Enforce real timeouts on gpg subprocess calls (closes #62)

Every gpg run now has a one-minute deadline (gpgTimeout) on top of its
caller's context and is killed when either ends. A timeout is reported
as "gpg timed out" under the failing operation instead of "signal:
killed". Only gpg itself is killed; WaitDelay (one second) stops the run
from waiting on a process gpg left behind that still holds its output,
such as a wrapper script that does not exec the real gpg.
Builder.Build and Checker.ExtractEmbeddedSigningKeyFP take a context, so
ToManifest's context now reaches signing and the contextcheck
suppression calling signing non-cancellable is gone. Manifest loading
takes no context, so its signature check is bounded by the timeout
alone.

Model: opus-5-5

README.md

@@ -23,8 +23,9 @@ javascript library is planned.
 
 # Build Status
 
-CI runs via `script/cibuild` (`docker build .`), which executes `make check`
+CI runs `script/cibuild`, which builds the Docker image with `--no-cache`, so
-(formatting, linting, tests). The `main` branch must always be green.
+the formatting, lint and test steps in the `Dockerfile` run on every build. The
+`main` branch must always be green.
 
 # Entrypoints
 
@@ -56,8 +57,8 @@ provide:
   Docker lint stage, whose image has no node
 - `script/check` — run `script/test`, `script/lint`, and `script/fmt-check`
 - `script/docker` — build the Docker image tagged with the project name
-- `script/cibuild` — CI entrypoint: `docker build .` (the Dockerfile runs the
+- `script/cibuild` — CI entrypoint: builds the image with the same command as
-  checks)
+  `script/docker`, uncached, so the checks in the Dockerfile run every time
 - `script/precommit` — pre-commit checks: `go mod tidy` verification, then
   `script/check`
 - `script/install-precommit` — install the git pre-commit hook that runs

TODO.md

@@ -28,6 +28,12 @@ only thing left of the `chore/align-repo-policies` branch is the list below.
   context ends, and a timeout reads as "gpg timed out" under the failing
   operation; `Builder.Build` and `Checker.ExtractEmbeddedSigningKeyFP` take a
   context, which reaches gpg (#62)
+- 2026-10-03: pinned the CLI error messages by driving the functions that emit
+  them in `internal/cli/errmsg_test.go`, and made the freshen mtime-presence
+  test distinguish an absent mtime from the epoch (#87)
+- 2026-10-03: `script/cibuild` builds the image with the same command as
+  `script/docker`, `--no-cache` included, so the checks in the Dockerfile run on
+  every build, also on an unchanged tree (#89)
 - 2026-10-03: `fetch` removes whatever sits at a file's temp name and then
   creates the temp file only if that name is free, so a hard link left there
   cannot make it write into a file outside the destination directory (#115)

internal/cli/errmsg_test.go

@@ -2,167 +2,354 @@
 package cli
 
 import (
-	"fmt"
+	"bytes"
+	"context"
+	"flag"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"os/exec"
+	"path/filepath"
 	"testing"
 
+	"github.com/spf13/afero"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	urfcli "github.com/urfave/cli/v2"
+	"sneak.berlin/go/mfer/mfer"
 )
 
-// errMsgCase is one pinned user-visible error message.
+// These tests pin the exact rendered text of the CLI's user-visible error
-type errMsgCase struct {
+// messages. The messages are grepped for in CI pipelines and quoted in bug
-	name string
+// reports, so a reword is a deliberate change, never a refactoring side
-	err  error
+// effect.
-	want string
+//
-}
+// Every case drives the real function that emits the message and asserts on
+// what it returns. No production format string is restated here: a test that
+// only re-rendered a copied format string would keep passing after the real
+// message changed, which is exactly the regression these tests exist to
+// catch.
 
