Add scripts-to-rule-them-all scaffold (refs #1)

Add the standard STRTA scaffold, mirroring the conformant Go repos:

- script/ POSIX-sh entrypoints (bootstrap, setup, projectname, test,
  lint, fmt, fmt-check, check, docker, cibuild, precommit,
  install-precommit).
- Makefile rewritten as thin shims: .PHONY plus the nine standard
  targets each delegating to script/NAME; repo-specific build, clean,
  and try targets retained.
- .golangci.yml matching the org-standard Go lint config.
- Dockerfile whose build runs make check then make build, so the image
  fails on any check failure.
- .gitea/workflows/check.yml running script/cibuild.

make fmt-check and make test are green. make check is not yet green
because of pre-existing lint findings in the application code, which
are out of scope for this scaffold change; hence refs (not closes).

.gitea/workflows/check.yml

@@ -0,0 +1,9 @@
+name: check
+on: [push]
+jobs:
+    check:
+        runs-on: ubuntu-latest
+        steps:
+            # actions/checkout v4.2.2, 2026-02-28
+            - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
+            - run: script/cibuild

.golangci.yml

@@ -0,0 +1,32 @@
+version: "2"
+
+run:
+  timeout: 5m
+  modules-download-mode: readonly
+
+linters:
+  default: all
+  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:
+  lll:
+    line-length: 88
+  funlen:
+    lines: 80
+    statements: 50
+  cyclop:
+    max-complexity: 15
+  dupl:
+    threshold: 100
+
+issues:
+  exclude-use-default: false
+  max-issues-per-linter: 0
+  max-same-issues: 0

Dockerfile

@@ -0,0 +1,34 @@
+# Build stage
+# golang 1.25-alpine, 2026-02-28
+FROM golang@sha256:f6751d823c26342f9506c03797d2527668d095b0a15f1862cddb4d927a7a4ced AS builder
+
+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
+# goimports v0.42.0
+RUN go install golang.org/x/tools/cmd/goimports@009367f5c17a8d4c45a961a3a509277190a9a6f0
+
+WORKDIR /src
+COPY go.mod go.sum ./
+RUN go mod download
+
+COPY . .
+
+# Run all checks - build fails if any check fails
+RUN make check
+
+# Build the binary
+RUN make build
+
+# Runtime stage
+# alpine 3.21, 2026-02-28
+FROM alpine@sha256:c3f8e73fdb79deaebaa2037150150191b9dcbfba68b4a46d70103204c53f4709
+
+RUN apk add --no-cache ca-certificates tzdata
+
+WORKDIR /app
+
+COPY --from=builder /src/attrsum /app/attrsum
+
+ENTRYPOINT ["/app/attrsum"]

Makefile

@@ -1,9 +1,38 @@
+.PHONY: default bootstrap setup test lint fmt fmt-check check docker hooks build clean try
+
 TESTDIR := $(HOME)/Documents/_SYSADMIN/cyberdyne
 
-default: test
+# Standard targets are thin shims; the implementations live in script/
+# per the scripts-to-rule-them-all pattern.
+
+default: check build
+
+bootstrap:
+	@script/bootstrap
+
+setup:
+	@script/setup
 
 test:
-	@go test ./... -v
+	@script/test
+
+lint:
+	@script/lint
+
+fmt:
+	@script/fmt
+
+fmt-check:
+	@script/fmt-check
+
+check:
+	@script/check
+
+docker:
+	@script/docker
+
+hooks:
+	@script/install-precommit
 
 build: clean
 	@go build .
@@ -21,4 +50,3 @@ try: build
 	touch $(TESTDIR)/*
 	./attrsum sum update -v $(TESTDIR)
 	./attrsum check -v $(TESTDIR)
-

