Limit report and trees to given paths (closes #174) (#191)

internal/sfdupes/cli.go

@@ -49,6 +49,13 @@ const escapesHelp = `Four characters in a path are escaped, so each row stays on
   \r  a carriage return
 `
 
+// operandsHelp is the paragraph of the report and trees help on their
+// PATH operands (README "Operands of `report` and `trees`").
+const operandsHelp = `With PATH operands, only the records at or below them are used. A
+relative PATH is joined to the working directory. No PATH is looked up
+on the filesystem, so a symlink in one is not followed.
+`
+
 // reportHelp, treesHelp, infoHelp and dwimHelp follow the one-line
 // summary in the help of their subcommands.
 const (
@@ -61,7 +68,7 @@ row per duplicate file. The columns are:
 
 Rows are ordered by size, largest first, then by path.
 
-` + escapesHelp
+` + escapesHelp + "\n" + operandsHelp
 
 	treesHelp = `The report is tab-separated text on stdout: a header line, then one
 row per duplicate directory tree. The columns are:
@@ -74,7 +81,7 @@ row per duplicate directory tree. The columns are:
 
 Rows are ordered by size, largest first, then by path.
 
-` + escapesHelp
+` + escapesHelp + "\n" + operandsHelp
 
 	infoHelp = `The details go to stdout, one per line. Each line holds a name and its
 value, separated by a tab:
@@ -108,6 +115,11 @@ var errWorkersBelowOne = errors.New("--workers must be at least 1")
 // would name the working directory.
 var errEmptyExcludeValue = errors.New("--exclude must not be empty")
 
+// errEmptyOperand is the usage error for an empty PATH operand of
+// report or trees, as from "$DIR" with DIR unset. Taken as a path, it
+// would name the working directory.
+var errEmptyOperand = errors.New("PATH must not be empty")
+
 // Version is the build version, injected at link time via -ldflags
 // (see the Makefile); empty when the linker set none, as for a binary
 // built by go install. buildVersion turns it into what --version prints.
@@ -229,20 +241,20 @@ func newRootCommand(stdout, stderr io.Writer) *cobra.Command {
 		"print the version to stdout")
 
 	reportCmd := &cobra.Command{
-		Use:   cmdReport,
+		Use:   cmdReport + " [PATH...]",
 		Short: "Read the scan database and print the file-level duplicates report",
-		Args:  cobra.NoArgs,
-		RunE: runE(func(ctx context.Context, _ []string) error {
-			return runReport(ctx, stdout)
+		Args:  rejectEmptyOperand,
+		RunE: runE(func(ctx context.Context, args []string) error {
+			return runReport(ctx, args, stdout)
 		}),
 	}
 
 	treesCmd := &cobra.Command{
-		Use:   cmdTrees,
+		Use:   cmdTrees + " [PATH...]",
 		Short: "Read the scan database and print the duplicate-tree report",
-		Args:  cobra.NoArgs,
-		RunE: runE(func(ctx context.Context, _ []string) error {
-			return runTrees(ctx, stdout)
+		Args:  rejectEmptyOperand,
+		RunE: runE(func(ctx context.Context, args []string) error {
+			return runTrees(ctx, args, stdout)
 		}),
 	}
 
@@ -387,6 +399,18 @@ func rejectEmptyExcludeValue(cmd *cobra.Command, excludePaths []string) error {
 	return errEmptyExcludeValue
 }
 
+// rejectEmptyOperand rejects an empty PATH operand of report or trees.
+// That is a usage error reported in one line, as for --workers below 1.
+func rejectEmptyOperand(cmd *cobra.Command, args []string) error {
+	if !slices.Contains(args, "") {
+		return nil
+	}
+
+	cmd.SilenceUsage = true
+
+	return errEmptyOperand
+}
+
 // runE adapts a subcommand implementation, or the version print, to
 // cobra's RunE. Cobra prints the error and the command's usage text for
 // every error RunE returns, but a subcommand that ran and failed has no