+// Full 40-hex fingerprints used where a message embeds one.
 const (
 	msgFpA = "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
 	msgFpB = "BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB"
 )
 
-func checkErrMsgCases(t *testing.T, cases []errMsgCase) {
+// runLocked runs fn while holding runMu, so operations that write to the
+// process-global logger do not race the other CLI runs.
+func runLocked(fn func() error) error {
+	runMu.Lock()
+	defer runMu.Unlock()
+
+	return fn()
+}
+
+// unsignedChecker builds a Checker over a freshly scanned, unsigned manifest.
+func unsignedChecker(t *testing.T) *mfer.Checker {
 	t.Helper()
 
-	for _, tc := range cases {
+	fs := afero.NewMemMapFs()
-		t.Run(tc.name, func(t *testing.T) {
+	require.NoError(t, fs.MkdirAll("/d", 0o755))
-			t.Parallel()
+	require.NoError(t, afero.WriteFile(fs, "/d/f.txt", []byte("hi"), 0o644))
-			assert.Equal(t, tc.want, tc.err.Error())
+
-		})
+	s := mfer.NewScannerWithOptions(&mfer.ScannerOptions{Fs: fs})
-	}
+	require.NoError(t, s.EnumeratePath("/d", nil))
+
+	var buf bytes.Buffer
+
+	require.NoError(t, s.ToManifest(context.Background(), &buf, nil))
+	require.NoError(t, afero.WriteFile(fs, "/d/index.mf", buf.Bytes(), 0o644))
+
+	chk, err := mfer.NewChecker("/d/index.mf", "/d", fs)
+	require.NoError(t, err)
+	require.False(t, chk.IsSigned())
+
+	return chk
 }
 
-// TestErrorMessagesVerbatim pins the exact rendered text of the CLI's
+func TestNoManifestFoundMessage(t *testing.T) {
-// user-visible error messages.
+	t.Parallel()
+
+	_, err := findManifest(afero.NewMemMapFs(), "/tmp/x")
+	require.ErrorIs(t, err, errNoManifestFound)
+	assert.EqualError(t, err,
+		"no manifest found in /tmp/x (looked for index.mf and .index.mf)")
+}
+
+func TestVerifyRequiredSignerMessages(t *testing.T) {
+	t.Parallel()
+
+	t.Run("invalid fingerprint length", func(t *testing.T) {
+		t.Parallel()
+
+		err := verifyRequiredSigner(context.Background(),
+			unsignedChecker(t), "12345678")
+		require.ErrorIs(t, err, errInvalidFingerprint)
+		assert.EqualError(t, err,
+			"invalid fingerprint: must be exactly 40 hex characters, got 8")
+	})
+
+	t.Run("manifest not signed", func(t *testing.T) {
+		t.Parallel()
+
+		err := verifyRequiredSigner(context.Background(),
+			unsignedChecker(t), msgFpA)
+		require.ErrorIs(t, err, errManifestNotSigned)
+		assert.EqualError(t, err,
+			"manifest is not signed, but signature from "+msgFpA+" is required")
+	})
+}
+
+// TestSignerMismatchMessage drives verifyRequiredSigner against a real signed
+// manifest. The embedded fingerprint is whatever the generated key produced,
+// so it is read back from the checker and substituted into the expected
+// string; the required signer is a fixed value that cannot match it. Requires
+// gpg and is skipped where it is absent, as the other signing tests are.
 //
-// These strings are an interface: they are grepped for in CI pipelines
+//nolint:paralleltest // signedChecker calls t.Setenv, which bars t.Parallel
-// and quoted in bug reports. The messages are assembled by wrapping
+func TestSignerMismatchMessage(t *testing.T) {
-// static sentinels, and it is easy to change what a user sees while
+	chk := signedChecker(t)
-// only meaning to make an error matchable with errors.Is - which is
+
-// precisely what happened once already. Any change to a string below is
+	embeddedFP, err := chk.ExtractEmbeddedSigningKeyFP(context.Background())
-// therefore a deliberate, separately stated change, never a side effect
+	require.NoError(t, err)
-// of a refactor.
+
-func TestErrorMessagesVerbatim(t *testing.T) {
+	err = verifyRequiredSigner(context.Background(), chk, msgFpB)
+	require.ErrorIs(t, err, errSignerMismatch)
+	assert.EqualError(t, err,
+		"embedded signing key fingerprint "+embeddedFP+
+			" does not match required "+msgFpB)
+}
+
+// signedChecker builds a Checker over a manifest signed by a throwaway GPG
+// key generated in a temporary GNUPGHOME.
+func signedChecker(t *testing.T) *mfer.Checker {
+	t.Helper()
+
+	_, err := exec.LookPath("gpg")
+	if err != nil {
+		t.Skip("gpg not installed, skipping signing test")
+	}
+
+	gpgHome := t.TempDir()
+	params := "%no-protection\n" +
+		"Key-Type: RSA\nKey-Length: 2048\n" +
+		"Name-Real: MFER Test Key\nName-Email: test@mfer.test\n" +
+		"Expire-Date: 0\n%commit\n"
+	paramsFile := filepath.Join(gpgHome, "key-params")
+	require.NoError(t, os.WriteFile(paramsFile, []byte(params), 0o600))
+
+	//nolint:gosec // paramsFile is a test-controlled path inside t.TempDir()
+	cmd := exec.CommandContext(context.Background(), "gpg",
+		"--batch", "--gen-key", paramsFile)
+
+	cmd.Env = append(os.Environ(), "GNUPGHOME="+gpgHome)
+
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Skipf("failed to generate test GPG key: %v: %s", err, out)
+	}
+
+	t.Setenv("GNUPGHOME", gpgHome)
+
+	b := mfer.NewBuilder()
+	b.SetSigningOptions(&mfer.SigningOptions{KeyID: mfer.GPGKeyID("test@mfer.test")})
+
+	content := []byte("signed file")
+	_, err = b.AddFile("f.txt", mfer.FileSize(len(content)), mfer.ModTime{},
+		bytes.NewReader(content), nil)
+	require.NoError(t, err)
+
+	var buf bytes.Buffer
+
+	require.NoError(t, b.Build(context.Background(), &buf))
+
+	fs := afero.NewMemMapFs()
+	require.NoError(t, afero.WriteFile(fs, "/index.mf", buf.Bytes(), 0o644))
+
+	chk, err := mfer.NewChecker("/index.mf", "/", fs)
+	require.NoError(t, err)
+	require.True(t, chk.IsSigned())
+
+	return chk
+}
+
+func TestPathDoesNotExistMessage(t *testing.T) {
 	t.Parallel()
 