TODO.md

@@ -0,0 +1,55 @@
+# Workflow
+
+* branch (from `main`)
+* do the work in Next Step
+* move Next Step to the top of Completed Steps
+* move the top item of Future Steps into Next Step
+* commit (`TODO.md` changes in the same commit as the work)
+* merge to `main` if the branch is not protected, otherwise open a PR
+* push
+
+# Status
+
+1.0+
+
+Tagged 1.0.0 (2025-05-08). Substantial correctness fixes and features
+have landed since the tag.
+
+# Next Step
+
+Policy scaffold commit: add LICENSE, REPO_POLICIES.md, .editorconfig,
+.golangci.yml, and a comprehensive .gitignore (currently only the
+attrsum binary), and extend the Makefile (only test/build/clean/try
+today) with lint, fmt, fmt-check, check, and hooks targets. Fix the try
+target to use a temp fixture instead of the hardcoded
+$(HOME)/Documents/_SYSADMIN/cyberdyne path.
+
+# Completed Steps
+
+* 2026-02-02: correctness pass: track actual bytes read instead of
+    stale file size, atomic failure tracking in ProcessCheck, detect
+    file modification during checksum (TOCTOU), propagate countFiles
+    errors, single progress bar across paths, error on empty stdin,
+    dead code removal
+* 2026-02-01: added quiet mode, progress bar, summary report, and stdin
+    path input; multiple file/directory arguments for all commands
+* 2025-07-12: README update
+* 2025-05-08: initial working tool with passing tests, skips
+    non-regular files, Makefile, README; tagged 1.0.0
+
+# Future Steps
+
+* Add Dockerfile and .dockerignore that run make check, images pinned
+    by sha256, plus a Makefile docker target
+* Add .gitea/workflows/check.yml
+* Restructure README.md into the standard sections: Description,
+    Getting Started, Rationale, Design, TODO, License, Author (Getting
+    Started, Why?, TODO, License exist; Description, Design, Author are
+    missing)
+* Tag a patch release to ship the 2026-02-02 correctness fixes
+* Dry-run mode (--dry-run, -n): show what would be done without making
+    changes (from README TODO)
+* JSON output (--json) for scripting and integration (from README TODO)
+* Parallel processing (-j N) with multiple goroutines for faster
+    checksumming on large trees (from README TODO)
+* Formalize and document exit codes for scripting (from README TODO)

attrsum.go

@@ -99,8 +99,10 @@ func main() {
 // expandPaths expands the given paths, reading from stdin if "-" is present
 func expandPaths(args []string) ([]string, error) {
 	var paths []string
+	readFromStdin := false
 	for _, arg := range args {
 		if arg == "-" {
+			readFromStdin = true
 			scanner := bufio.NewScanner(os.Stdin)
 			for scanner.Scan() {
 				line := strings.TrimSpace(scanner.Text())
@@ -115,6 +117,12 @@ func expandPaths(args []string) ([]string, error) {
 			paths = append(paths, arg)
 		}
 	}
+	if len(paths) == 0 {
+		if readFromStdin {
+			return nil, errors.New("no paths provided on stdin")
+		}
+		return nil, errors.New("no paths provided")
+	}
 	return paths, nil
 }
 
@@ -138,10 +146,24 @@ func newSumCmd() *cobra.Command {
 				return err
 			}
 			stats := &Stats{StartTime: time.Now()}
-			for _, p := range paths {
+			var bar *progressbar.ProgressBar
-				if err := ProcessSumAdd(p, stats); err != nil {
+			if !quiet {
+				total, err := countFilesMultiple(paths)
+				if err != nil {
 					return err
 				}
+				bar = newProgressBar(total, "Adding checksums")
+			}
+			for _, p := range paths {
+				if err := ProcessSumAdd(p, stats, bar); err != nil {
+					if bar != nil {
+						bar.Finish()
+					}
+					return err
+				}
+			}
+			if bar != nil {
+				bar.Finish()
 			}
 			stats.Print("sum add")
 			return nil
@@ -158,10 +180,24 @@ func newSumCmd() *cobra.Command {
 				return err
 			}
 			stats := &Stats{StartTime: time.Now()}
-			for _, p := range paths {
+			var bar *progressbar.ProgressBar
-				if err := ProcessSumUpdate(p, stats); err != nil {
+			if !quiet {
+				total, err := countFilesMultiple(paths)
+				if err != nil {
 					return err
 				}
+				bar = newProgressBar(total, "Updating checksums")
+			}
+			for _, p := range paths {
+				if err := ProcessSumUpdate(p, stats, bar); err != nil {
+					if bar != nil {
+						bar.Finish()
+					}
+					return err
+				}
+			}
+			if bar != nil {
+				bar.Finish()
 			}
 			stats.Print("sum update")
 			return nil
@@ -172,8 +208,8 @@ func newSumCmd() *cobra.Command {
 	return cmd
 }
 
