List a file given to Scanner.EnumeratePath by its name (closes #182)

EnumeratePath treated its argument as a directory: given a file, it
listed it under an empty path and ToManifest stopped with "path cannot
be empty". It now hands its one path to EnumeratePaths, which lists a
directory's files by their paths under it and a file by its name, as
EnumerateFile does. EnumeratePath's own resolution of a directory named
through a symlink goes with it, since EnumeratePaths does the same.

Model: opus-5-5

mfer/scanner.go

@@ -139,33 +139,15 @@ func (s *Scanner) EnumerateFile(filePath string) error {
 	return s.enumerateFileWithInfo(filepath.Base(abs), basePath, info, nil)
 }
 
-// EnumeratePath walks a directory path and adds all files to the scanner.
+// EnumeratePath adds inputPath, a directory or a file, to the scanner as
+// EnumeratePaths adds each of its paths.
 // If progress is non-nil, status updates are sent as files are discovered.
 // The progress channel is closed when the method returns.
 func (s *Scanner) EnumeratePath(
 	inputPath string,
 	progress chan<- EnumerateStatus,
 ) error {
-	if progress != nil {
+	return s.EnumeratePaths(progress, inputPath)
-		defer close(progress)
-	}
-
-	abs, err := filepath.Abs(inputPath)
-	if err != nil {
-		return err
-	}
-
-	// The walk does not follow a symlink at its top, so a directory named
-	// through one is resolved first. If that fails, the directory is walked
-	// as named and the walk reports the problem.
-	resolved, err := filepath.EvalSymlinks(abs)
-	if err == nil {
-		abs = resolved
-	}
-
-	afs := afero.NewReadOnlyFs(afero.NewBasePathFs(s.fs, abs))
-
-	return s.enumerateFS(afs, abs, progress)
 }
 
 // EnumeratePaths adds to the scanner the files under each directory path,

mfer/scanner_test.go

@@ -118,6 +118,27 @@ func TestScannerEnumeratePathWithProgress(t *testing.T) {
 	assert.Equal(t, FileSize(6), final.BytesFound)
 }
 
+// TestScannerEnumeratePathFile gives EnumeratePath a file: it is listed
+// by its name, as EnumerateFile lists it, and the manifest can be built.
+func TestScannerEnumeratePathFile(t *testing.T) {
+	t.Parallel()
+
+	fs := afero.NewMemMapFs()
+	require.NoError(t, fs.MkdirAll("/dir", 0o755))
+	require.NoError(t, afero.WriteFile(fs, "/dir/one.txt", []byte("1"), 0o644))
+
+	s := NewScannerWithOptions(&ScannerOptions{Fs: fs})
+	require.NoError(t, s.EnumeratePath("/dir/one.txt", nil))
+
+	var buf bytes.Buffer
+	require.NoError(t, s.ToManifest(context.Background(), &buf, nil))
+
+	m, err := NewManifestFromReader(&buf)
+	require.NoError(t, err)
+	require.Len(t, m.Files(), 1)
+	assert.Equal(t, "one.txt", m.Files()[0].GetPath())
+}
+
 func TestScannerEnumeratePaths(t *testing.T) {
 	t.Parallel()