Never list index.mf at the top of the tree in gen and freshen (closes #233)

fetch saves the manifest as index.mf at the top of the tree and refuses a
manifest that lists a file there. gen given --output, and freshen with its
manifest outside the base directory, listed such a file, so they wrote
manifests fetch would not take.

Both now leave out each file the manifest would list as index.mf: one at
the top of the tree, or a file given to gen by that name. The rule goes by
that path alone and looks up no file, so a symlink named index.mf never
hides the file it points to. index.mf in a subdirectory is still listed.
The scanner in package mfer gets an option to leave out files by the path
they would be listed by.

Model: opus-5-5

README.md

@@ -304,9 +304,6 @@ are now tracked only in the [issues](https://git.eeqj.de/sneak/mfer/issues).
       `--no-extra-files` each one is a failure instead. A named pipe, socket or
       device, a symlink to a directory and a broken symlink are never reported,
       since gen cannot list them
-    - never reports `index.mf` at the top of the base directory as a file the
-      manifest does not list, even when given another manifest or a URL, since
-      gen and fetch write the manifest there
 - `mfer freshen` / `mfer freshen .`
     - rewrites `index.mf` to list the files now under the directory holding it,
       or under the one `--base` names, hashing only the files that are new or

internal/cli/check.go

@@ -195,10 +195,7 @@ func countCheckFailures(
 
 // findExtraFiles reports files present on disk but absent from the
 // manifest, and anything the search cannot read: each is a failure, logged
-// at error level, under --no-extra-files, otherwise a warning. index.mf at
-// the top of the base directory is never reported as absent from the
-// manifest, even when check is given another manifest or a URL, since gen
-// and fetch write the manifest there.
+// at error level, under --no-extra-files, otherwise a warning.
 func findExtraFiles(
 	ctx context.Context, cmd *cli.Command, chk *mfer.Checker, failures *int64,
 ) error {
@@ -207,10 +204,6 @@ func findExtraFiles(
 
 	go func() {
 		for result := range extraResults {
-			if result.Status == mfer.StatusExtra && result.Path == defaultManifestName {
-				continue
-			}
-
 			if cmd.Bool("no-extra-files") {
 				*failures++
 

internal/cli/entry_test.go

@@ -1191,99 +1191,6 @@ func TestCheckURLManifestWithoutTempDirectory(t *testing.T) {
 	assert.Equal(t, 0, runCLI(opts), "stderr: %s", testStderr(t, opts))
 }
 
-// TestCheckNeverReportsIndexMFAtTopOfBase checks a tree holding index.mf at
-// its top, where gen and fetch write the manifest, against a manifest that
-// does not list it, given by URL and by a path outside the tree: check never
-// reports it, and passes with and without --no-extra-files. index.mf in a
-// subdirectory, and the temp file fetch saves index.mf through, are still
-// reported.
-func TestCheckNeverReportsIndexMFAtTopOfBase(t *testing.T) {
-	t.Parallel()
-
-	files := map[string][]byte{testFileTxt: []byte("hello")}
-	manifest := manifestOf(t, files)
-
-	server := httptest.NewServer(fetchTestHandler(manifest, files))
-	t.Cleanup(server.Close)
-
-	manifestOutsideTree := filepath.Join(t.TempDir(), "other.mf")
-	require.NoError(t, os.WriteFile(manifestOutsideTree, manifest, 0o600))
-
-	for name, manifestArg := range map[string]string{
-		"manifest by URL":  server.URL + "/" + defaultManifestName,
-		"manifest by path": manifestOutsideTree,
-	} {
-		t.Run(name, func(t *testing.T) {
-			t.Parallel()
-
-			base := t.TempDir()
-			require.NoError(t, os.WriteFile(
-				filepath.Join(base, testFileTxt), files[testFileTxt], 0o600))
-			require.NoError(t, os.WriteFile(
-				filepath.Join(base, defaultManifestName), manifest, 0o600))
-
-			check := func(flags ...string) (int, string) {
-				opts := testOpts(slices.Concat(
-					[]string{testApp, cmdCheck}, flags,
-					[]string{testFlagBase, base, manifestArg},
-				), afero.NewOsFs())
-
-				return runCLI(opts), testStderr(t, opts)
-			}
-
-			exitCode, stderr := check()
-			assert.Equal(t, 0, exitCode, "stderr: %s", stderr)
-			assert.NotContains(t, stderr, "EXTRA: "+defaultManifestName)
-
-			exitCode, stderr = check(testFlagNoExtra)
-			assert.Equal(t, 0, exitCode, "stderr: %s", stderr)
-			assert.NotContains(t, stderr, "EXTRA: "+defaultManifestName)
-
-			reported := []string{
-				testSubdirManifest,
-				tempPathFor(defaultManifestName),
-			}
-
-			require.NoError(t, os.Mkdir(filepath.Join(base, testSubdir), 0o750))
-
-			for _, path := range reported {
-				require.NoError(t,
-					os.WriteFile(filepath.Join(base, path), manifest, 0o600))
-			}
-
-			exitCode, stderr = check(testFlagNoExtra)
-			assert.Equal(t, 1, exitCode, "stderr: %s", stderr)
-			assert.NotContains(t, stderr, "EXTRA: "+defaultManifestName)
-
-			for _, path := range reported {
-				assert.Contains(t, stderr, "EXTRA: "+path)
-			}
-		})
-	}
-}
-
-// TestCheckChecksListedIndexMF checks a tree against a manifest that lists
-// index.mf at the top of the tree, where that file has changed since: check
-// reports it like any other changed file.
-func TestCheckChecksListedIndexMF(t *testing.T) {
-	t.Parallel()
-
-	manifestPath := filepath.Join(t.TempDir(), "other.mf")
-	require.NoError(t, os.WriteFile(manifestPath, manifestOf(t, map[string][]byte{
-		defaultManifestName: []byte("listed"),
-	}), 0o600))
-
-	base := t.TempDir()
-	require.NoError(t, os.WriteFile(
-		filepath.Join(base, defaultManifestName), []byte("edited"), 0o600))
-
-	opts := testOpts([]string{
-		testApp, cmdCheck, testFlagBase, base, manifestPath,
-	}, afero.NewOsFs())
-	assert.Equal(t, 1, runCLI(opts), "stderr: %s", testStderr(t, opts))
-	assert.Contains(t, testStderr(t, opts), "HASH_MISMATCH: "+defaultManifestName)
-}
-
 // unlistableDirFs is a filesystem on which one directory cannot be listed.
 type unlistableDirFs struct {
 	afero.Fs
@@ -1332,60 +1239,6 @@ func TestCheckWithUnlistableDirectory(t *testing.T) {
 	assert.Contains(t, testStderr(t, opts), "unlisted.txt")
 }
 