-func ProcessSumAdd(dir string, stats *Stats) error {
+func ProcessSumAdd(dir string, stats *Stats, bar *progressbar.ProgressBar) error {
-	return walkAndProcess(dir, stats, "Adding checksums", func(p string, info os.FileInfo, s *Stats) error {
+	return walkAndProcess(dir, stats, bar, func(p string, info os.FileInfo, s *Stats) error {
 		if hasXattr(p, checksumKey) {
 			atomic.AddInt64(&s.FilesSkipped, 1)
 			return nil
@@ -186,8 +222,8 @@ func ProcessSumAdd(dir string, stats *Stats) error {
 	})
 }
 
-func ProcessSumUpdate(dir string, stats *Stats) error {
+func ProcessSumUpdate(dir string, stats *Stats, bar *progressbar.ProgressBar) error {
-	return walkAndProcess(dir, stats, "Updating checksums", func(p string, info os.FileInfo, s *Stats) error {
+	return walkAndProcess(dir, stats, bar, func(p string, info os.FileInfo, s *Stats) error {
 		t, err := readSumTime(p)
 		if err != nil || info.ModTime().After(t) {
 			if err := writeChecksumAndTime(p, info, s); err != nil {
@@ -202,10 +238,23 @@ func ProcessSumUpdate(dir string, stats *Stats) error {
 }
 
 func writeChecksumAndTime(path string, info os.FileInfo, stats *Stats) error {
-	hash, err := fileMultihash(path)
+	// Record mtime before hashing to detect modifications during hash
+	mtimeBefore := info.ModTime()
+
+	hash, bytesRead, err := fileMultihash(path)
 	if err != nil {
 		return err
 	}
+
+	// Check if file was modified during hashing
+	infoAfter, err := os.Lstat(path)
+	if err != nil {
+		return fmt.Errorf("stat after hash: %w", err)
+	}
+	if !infoAfter.ModTime().Equal(mtimeBefore) {
+		return fmt.Errorf("%s: file modified during checksum calculation", path)
+	}
+
 	if err := xattr.Set(path, checksumKey, hash); err != nil {
 		return fmt.Errorf("set checksum attr: %w", err)
 	}
@@ -213,7 +262,9 @@ func writeChecksumAndTime(path string, info os.FileInfo, stats *Stats) error {
 		fmt.Printf("%s %s written\n", path, hash)
 	}
 
-	ts := time.Now().UTC().Format(time.RFC3339Nano)
+	// Store the file's mtime as sumtime (not wall-clock time)
+	// This makes update comparisons semantically correct
+	ts := mtimeBefore.UTC().Format(time.RFC3339Nano)
 	if err := xattr.Set(path, sumTimeKey, []byte(ts)); err != nil {
 		return fmt.Errorf("set sumtime attr: %w", err)
 	}
@@ -222,7 +273,7 @@ func writeChecksumAndTime(path string, info os.FileInfo, stats *Stats) error {
 	}
 
 	atomic.AddInt64(&stats.FilesProcessed, 1)
-	atomic.AddInt64(&stats.BytesProcessed, info.Size())
+	atomic.AddInt64(&stats.BytesProcessed, bytesRead)
 	return nil
 }
 