internal/sfdupes/cli_test.go

@@ -583,14 +583,14 @@ func TestRunNamesDefaultDatabase(t *testing.T) {
 		},
 		cmdReport: {
 			run: func() error {
-				return runReport(cancelledContext(t), io.Discard)
+				return runReport(cancelledContext(t), nil, io.Discard)
 			},
 			want: "report: database " + defaultDatabasePath + " (default)\n" +
 				reportOpenLine + "\n" + reportOpenLine + "\n",
 		},
 		cmdTrees: {
 			run: func() error {
-				return runTrees(cancelledContext(t), io.Discard)
+				return runTrees(cancelledContext(t), nil, io.Discard)
 			},
 			want: "trees: database " + defaultDatabasePath + " (default)\n" +
 				treesOpenLine + "\n" + treesOpenLine + "\n",
@@ -626,8 +626,6 @@ func TestRunUsageErrors(t *testing.T) {
 	}{
 		"no subcommand":      {[]string{}, usageMarker},
 		"scan without paths": {[]string{cmdScan}, usageMarker},
-		"report with args":   {[]string{cmdReport, "x"}, usageMarker},
-		"trees with args":    {[]string{cmdTrees, "x"}, usageMarker},
 		"info with args":     {[]string{cmdInfo, "x"}, usageMarker},
 		"dwim with args":     {[]string{cmdDwim, "x"}, usageMarker},
 		"unknown flag":       {[]string{cmdScan, "--nope", "/"}, usageMarker},
@@ -764,11 +762,16 @@ func TestRunHelpDescribesDatabaseAndOutput(t *testing.T) {
 	t.Parallel()
 
 	// README §Settings: the help names the database, and says what
-	// report, trees, info and dwim print.
+	// report, trees, info and dwim print. The help of report and trees
+	// also explains their PATH operands.
 	database := []string{
 		"scan and dwim store", databaseEnv, defaultDatabasePath, "needs root",
 	}
 	escapes := []string{`\\`, `\t`, `\n`, `\r`}
+	operands := []string{
+		"With PATH operands", "at or below them", "working directory",
+		"No PATH is looked up", "not followed",
+	}
 
 	// The subcommand whose help is printed; none for the root.
 	cases := []struct {
@@ -779,17 +782,17 @@ func TestRunHelpDescribesDatabaseAndOutput(t *testing.T) {
 		{[]string{cmdScan}, database},
 		{
 			[]string{cmdReport},
-			append([]string{
+			slices.Concat([]string{
 				"tab-separated", "\n  first ", "\n  dupe ", "\n  size ",
 				"largest first",
-			}, escapes...),
+			}, escapes, operands),
 		},
 		{
 			[]string{cmdTrees},
-			append([]string{
+			slices.Concat([]string{
 				"tab-separated", "\n  first ", "\n  dupe ", "\n  files ",
 				"\n  size ", "\n  disk_size ", "largest first",
-			}, escapes...),
+			}, escapes, operands),
 		},
 		{
 			[]string{cmdInfo},
@@ -1839,9 +1842,13 @@ func TestStdoutWriteErrorPropagates(t *testing.T) {
 	scanFixture(t)
 
 	cases := map[string]func(context.Context, io.Writer) error{
-		cmdReport: runReport,
-		cmdTrees:  runTrees,
-		cmdInfo:   runInfo,
+		cmdReport: func(ctx context.Context, w io.Writer) error {
+			return runReport(ctx, nil, w)
+		},
+		cmdTrees: func(ctx context.Context, w io.Writer) error {
+			return runTrees(ctx, nil, w)
+		},
+		cmdInfo: runInfo,
 	}
 
 	for name, fn := range cases {

internal/sfdupes/dwim.go

@@ -26,7 +26,7 @@ func runDwim(
 		return err
 	}
 
-	err = runTrees(ctx, stdout)
+	err = runTrees(ctx, nil, stdout)
 	if err != nil {
 		return err
 	}

internal/sfdupes/report.go

@@ -9,6 +9,7 @@ import (
 	"io"
 	"io/fs"
 	"os"
+	"path/filepath"
 	"slices"
 	"strings"
 	"syscall"
@@ -44,10 +45,12 @@ func reportPhase(name string) string {
 }
 
 // runReport implements the report subcommand: it prints the file-level
-// duplicates report as TSV on stdout. Of the scanned filesystem it
-// only checks, with pathExists, that each path in a duplicate group is
-// still there. It names the database on stderr before it opens it. Any
-// database problem, including a missing database, is fatal.
+// duplicates report as TSV on stdout, from the records at or below the
+// operands in args, or from every record when args is empty. Of the
+// scanned filesystem it only checks, with pathExists, that each path in
+// a duplicate group is still there; it never looks up an operand. It
+// names the database on stderr before it opens it. Any database
+// problem, including a missing database, is fatal.
 //
 // The work runs in two phases, each under a progress display of its
 // own on stderr: open (open the database) and read (read the number of
@@ -55,7 +58,12 @@ func reportPhase(name string) string {
 // order, writing each size's duplicate groups to stdout once that size
 // is read; see readReport). Each display ends before the next phase
 // starts, and before an error is returned to be printed.
-func runReport(ctx context.Context, stdout io.Writer) error {
+func runReport(ctx context.Context, args []string, stdout io.Writer) error {
+	operands, err := cleanOperands(args)
+	if err != nil {
+		return err
+	}
+
 	dbPath, source, err := databasePath()
 	if err != nil {
 		return err
@@ -87,7 +95,8 @@ func runReport(ctx context.Context, stdout io.Writer) error {
 		label: reportPhase("read"), unit: "records", total: -1,
 		waitingFor: countingRecords, stalledOn: "db/disk/out",
 	})
-	report, err := readReport(ctx, db, dbPath, stdout, pathExists, prog)
+	report, err := readReport(ctx, db, dbPath, operands, stdout, pathExists,
+		prog)
 