-// TestCheckReportsUnreadableIndexMFAtTopOfBase has a directory named
-// index.mf at the top of the base that cannot be listed. check leaves out
-// only the report that index.mf is not in the manifest, so it reports the
-// error and fails under --no-extra-files.
-func TestCheckReportsUnreadableIndexMFAtTopOfBase(t *testing.T) {
-	t.Parallel()
-
-	unreadable := filepath.Join(testDir, defaultManifestName)
-
-	mem := afero.NewMemMapFs()
-	require.NoError(t, mem.MkdirAll(unreadable, 0o755))
-	writeTestFile(t, mem, testFile1, "hello")
-
-	opts := testOpts([]string{
-		testApp, cmdGenerate, "-q", "-o", testManifest, testDir,
-	}, mem)
-	require.Equal(t, 0, runCLI(opts), "stderr: %s", testStderr(t, opts))
-
-	fs := unlistableDirFs{Fs: mem, dir: unreadable}
-
-	opts = testOpts([]string{
-		testApp, cmdCheck, testFlagNoExtra, testFlagBase, testDir, testManifest,
-	}, fs)
-	assert.Equal(t, 1, runCLI(opts), "stderr: %s", testStderr(t, opts))
-	assert.Contains(t, testStderr(t, opts), "ERROR: "+defaultManifestName)
-}
-
-// TestCheckReportsUpperCaseIndexMFAtTopOfBase checks a tree holding
-// INDEX.MF at its top against a manifest that does not list it. Only the
-// name index.mf, in exactly that letter case, is left out, so check reports
-// INDEX.MF. The tree is in memory, where the two names are two files
-// whatever the letter case rules of the host's filesystem.
-func TestCheckReportsUpperCaseIndexMFAtTopOfBase(t *testing.T) {
-	t.Parallel()
-
-	upperCase := strings.ToUpper(defaultManifestName)
-
-	fs := afero.NewMemMapFs()
-	writeTestFile(t, fs, testFile1, "hello")
-
-	opts := testOpts([]string{
-		testApp, cmdGenerate, "-q", "-o", testManifest, testDir,
-	}, fs)
-	require.Equal(t, 0, runCLI(opts), "stderr: %s", testStderr(t, opts))
-
-	writeTestFile(t, fs, filepath.Join(testDir, upperCase), "not listed")
-
-	opts = testOpts([]string{
-		testApp, cmdCheck, testFlagNoExtra, testFlagBase, testDir, testManifest,
-	}, fs)
-	assert.Equal(t, 1, runCLI(opts), "stderr: %s", testStderr(t, opts))
-	assert.Contains(t, testStderr(t, opts), "EXTRA: "+upperCase)
-}
-
 func TestGenerateAtomicWriteNoTempFileOnSuccess(t *testing.T) {
 	t.Parallel()