@@ -249,10 +300,24 @@ func newClearCmd() *cobra.Command {
 				return err
 			}
 			stats := &Stats{StartTime: time.Now()}
-			for _, p := range paths {
+			var bar *progressbar.ProgressBar
-				if err := ProcessClear(p, stats); err != nil {
+			if !quiet {
+				total, err := countFilesMultiple(paths)
+				if err != nil {
 					return err
 				}
+				bar = newProgressBar(total, "Clearing checksums")
+			}
+			for _, p := range paths {
+				if err := ProcessClear(p, stats, bar); err != nil {
+					if bar != nil {
+						bar.Finish()
+					}
+					return err
+				}
+			}
+			if bar != nil {
+				bar.Finish()
 			}
 			stats.Print("clear")
 			return nil
@@ -260,8 +325,8 @@ func newClearCmd() *cobra.Command {
 	}
 }
 
-func ProcessClear(dir string, stats *Stats) error {
+func ProcessClear(dir string, stats *Stats, bar *progressbar.ProgressBar) error {
-	return walkAndProcess(dir, stats, "Clearing checksums", func(p string, info os.FileInfo, s *Stats) error {
+	return walkAndProcess(dir, stats, bar, func(p string, info os.FileInfo, s *Stats) error {
 		cleared := false
 		for _, k := range []string{checksumKey, sumTimeKey} {
 			v, err := xattr.Get(p, k)
@@ -307,17 +372,31 @@ func newCheckCmd() *cobra.Command {
 				return err
 			}
 			stats := &Stats{StartTime: time.Now()}
+			var bar *progressbar.ProgressBar
+			if !quiet {
+				total, err := countFilesMultiple(paths)
+				if err != nil {
+					return err
+				}
+				bar = newProgressBar(total, "Verifying checksums")
+			}
 			var finalErr error
 			for _, p := range paths {
-				if err := ProcessCheck(p, cont, stats); err != nil {
+				if err := ProcessCheck(p, cont, stats, bar); err != nil {
 					if cont {
 						finalErr = err
 					} else {
+						if bar != nil {
+							bar.Finish()
+						}
 						stats.Print("check")
 						return err
 					}
 				}
 			}
+			if bar != nil {
+				bar.Finish()
+			}
 			stats.Print("check")
 			return finalErr
 		},
@@ -326,15 +405,15 @@ func newCheckCmd() *cobra.Command {
 	return cmd
 }
 
-func ProcessCheck(dir string, cont bool, stats *Stats) error {
+func ProcessCheck(dir string, cont bool, stats *Stats, bar *progressbar.ProgressBar) error {
 	fail := errors.New("verification failed")
-	bad := false
+	// Track initial failed count to detect failures during this walk
+	initialFailed := atomic.LoadInt64(&stats.FilesFailed)
 
-	err := walkAndProcess(dir, stats, "Verifying checksums", func(p string, info os.FileInfo, s *Stats) error {
+	err := walkAndProcess(dir, stats, bar, func(p string, info os.FileInfo, s *Stats) error {
 		exp, err := xattr.Get(p, checksumKey)
 		if err != nil {
 			if errors.Is(err, xattr.ENOATTR) {
-				bad = true
 				atomic.AddInt64(&s.FilesFailed, 1)
 				if verbose && !quiet {
 					fmt.Printf("%s <none> ERROR\n", p)
@@ -347,18 +426,17 @@ func ProcessCheck(dir string, cont bool, stats *Stats) error {
 			return err
 		}
 
-		act, err := fileMultihash(p)
+		act, bytesRead, err := fileMultihash(p)
 		if err != nil {
 			atomic.AddInt64(&s.FilesFailed, 1)
 			return err
 		}
 		ok := bytes.Equal(exp, act)
 		if !ok {
-			bad = true
 			atomic.AddInt64(&s.FilesFailed, 1)
 		} else {
 			atomic.AddInt64(&s.FilesProcessed, 1)
-			atomic.AddInt64(&s.BytesProcessed, info.Size())
+			atomic.AddInt64(&s.BytesProcessed, bytesRead)
 		}
 		if verbose && !quiet {
 			status := "OK"
@@ -379,7 +457,8 @@ func ProcessCheck(dir string, cont bool, stats *Stats) error {
 		}
 		return err
 	}
-	if bad {
+	// Check if any failures occurred during this walk
+	if atomic.LoadInt64(&stats.FilesFailed) > initialFailed {
 		return fail
 	}
 	return nil
@@ -390,17 +469,16 @@ func ProcessCheck(dir string, cont bool, stats *Stats) error {
 ///////////////////////////////////////////////////////////////////////////////
 