-	checkErrMsgCases(t, []errMsgCase{
+	set := flag.NewFlagSet("gen", flag.ContinueOnError)
-		{
+	require.NoError(t, set.Parse([]string{"nope"}))
-			name: "check: no manifest found",
+
-			err: fmt.Errorf("%w in %s (looked for index.mf and .index.mf)",
+	mfa := &CLIApp{Fs: afero.NewMemMapFs()}
-				errNoManifestFound, "/tmp/x"),
+	ctx := urfcli.NewContext(nil, set, nil)
-			want: "no manifest found in /tmp/x " +
+
-				"(looked for index.mf and .index.mf)",
+	_, err := mfa.collectInputPaths(ctx.Args())
-		},
+	require.ErrorIs(t, err, errPathNotExist)
-		{
+	assert.EqualError(t, err, "path does not exist: nope")
-			name: "check: invalid fingerprint length",
+}
-			err:  fmt.Errorf("%w, got %d", errInvalidFingerprint, 8),
+
-			want: "invalid fingerprint: must be exactly 40 hex characters, got 8",
+func TestOutputFileExistsMessage(t *testing.T) {
-		},
+	t.Parallel()
-		{
+
-			name: "check: manifest not signed",
+	fs := afero.NewMemMapFs()
-			err: fmt.Errorf("%w, but signature from %s is required",
+	require.NoError(t, fs.MkdirAll("/d", 0o755))
-				errManifestNotSigned, msgFpA),
+	require.NoError(t, afero.WriteFile(fs, "/d/f.txt", []byte("hi"), 0o644))
-			want: "manifest is not signed, but signature from " + msgFpA +
+	require.NoError(t, afero.WriteFile(fs, "/out.mf", []byte("old"), 0o644))
-				" is required",
+
-		},
+	set := flag.NewFlagSet("gen", flag.ContinueOnError)
-		{
+	set.String("output", "", "")
-			name: "check: signer mismatch",
+	set.Bool("force", false, "")
-			err: fmt.Errorf("embedded signing key fingerprint %s %w %s",
+	require.NoError(t, set.Parse([]string{"/d"}))
-				msgFpA, errSignerMismatch, msgFpB),
+	require.NoError(t, set.Set("output", "/out.mf"))
-			want: "embedded signing key fingerprint " + msgFpA +
+
-				" does not match required " + msgFpB,
+	mfa := &CLIApp{Fs: fs}
-		},
+	ctx := urfcli.NewContext(nil, set, nil)
-		{
+
-			name: "gen: path does not exist",
+	// generateManifestOperation writes to the process-global logger during
-			err:  fmt.Errorf("%w: %s", errPathNotExist, "nope"),
+	// enumeration, so serialize with the other CLI runs.
-			want: "path does not exist: nope",
+	err := runLocked(func() error { return mfa.generateManifestOperation(ctx) })
-		},
+	require.ErrorIs(t, err, errOutputExists)
-		{
+	assert.EqualError(t, err,
-			name: "gen: output file exists",
+		"output file /out.mf already exists (use --force to overwrite)")
-			err:  fmt.Errorf("output file %s %w", "index.mf", errOutputExists),
+}
-			want: "output file index.mf already exists " +
+
-				"(use --force to overwrite)",
+// TestUnknownCommandMessage drives the root command's action. run only logs
-		},
+// the error that action returns, so the test lets run build the app with no
-		{
+// command given and then runs that same app on an unknown command to get the
-			name: "mfer: unknown command",
+// error itself.
-			err:  fmt.Errorf("%w %q", errUnknownCommand, "bogus"),
+func TestUnknownCommandMessage(t *testing.T) {
-			want: `unknown command "bogus"`,
+	t.Parallel()
-		},
+
+	mfa := &CLIApp{
+		appname: testApp,
+		Stdout:  &bytes.Buffer{},
+		Stderr:  &bytes.Buffer{},