 	prog.finish()
 
@@ -108,12 +117,14 @@ func runReport(ctx context.Context, stdout io.Writer) error {
 // dbPath, as its total, then reads every record in signature order,
 // counting each on prog, and writes the report to stdout: the header
 // line, then the rows of each size's duplicate groups once that size is
-// read. A path for which exists returns false is left out of its group.
-// stdout may be the terminal prog is drawn on, so the lines go through
-// prog's writer. It returns what it wrote, with the totals for the
-// summary line.
+// read. Only the records that underOperand finds under operands join a
+// group, and a path for which exists returns false is left out of its
+// group. stdout may be the terminal prog is drawn on, so the lines go
+// through prog's writer. It returns what it wrote, with the totals for
+// the summary line.
 func readReport(ctx context.Context, db *sql.DB, dbPath string,
-	stdout io.Writer, exists func(path string) bool, prog *progress,
+	operands []string, stdout io.Writer, exists func(path string) bool,
+	prog *progress,
 ) (*reportWriter, error) {
 	out := prog.writer(stdout)
 	report := &reportWriter{out: out, exists: exists}
@@ -128,6 +139,12 @@ func readReport(ctx context.Context, db *sql.DB, dbPath string,
 	err = loadSignatureRows(ctx, db, prog.setTotal, func(r scanRec) error {
 		prog.increment()
 
+		report.records++
+
+		if !underOperand(r.path, operands) {
+			return nil
+		}
+
 		writeErr = report.add(r)
 
 		return writeErr
@@ -159,7 +176,7 @@ func readReport(ctx context.Context, db *sql.DB, dbPath string,
 // records of one size, so it holds only the duplicate groups of the
 // size being read, and writes them, ordered by first path, once a
 // record of a smaller size comes. It counts what the summary line
-// reports.
+// reports; readReport counts the records read.
 type reportWriter struct {
 	out io.Writer
 
@@ -179,8 +196,6 @@ type reportWriter struct {
 // its paths; any other ends them, and one of a smaller size first
 // writes the groups of the size before.
 func (w *reportWriter) add(r scanRec) error {
-	w.records++
-
 	if r.size == w.sig.size && r.head == w.sig.head &&
 		r.tail == w.sig.tail && r.content == w.sig.content {
 		w.paths = append(w.paths, r.path)
@@ -273,6 +288,47 @@ func pathExists(path string) bool {
 	return !errors.Is(err, fs.ErrNotExist) && !errors.Is(err, syscall.ENOTDIR)
 }
 
+// cleanOperands returns the operands of report or trees, each made
+// absolute by absolutePath and then cleaned. The records hold real
+// paths, with no "." or ".." element and no repeated or trailing
+// slash, so an operand is cleaned to match them. No operand is looked
+// up on the filesystem. None is empty: rejectEmptyOperand refuses an
+// empty operand on the command line.
+func cleanOperands(args []string) ([]string, error) {
+	operands := make([]string, 0, len(args))
+
+	for _, a := range args {
+		abs, err := absolutePath(a)
+		if err != nil {
+			return nil, fmt.Errorf("resolve path %s: %w", escapePath(a), err)
+		}
+
+		operands = append(operands, filepath.Clean(abs))
+	}
+
+	return operands, nil
+}
+
+// underOperand reports whether path is one of operands or lies below
+// one of them. Each operand is clean and absolute, as cleanOperands
+// returns it. With no operands, a report covers the whole database, so
+// underOperand is true for every path.
+func underOperand(path string, operands []string) bool {
+	if len(operands) == 0 {
+		return true
+	}
+
+	for _, o := range operands {
+		// Only the root directory's clean path ends in "/".
+		dir := strings.TrimSuffix(o, "/") + "/"
+		if path == o || strings.HasPrefix(path, dir) {
+			return true
+		}
+	}
+
+	return false
+}
+
 // escapePath returns a path as it is written in a report column (README
 // "Report output format"): a backslash, tab, newline or carriage return
 // becomes \\, \t, \n or \r, and every other byte is kept as it is.