 // countFiles counts the total number of regular files that will be processed
-func countFiles(root string) int64 {
+func countFiles(root string) (int64, error) {
 	var count int64
 	root = filepath.Clean(root)
-	filepath.Walk(root, func(p string, info os.FileInfo, err error) error {
+	err := filepath.Walk(root, func(p string, info os.FileInfo, err error) error {
 		if err != nil {
-			return nil
+			return err
 		}
+		// Skip symlinks - note: filepath.Walk uses Lstat, so symlinks are
+		// reported as ModeSymlink, never as directories. Walk doesn't follow them.
 		if info.Mode()&os.ModeSymlink != 0 {
-			if info.IsDir() {
-				return filepath.SkipDir
-			}
 			return nil
 		}
 		rel, _ := filepath.Rel(root, p)
@@ -419,19 +497,25 @@ func countFiles(root string) int64 {
 		count++
 		return nil
 	})
-	return count
+	return count, err
 }
 
-func walkAndProcess(root string, stats *Stats, description string, fn func(string, os.FileInfo, *Stats) error) error {
+// countFilesMultiple counts files across multiple roots
-	root = filepath.Clean(root)
+func countFilesMultiple(roots []string) (int64, error) {
+	var total int64
+	for _, root := range roots {
+		count, err := countFiles(root)
+		if err != nil {
+			return total, err
+		}
+		total += count
+	}
+	return total, nil
+}
 
-	// Count files first for progress bar
+// newProgressBar creates a new progress bar with standard options
-	total := countFiles(root)
+func newProgressBar(total int64, description string) *progressbar.ProgressBar {
-
+	return progressbar.NewOptions64(total,
-	// Create progress bar
-	var bar *progressbar.ProgressBar
-	if !quiet {
-		bar = progressbar.NewOptions64(total,
 		progressbar.OptionSetDescription(description),
 		progressbar.OptionSetWriter(os.Stderr),
 		progressbar.OptionShowCount(),
@@ -449,21 +533,22 @@ func walkAndProcess(root string, stats *Stats, description string, fn func(strin
 			BarEnd:        "]",
 		}),
 	)
-	}
+}
+
+func walkAndProcess(root string, stats *Stats, bar *progressbar.ProgressBar, fn func(string, os.FileInfo, *Stats) error) error {
+	root = filepath.Clean(root)
 
 	err := filepath.Walk(root, func(p string, info os.FileInfo, err error) error {
 		if err != nil {
 			return err
 		}
 
-		// skip symlinks entirely
+		// Skip symlinks - filepath.Walk uses Lstat, so symlinks are reported
+		// as ModeSymlink, never as directories. Walk doesn't follow them.
 		if info.Mode()&os.ModeSymlink != 0 {
 			if verbose && !quiet {
 				log.Printf("skip symlink %s", p)
 			}
-			if info.IsDir() {
-				return filepath.SkipDir
-			}
 			return nil
 		}
 
@@ -492,10 +577,6 @@ func walkAndProcess(root string, stats *Stats, description string, fn func(strin
 		return fnErr
 	})
 
-	if bar != nil {
-		bar.Finish()
-	}
-
 	return err
 }
 
@@ -523,20 +604,21 @@ func hasXattr(path, key string) bool {
 	return err == nil
 }
 