+		Fs:      afero.NewMemMapFs(),
+	}
+
+	// run points the process-global logger at this app's output, so
+	// serialize with the other CLI runs.
+	err := runLocked(func() error {
+		mfa.run([]string{testApp})
+
+		return mfa.app.Run([]string{testApp, "bogus"})
+	})
+	require.ErrorIs(t, err, errUnknownCommand)
+	assert.EqualError(t, err, `unknown command "bogus"`)
+}
+
+func TestManifestLoaderHTTPStatusMessage(t *testing.T) {
+	t.Parallel()
+
+	server := httptest.NewServer(
+		http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+			w.WriteHeader(http.StatusNotFound)
+		}))
+	defer server.Close()
+
+	mfa := &CLIApp{Fs: afero.NewMemMapFs()}
+
+	_, err := mfa.openManifestReader(server.URL + "/foo.mf")
+	require.ErrorIs(t, err, errHTTPStatus)
+	assert.EqualError(t, err,
+		"failed to fetch "+server.URL+"/foo.mf: HTTP 404")
+}
+
+func TestFetchManifestHTTPStatusMessage(t *testing.T) {
+	t.Parallel()
+
+	server := httptest.NewServer(
+		http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+			w.WriteHeader(http.StatusNotFound)
+		}))
+	defer server.Close()
+
+	set := flag.NewFlagSet("fetch", flag.ContinueOnError)
+	require.NoError(t, set.Parse([]string{server.URL}))
+
+	mfa := &CLIApp{Fs: afero.NewMemMapFs()}
+	ctx := urfcli.NewContext(nil, set, nil)
+
+	// fetchManifestOperation logs to the process-global logger.
+	err := runLocked(func() error { return mfa.fetchManifestOperation(ctx) })
+	require.ErrorIs(t, err, errHTTPStatus)
+	assert.EqualError(t, err, "failed to fetch manifest: HTTP 404")
+}
+
+func TestFetchFileHTTPStatusMessage(t *testing.T) {
+	t.Parallel()
+
+	server := httptest.NewServer(
+		http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+			w.WriteHeader(http.StatusInternalServerError)
+		}))
+	defer server.Close()
+
+	err := downloadFile(context.Background(), server.URL+"/x", "x",
+		&mfer.MFFilePath{}, nil)
+	require.ErrorIs(t, err, errHTTPStatus)
+	assert.EqualError(t, err, "HTTP 500")
+}
+
+func TestURLRequiredMessage(t *testing.T) {
+	t.Parallel()
+
+	set := flag.NewFlagSet("fetch", flag.ContinueOnError)
+	require.NoError(t, set.Parse([]string{}))
+
+	mfa := &CLIApp{Fs: afero.NewMemMapFs()}
+	ctx := urfcli.NewContext(nil, set, nil)
+
+	// fetchManifestOperation logs to the process-global logger.
+	err := runLocked(func() error { return mfa.fetchManifestOperation(ctx) })
+	require.ErrorIs(t, err, errURLRequired)
+	assert.EqualError(t, err, "URL argument required")
+}
+
+func TestSanitizePathMessages(t *testing.T) {
+	t.Parallel()
+
+	t.Run("empty", func(t *testing.T) {
+		t.Parallel()
+
+		_, err := sanitizePath("")
+		require.ErrorIs(t, err, errEmptyPath)
+		assert.EqualError(t, err, "empty path")
+	})
+
+	t.Run("absolute", func(t *testing.T) {
+		t.Parallel()
+
+		_, err := sanitizePath("/etc/passwd")
+		require.ErrorIs(t, err, errAbsolutePath)
+		assert.EqualError(t, err, "absolute path not allowed: /etc/passwd")
+	})
+
+	t.Run("traversal", func(t *testing.T) {
+		t.Parallel()
+
+		_, err := sanitizePath("../x")
+		require.ErrorIs(t, err, errPathTraversal)
+		assert.EqualError(t, err, "path traversal not allowed: ../x")
 	})
 }
 
