.ProgressBar) error
+type processFunc func(
+	opts *options, path string, stats *Stats, bar *progressbar.ProgressBar,
+) error
 
 // countAndBar counts the files under paths and returns a progress bar sized
 // to that total. It always returns either a non-nil bar or a non-nil error.
-func countAndBar(opts *options, paths []string, desc string) (*progressbar.ProgressBar, error) {
+func countAndBar(
+	opts *options, paths []string, desc string,
+) (*progressbar.ProgressBar, error) {
 	total, err := countFilesMultiple(opts, paths)
 	if err != nil {
 		return nil, err
@@ -193,7 +198,9 @@ func finishBar(bar *progressbar.ProgressBar) {
 
 // runOverPaths runs process over each path, sharing the progress/stats
 // bookkeeping common to the sum-add, sum-update and clear commands.
-func runOverPaths(opts *options, args []string, desc, op string, process processFunc) error {
+func runOverPaths(
+	opts *options, args []string, desc, op string, process processFunc,
+) error {
 	paths, err := expandPaths(args)
 	if err != nil {
 		return err
@@ -258,8 +265,11 @@ func newSumCmd(opts *options) *cobra.Command {
 	return cmd
 }
 
-func processSumAdd(opts *options, dir string, stats *Stats, bar *progressbar.ProgressBar) error {
-	return walkAndProcess(opts, dir, stats, bar, func(p string, info os.FileInfo, s *Stats) error {
+func processSumAdd(
+	opts *options, dir string, stats *Stats, bar *progressbar.ProgressBar,
+) error {
+	return walkAndProcess(opts, dir, stats, bar,
+		func(p string, info os.FileInfo, s *Stats) error {
 			if hasXattr(p, checksumKey) {
 				atomic.AddInt64(&s.FilesSkipped, 1)
 
@@ -277,8 +287,11 @@ func processSumAdd(opts *options, dir string, stats *Stats, bar *progressbar.Pro
 		})
 }
 
-func processSumUpdate(opts *options, dir string, stats *Stats, bar *progressbar.ProgressBar) error {
-	return walkAndProcess(opts, dir, stats, bar, func(p string, info os.FileInfo, s *Stats) error {
+func processSumUpdate(
+	opts *options, dir string, stats *Stats, bar *progressbar.ProgressBar,
+) error {
+	return walkAndProcess(opts, dir, stats, bar,
+		func(p string, info os.FileInfo, s *Stats) error {
 			t, err := readSumTime(p)
 			if err != nil || info.ModTime().After(t) {
 				werr := writeChecksumAndTime(opts, p, info, s)
@@ -297,7 +310,9 @@ func processSumUpdate(opts *options, dir string, stats *Stats, bar *progressbar.
 		})
 }
 
-func writeChecksumAndTime(opts *options, path string, info os.FileInfo, stats *Stats) error {
+func writeChecksumAndTime(
+	opts *options, path string, info os.FileInfo, stats *Stats,
+) error {
 	// Record mtime before hashing to detect modifications during hash.
 	mtimeBefore := info.ModTime()
 
@@ -368,8 +383,11 @@ func newClearCmd(opts *options) *cobra.Command {
 	}
 }
 
-func processClear(opts *options, dir string, stats *Stats, bar *progressbar.ProgressBar) error {
-	return walkAndProcess(opts, dir, stats, bar, func(p string, info os.FileInfo, s *Stats) error {
+func processClear(
+	opts *options, dir string, stats *Stats, bar *progressbar.ProgressBar,
+) error {
+	return walkAndProcess(opts, dir, stats, bar,
+		func(p string, info os.FileInfo, s *Stats) error {
 			cleared, err := clearOne(opts, p)
 			if err != nil {
 				atomic.AddInt64(&s.FilesFailed, 1)
@@ -433,7 +451,8 @@ func newCheckCmd(opts *options) *cobra.Command {
 			return runCheck(opts, a, cont)
 		},
 	}
-	cmd.Flags().BoolVar(&cont, "continue", false, "continue after errors and report each file")
+	cmd.Flags().BoolVar(&cont, "continue", false,
+		"continue after errors and report each file")
 
 	return cmd
 }
@@ -477,11 +496,14 @@ func runCheck(opts *options, args []string, cont bool) error {
 	return finalErr
 }
 
-func processCheck(opts *options, dir string, cont bool, stats *Stats, bar *progressbar.ProgressBar) error {
+func processCheck(
+	opts *options, dir string, cont bool, stats *Stats, bar *progressbar.ProgressBar,
+) error {
 	// Track initial failed count to detect failures during this walk.
 	initialFailed := atomic.LoadInt64(&stats.FilesFailed)
 
-	err := walkAndProcess(opts, dir, stats, bar, func(p string, _ os.FileInfo, s *Stats) error {
+	err := walkAndProcess(opts, dir, stats, bar,
+		func(p string, _ os.FileInfo, s *Stats) error {
 			return checkOne(opts, p, cont, s)
 		})
 	if err != nil {
@@ -747,7 +769,8 @@ func hasXattr(path, key string) bool {
 func fileMultihash(path string) ([]byte, int64, error) {
 	// The path is supplied by the operator as the tree to checksum; reading
 	// it is the entire purpose of the tool.
-	f, err := os.Open(path) //nolint:gosec // G304: operator-specified path is the intended input
+	//nolint:gosec // G304: operator-specified path is the intended input
+	f, err := os.Open(path)
 	if err != nil {
 		return nil, 0, err
 	}

script/bootstrap

@@ -9,9 +9,9 @@ set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 
-# Pinned versions, 2026-07-07 (same pins as the Dockerfile)
-# golangci-lint v2.10.1
-GOLANGCI_LINT_REF="github.com/golangci/golangci-lint/v2/cmd/golangci-lint@5d1e709b7be35cb2025444e19de266b056b7b7ee"
+# Pinned versions, 2026-10-05 (same pins as the Dockerfile)
+# golangci-lint v2.12.2
+GOLANGCI_LINT_REF="github.com/golangci/golangci-lint/v2/cmd/golangci-lint@c0d3ddc9cf3faa61a4e378e879ece580256d76e5"
 # goimports v0.42.0
 GOIMPORTS_REF="golang.org/x/tools/cmd/goimports@009367f5c17a8d4c45a961a3a509277190a9a6f0"