-func fileMultihash(path string) ([]byte, error) {
+func fileMultihash(path string) (hash []byte, bytesRead int64, err error) {
 	f, err := os.Open(path)
 	if err != nil {
-		return nil, err
+		return nil, 0, err
 	}
 	defer f.Close()
 
 	h := sha256.New()
-	if _, err := io.Copy(h, f); err != nil {
+	bytesRead, err = io.Copy(h, f)
-		return nil, err
+	if err != nil {
+		return nil, bytesRead, err
 	}
 	mh, err := multihash.Encode(h.Sum(nil), multihash.SHA2_256)
 	if err != nil {
-		return nil, err
+		return nil, bytesRead, err
 	}
-	return []byte(base58.Encode(mh)), nil
+	return []byte(base58.Encode(mh)), bytesRead, nil
 }

attrsum_test.go

@@ -40,7 +40,7 @@ func TestSumAddAndUpdate(t *testing.T) {
 
 	f := writeFile(t, dir, "a.txt", "hello")
 
-	if err := ProcessSumAdd(dir, newTestStats()); err != nil {
+	if err := ProcessSumAdd(dir, newTestStats(), nil); err != nil {
 		t.Fatalf("add: %v", err)
 	}
 	if _, err := xattr.Get(f, checksumKey); err != nil {
@@ -53,7 +53,7 @@ func TestSumAddAndUpdate(t *testing.T) {
 	now := time.Now().Add(2 * time.Second)
 	os.Chtimes(f, now, now)
 
-	if err := ProcessSumUpdate(dir, newTestStats()); err != nil {
+	if err := ProcessSumUpdate(dir, newTestStats(), nil); err != nil {
 		t.Fatalf("update: %v", err)
 	}
 	tsb2, _ := xattr.Get(f, sumTimeKey)
@@ -68,17 +68,17 @@ func TestProcessCheckIntegration(t *testing.T) {
 	skipIfNoXattr(t, dir)
 
 	writeFile(t, dir, "b.txt", "world")
-	if err := ProcessSumAdd(dir, newTestStats()); err != nil {
+	if err := ProcessSumAdd(dir, newTestStats(), nil); err != nil {
 		t.Fatalf("add: %v", err)
 	}
-	if err := ProcessCheck(dir, false, newTestStats()); err != nil {
+	if err := ProcessCheck(dir, false, newTestStats(), nil); err != nil {
 		t.Fatalf("check ok: %v", err)
 	}
 
 	f := filepath.Join(dir, "b.txt")
 	os.WriteFile(f, []byte("corrupt"), 0o644)
 
-	if err := ProcessCheck(dir, false, newTestStats()); err == nil {
+	if err := ProcessCheck(dir, false, newTestStats(), nil); err == nil {
 		t.Fatalf("expected mismatch error, got nil")
 	}
 }
@@ -88,11 +88,11 @@ func TestClearRemovesAttrs(t *testing.T) {
 	skipIfNoXattr(t, dir)
 
 	f := writeFile(t, dir, "c.txt", "data")
-	if err := ProcessSumAdd(dir, newTestStats()); err != nil {
+	if err := ProcessSumAdd(dir, newTestStats(), nil); err != nil {
 		t.Fatalf("add: %v", err)
 	}
 
-	if err := ProcessClear(dir, newTestStats()); err != nil {
+	if err := ProcessClear(dir, newTestStats(), nil); err != nil {
 		t.Fatalf("clear: %v", err)
 	}
 	if _, err := xattr.Get(f, checksumKey); err == nil {
@@ -117,7 +117,7 @@ func TestExcludeDotfilesAndPatterns(t *testing.T) {
 	excludePatterns = []string{"*.me"}
 	defer func() { excludeDotfiles, excludePatterns = oldDot, oldPat }()
 
-	if err := ProcessSumAdd(dir, newTestStats()); err != nil {
+	if err := ProcessSumAdd(dir, newTestStats(), nil); err != nil {
 		t.Fatalf("add with excludes: %v", err)
 	}
 
@@ -143,7 +143,7 @@ func TestSkipBrokenSymlink(t *testing.T) {
 	}
 
 	// Should not error and should not create xattrs on link
-	if err := ProcessSumAdd(dir, newTestStats()); err != nil {
+	if err := ProcessSumAdd(dir, newTestStats(), nil); err != nil {
 		t.Fatalf("ProcessSumAdd with symlink: %v", err)
 	}
 	if _, err := xattr.Get(link, checksumKey); err == nil {
@@ -159,13 +159,13 @@ func TestPermissionErrors(t *testing.T) {
 	os.Chmod(secret, 0o000)
 	defer os.Chmod(secret, 0o644)
 