-// TestFetchErrorMessagesVerbatim pins the fetch and manifest-loader
+func TestSizeMismatchMessage(t *testing.T) {
-// messages; see TestErrorMessagesVerbatim for why.
-func TestFetchErrorMessagesVerbatim(t *testing.T) {
 	t.Parallel()
 
-	checkErrMsgCases(t, []errMsgCase{
+	// finishDownload returns the size-mismatch error before it touches the
-		{
+	// paths, digest, or entry, so those can be zero here.
-			name: "manifest_loader: http status",
+	err := finishDownload("", "", 9, 10, nil, nil, nil, nil)
-			err: fmt.Errorf("failed to fetch %s: %w %d",
+	require.ErrorIs(t, err, errSizeMismatch)
-				"https://example.com/index.mf", errHTTPStatus, 404),
+	assert.EqualError(t, err, "size mismatch: expected 10 bytes, got 9")
-			want: "failed to fetch https://example.com/index.mf: HTTP 404",
-		},
-		{
-			name: "fetch: manifest http status",
-			err: fmt.Errorf("failed to fetch manifest: %w %d",
-				errHTTPStatus, 404),
-			want: "failed to fetch manifest: HTTP 404",
-		},
-		{
-			name: "fetch: file http status",
-			err:  fmt.Errorf("%w %d", errHTTPStatus, 500),
-			want: "HTTP 500",
-		},
-		{
-			name: "fetch: empty path",
-			err:  errEmptyPath,
-			want: "empty path",
-		},
-		{
-			name: "fetch: absolute path",
-			err:  fmt.Errorf("%w: %s", errAbsolutePath, "/etc/passwd"),
-			want: "absolute path not allowed: /etc/passwd",
-		},
-		{
-			name: "fetch: path traversal",
-			err:  fmt.Errorf("%w: %s", errPathTraversal, "../x"),
-			want: "path traversal not allowed: ../x",
-		},
-		{
-			name: "fetch: size mismatch",
-			err: fmt.Errorf("%w: expected %d bytes, got %d",
-				errSizeMismatch, 10, 9),
-			want: "size mismatch: expected 10 bytes, got 9",
-		},
-		{
-			name: "fetch: url required",
-			err:  errURLRequired,
-			want: "URL argument required",
-		},
-		{
-			name: "fetch: hash mismatch",
-			err:  errHashMismatch,
-			want: "hash mismatch",
-		},
-	})
 }
 