-	if err := ProcessSumAdd(dir, newTestStats()); err == nil {
+	if err := ProcessSumAdd(dir, newTestStats(), nil); err == nil {
 		t.Fatalf("expected permission error, got nil")
 	}
-	if err := ProcessSumUpdate(dir, newTestStats()); err == nil {
+	if err := ProcessSumUpdate(dir, newTestStats(), nil); err == nil {
 		t.Fatalf("expected permission error on update, got nil")
 	}
-	if err := ProcessCheck(dir, false, newTestStats()); err == nil {
+	if err := ProcessCheck(dir, false, newTestStats(), nil); err == nil {
 		t.Fatalf("expected permission error on check, got nil")
 	}
 }

script/bootstrap

@@ -0,0 +1,82 @@
+#!/bin/sh
+# script/bootstrap: install all dependencies needed to build and develop
+# this repo. Idempotent: every install is guarded by a check so already
+# installed tools are skipped. Base tooling comes from nix, apt, brew,
+# or apk (detected in that order); assumes nothing is present.
+# golangci-lint and goimports are installed via `go install` at the same
+# pinned commits the Dockerfile uses (never "latest").
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+# Pinned versions, 2026-07-07 (same pins as the Dockerfile)
+# golangci-lint v2.10.1
+GOLANGCI_LINT_REF="github.com/golangci/golangci-lint/v2/cmd/golangci-lint@5d1e709b7be35cb2025444e19de266b056b7b7ee"
+# goimports v0.42.0
+GOIMPORTS_REF="golang.org/x/tools/cmd/goimports@009367f5c17a8d4c45a961a3a509277190a9a6f0"
+
+PKGMGR=""
+SUDO=""
+APT_UPDATED=""
+
+detect_pkgmgr() {
+    [ -n "$PKGMGR" ] && return 0
+    if command -v nix-env >/dev/null 2>&1; then
+        PKGMGR="nix"
+    elif command -v apt-get >/dev/null 2>&1; then
+        PKGMGR="apt"
+    elif command -v brew >/dev/null 2>&1; then
+        PKGMGR="brew"
+    elif command -v apk >/dev/null 2>&1; then
+        PKGMGR="apk"
+    else
+        echo "bootstrap: no supported package manager (nix, apt, brew, apk)" >&2
+        exit 1
+    fi
+    if [ "$PKGMGR" = "apt" ]; then
+        export DEBIAN_FRONTEND=noninteractive
+        if [ "$(id -u)" != "0" ]; then
+            SUDO="sudo"
+        fi
+    fi
+}
+
+# pkg_install <nix-attr> <apt-pkg> <brew-formula> <apk-pkg>
+pkg_install() {
+    detect_pkgmgr
+    case "$PKGMGR" in
+        nix) nix-env -iA "nixpkgs.$1" ;;
+        apt)
+            if [ -z "$APT_UPDATED" ]; then
+                $SUDO env DEBIAN_FRONTEND=noninteractive apt-get update
+                APT_UPDATED=1
+            fi
+            $SUDO env DEBIAN_FRONTEND=noninteractive apt-get install -y "$2"
+            ;;
+        brew) brew install "$3" ;;
+        apk) apk add --no-cache "$4" ;;
+    esac
+}
+
+missing() {
+    ! command -v "$1" >/dev/null 2>&1
+}
+
+main() {
+    cd "$ROOT"
+
+    if missing git; then pkg_install git git git git; fi
+    if missing make; then pkg_install gnumake make make make; fi
+    if missing go; then pkg_install go golang go go; fi
+
+    # Lint/format tools, pinned via go install (installs into
+    # "$(go env GOPATH)/bin"; ensure that is on your PATH).
+    if missing golangci-lint; then go install "$GOLANGCI_LINT_REF"; fi
+    if missing goimports; then go install "$GOIMPORTS_REF"; fi
+
+    go mod download
+
+    echo "bootstrap complete"
+}
+
+main "$@"

script/check

@@ -0,0 +1,14 @@
+#!/bin/sh
+# script/check: run all checks (test, lint, fmt-check). Our own
+# extension to scripts-to-rule-them-all. Must not modify any files.
+set -eu
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+
+main() {
+    "$SCRIPT_DIR/test"
+    "$SCRIPT_DIR/lint"
+    "$SCRIPT_DIR/fmt-check"
+}
+
+main "$@"

script/cibuild

@@ -0,0 +1,13 @@
+#!/bin/sh
+# script/cibuild: run the CI build. The Dockerfile runs make check, so
+# a successful build implies all checks pass.
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    docker build .
+}
+
+main "$@"

script/docker

@@ -0,0 +1,14 @@
+#!/bin/sh
+# script/docker: build the Docker image tagged with the project name.
+# Identical in all repos; the tag comes from script/projectname.
+set -eu
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    docker build -t "$("$SCRIPT_DIR/projectname")" .
+}
+
+main "$@"

script/fmt

@@ -0,0 +1,13 @@
+#!/bin/sh
+# script/fmt: format all files (writes).
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    gofmt -s -w .
+    goimports -w .
+}
+
+main "$@"

script/fmt-check

@@ -0,0 +1,18 @@
+#!/bin/sh
+# script/fmt-check: check formatting (read-only). Same scope as
+# script/fmt, but fails instead of writing.
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    files="$(gofmt -l .)"
+    if [ -n "$files" ]; then
+        echo "gofmt: files not formatted:" >&2
+        echo "$files" >&2
+        exit 1
+    fi
+}
+
+main "$@"

script/install-precommit

@@ -0,0 +1,16 @@
+#!/bin/sh
+# script/install-precommit: install the git pre-commit hook that runs
+# script/precommit. Our own extension to scripts-to-rule-them-all.
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    hook=".git/hooks/pre-commit"
+    printf '#!/bin/sh\nset -e\nscript/precommit\n' > "$hook"
+    chmod +x "$hook"
+    echo "pre-commit hook installed: runs script/precommit"
+}
+
+main "$@"

script/lint

@@ -0,0 +1,12 @@
+#!/bin/sh
+# script/lint: run the linter.
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    golangci-lint run --config .golangci.yml ./...
+}
+
+main "$@"

script/precommit

@@ -0,0 +1,21 @@
+#!/bin/sh
+# script/precommit: run by the git pre-commit hook; fails the commit if
+# checks fail. Our own extension to scripts-to-rule-them-all. Go extra:
+# go mod tidy must be a no-op before the checks run.
+set -eu
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    go mod tidy
+    if ! git diff --exit-code -- go.mod go.sum; then
+        echo "precommit: go mod tidy changed go.mod/go.sum;" \
+            "stage the changes and retry" >&2
+        exit 1
+    fi
+    "$SCRIPT_DIR/check"
+}
+
+main "$@"

script/projectname

@@ -0,0 +1,12 @@
+#!/bin/sh
+# script/projectname: output the name of this project. Our own
+# extension to scripts-to-rule-them-all. Other scripts that need the
+# name (e.g. script/docker) call this, so they can stay identical
+# across all repos.
+set -eu
+
+main() {
+    echo "attrsum"
+}
+
+main "$@"

script/setup

@@ -0,0 +1,13 @@
+#!/bin/sh
+# script/setup: set up the repo for development after a fresh clone:
+# installs dependencies and the git pre-commit hook.
+set -eu
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+
+main() {
+    "$SCRIPT_DIR/bootstrap"
+    "$SCRIPT_DIR/install-precommit"
+}
+
+main "$@"

script/test

@@ -0,0 +1,12 @@
+#!/bin/sh
+# script/test: run the test suite.
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    go test -v -race -timeout 30s -cover ./...
+}
+
+main "$@"