-// TestSentinelsAreMatchable checks that the wrapped forms of the
+func TestHashMismatchMessage(t *testing.T) {
-// messages above remain matchable with errors.Is, which is the reason
-// the sentinels exist at all.
-func TestSentinelsAreMatchable(t *testing.T) {
 	t.Parallel()
 
-	wrapped := fmt.Errorf("embedded signing key fingerprint %s %w %s",
+	// A 32-byte digest that matches none of the (empty) manifest hashes.
-		"a", errSignerMismatch, "b")
+	err := verifyDownloadedHash(make([]byte, 32), &mfer.MFFilePath{})
-	require.ErrorIs(t, wrapped, errSignerMismatch)
+	require.ErrorIs(t, err, errHashMismatch)
-
+	require.NotErrorIs(t, err, errSizeMismatch)
-	wrapped = fmt.Errorf("output file %s %w", "index.mf", errOutputExists)
+	assert.EqualError(t, err, "hash mismatch")
-	require.ErrorIs(t, wrapped, errOutputExists)
-
-	wrapped = fmt.Errorf("failed to fetch manifest: %w %d", errHTTPStatus, 404)
-	require.ErrorIs(t, wrapped, errHTTPStatus)
-
-	assert.NotErrorIs(t, errHashMismatch, errSizeMismatch)
 }

internal/cli/freshen_test.go

@@ -110,7 +110,10 @@ func TestFreshenRecordEntryMtimePresence(t *testing.T) {
 
 	const relPath = "file1.txt"
 
-	mtime := time.Unix(1_700_000_000, 0)
+	// The scanned file's mtime is the Unix epoch. If recordEntry ever misreads
+	// an absent manifest mtime as the epoch, the "absent" case below would
+	// compare equal to this and be classified unchanged, so the test fails.
+	mtime := time.Unix(0, 0)
 	info := stubFileInfo{size: 8, mtime: mtime}
 
 	for _, tc := range []struct {

mfer/gpg.go

@@ -19,6 +19,12 @@ const (
 	// time to type a passphrase or touch a smartcard.
 	gpgTimeout = time.Minute
 
+	// gpgWaitDelay is how long a gpg run keeps waiting for gpg's stdout
+	// and stderr to close once gpg has been killed or has exited. Reading
+	// what gpg itself wrote takes far less; only a process gpg left behind
+	// holds them open longer.
+	gpgWaitDelay = time.Second
+
 	// privateDirPerms is the permission mode for temporary GPG home
 	// directories.
 	privateDirPerms os.FileMode = 0o700
@@ -77,9 +83,12 @@ func gpgArgs(opts []string, positional ...string) []string {
 func runGPG(
 	ctx context.Context, stdin io.Reader, args ...string,
 ) (*bytes.Buffer, *bytes.Buffer, error) {
-	// exec.CommandContext kills only gpg itself, and that is enough: a
+	// exec.CommandContext kills only gpg itself. A gpg-agent that gpg
-	// gpg-agent that gpg starts runs detached in its own session and does
+	// starts runs detached and holds none of gpg's output, but another
-	// not hold gpg's output open, so Run returns as soon as gpg dies.
+	// process gpg leaves behind (a wrapper script that runs the real gpg
+	// without exec, for example) can keep gpg's stdout or stderr open, and
+	// Run would wait for it to exit. WaitDelay stops that wait
+	// gpgWaitDelay after the kill; that process is left running.
 	ctx, cancel := context.WithTimeout(ctx, gpgTimeout)
 	defer cancel()
 
@@ -92,6 +101,7 @@ func runGPG(
 	// and therefore cannot be reinterpreted by gpg as an option.
 	cmd := exec.CommandContext( //nolint:gosec // G204: see comment above
 		ctx, "gpg", fullArgs...)
+	cmd.WaitDelay = gpgWaitDelay
 	cmd.Stdin = stdin
 
 	var stdout, stderr bytes.Buffer

mfer/gpg_test.go

@@ -397,15 +397,24 @@ func TestBuilderWithoutSigning(t *testing.T) {
 		"signing public key should be empty when not signing")
 }
 
+// fakeGPGPath writes script as an executable named gpg into a temporary
+// directory and returns a PATH value with that directory first.
+func fakeGPGPath(t *testing.T, script string) string {
+	t.Helper()
+
+	binDir := t.TempDir()
+	//nolint:gosec // G306: the fake gpg has to be executable
+	require.NoError(t, os.WriteFile(filepath.Join(binDir, "gpg"),
+		[]byte(script), 0o700))
+
+	return binDir + string(os.PathListSeparator) + os.Getenv("PATH")
+}
+
 // TestGPGTimeoutKillsGPG puts a fake gpg that never finishes first on
 // PATH and checks that a run past its deadline is killed and reported as
 // a timeout of the named operation, instead of hanging.
 func TestGPGTimeoutKillsGPG(t *testing.T) {
-	binDir := t.TempDir()
+	t.Setenv("PATH", fakeGPGPath(t, "#!/bin/sh\nexec sleep 10\n"))
-	fakeGPG := []byte("#!/bin/sh\nexec sleep 10\n")
-	//nolint:gosec // G306: the fake gpg has to be executable
-	require.NoError(t, os.WriteFile(filepath.Join(binDir, "gpg"), fakeGPG, 0o700))
-	t.Setenv("PATH", binDir+string(os.PathListSeparator)+os.Getenv("PATH"))
 
 	ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
 	defer cancel()
@@ -415,6 +424,24 @@ func TestGPGTimeoutKillsGPG(t *testing.T) {
 	assert.Contains(t, err.Error(), "gpg sign failed: gpg timed out")
 }
 
+// TestGPGTimeoutWhenChildHoldsOutput uses a fake gpg that runs sleep as a
+// child instead of exec-ing it, the way a wrapper script around the real
+// gpg might. Killing the fake gpg leaves sleep holding its stdout and
+// stderr open; the call must still return shortly after the deadline
+// instead of waiting for sleep to exit.
+func TestGPGTimeoutWhenChildHoldsOutput(t *testing.T) {
+	t.Setenv("PATH", fakeGPGPath(t, "#!/bin/sh\nsleep 3\nexit\n"))
+
+	ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
+	defer cancel()
+
+	start := time.Now()
+	_, err := gpgSign(ctx, []byte("data"), GPGKeyID("any"))
+	require.ErrorIs(t, err, context.DeadlineExceeded)
+	assert.Less(t, time.Since(start), 3*time.Second,
+		"the call waited for the child holding gpg's output to exit")
+}
+
 // TestBuildPassesContextToSigning checks that a caller can cancel the gpg
 // runs that sign a manifest through the context given to Build.
 func TestBuildPassesContextToSigning(t *testing.T) {

script/cibuild

@@ -1,14 +1,24 @@
 #!/bin/sh
-# script/cibuild: run the CI build. The Dockerfile runs script/check
+# script/cibuild: run the CI build; the Gitea workflow runs this on push.
-# (via make check), so a successful build implies all checks pass.
+# It builds the image with the same command as script/docker. --no-cache
-# Generic: needs no adaptation. The Gitea workflow runs this on push.
+# because the checks the final stage depends on are RUN steps, and a
+# cached one is a check that did not run.
 set -eu
 
-ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
-    docker build .
+    # Own line: a failing command substitution inside an argument does
+    # not trip `set -e`, so the inline form degrades silently to an
+    # empty constant. The VERSION build argument takes precedence over
+    # the version a build stage derives from the .git in the context.
+    version="$(git describe --tags --always --dirty 2>/dev/null || true)"
+    [ -n "$version" ] || version="unknown"
+    docker build --no-cache \
+        --build-arg VERSION="$version" \
+        -t "$("$SCRIPT_DIR/projectname")" .
 }
 
 main "$@"