internal/sfdupes/report_test.go

@@ -102,7 +102,8 @@ func dupeGroups(t *testing.T, db *sql.DB) []dupeGroup {
 
 	var out bytes.Buffer
 
-	_, err := readReport(t.Context(), db, "", &out, everyPathExists, nil)
+	_, err := readReport(t.Context(), db, "", nil, &out, everyPathExists,
+		nil)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -148,6 +149,136 @@ func dupeGroupsOf(t *testing.T, recs []scanRec) []dupeGroup {
 	return dupeGroups(t, db)
 }
 
+// TestRunReportOperands runs report with operands on three copies of
+// one file, two of them under srv/photos, and a fourth copy in
+// srv/photos2, all in a new directory. Only the records at or below the
+// operands form the groups and the totals, however each operand is
+// written.
+//
+//nolint:paralleltest // captureStderr replaces the process-wide os.Stderr
+func TestRunReportOperands(t *testing.T) {
+	h := testHash("h")
+
+	recs := make([]scanRec, 0, 4)
+	for _, p := range []string{
+		"/a/copy", "/srv/photos/x", "/srv/photos/y", "/srv/photos2/z",
+	} {
+		recs = append(recs,
+			scanRec{size: 7, head: h, tail: h, content: h, path: p})
+	}
+
+	dir, recs := recsOnDisk(t, recs)
+	a, x, y, z := recs[0].path, recs[1].path, recs[2].path, recs[3].path
+
+	t.Setenv(databaseEnv, seedDatabase(t, recs))
+
+	header := "first\tdupe\tsize\n"
+	row := func(first, dupe string) string {
+		return first + "\t" + dupe + "\t7\n"
+	}
+	photos := header + row(x, y)
+
+	cases := map[string]struct {
+		operands []string
+		want     string
+		summary  string
+	}{
+		"directory": {[]string{dir + "/srv/photos"}, photos,
+			"1 duplicate groups, 1 dupe files, 7 B reclaimable"},
+		"trailing slash":  {[]string{dir + "/srv/photos/"}, photos, ""},
+		"dot and dot-dot": {[]string{dir + "/srv/./a/../photos"}, photos, ""},
+		"files":           {[]string{a, z}, header + row(a, z), ""},
+		"overlapping": {[]string{dir + "/srv", dir + "/srv/photos"},
+			header + row(x, y) + row(x, z), ""},
+		"root": {[]string{"/"},
+			header + row(a, x) + row(a, y) + row(a, z), ""},
+		"no record": {[]string{dir + "/srv/photo"}, header,
+			"0 duplicate groups, 0 dupe files, 0 B reclaimable"},
+	}
+
+	for name, tc := range cases {
+		t.Run(name, func(t *testing.T) {
+			var stdout bytes.Buffer
+
+			stderr := captureStderr(t)
+
+			code := run(append([]string{cmdReport}, tc.operands...),
+				&stdout, os.Stderr)
+			if code != exitOK {
+				t.Fatalf("run(report %q) = %d, want %d; stderr: %s",
+					tc.operands, code, exitOK, stderr())
+			}
+
+			if got := stdout.String(); got != tc.want {
+				t.Errorf("stdout = %q, want %q", got, tc.want)
+			}
+
+			// The records read are all four, whatever the operands.
+			summary := "report: 4 records read, " + tc.summary + "\n"
+			if got := stderr(); tc.summary != "" &&
+				!strings.HasSuffix(got, summary) {
+				t.Errorf("stderr = %q, want it to end %q", got, summary)
+			}
+		})
+	}
+}
+
+//nolint:paralleltest // t.Chdir changes the process-wide working directory
+func TestCleanOperandsMakesRelativePathsAbsolute(t *testing.T) {
+	dir := t.TempDir()
+	t.Chdir(dir)
+
+	wd, err := absolutePath(".")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	got, err := cleanOperands([]string{"photos/", "a/../b", "/c//d"})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	want := []string{
+		filepath.Join(wd, "photos"), filepath.Join(wd, "b"), "/c/d",
+	}
+	if !slices.Equal(got, want) {
+		t.Errorf("cleanOperands = %q, want %q", got, want)
+	}
+}
+
+// TestRunReportsRejectEmptyOperand checks that an empty PATH operand of
+// report or trees, alone or after another operand, is a usage error
+// reported in one line before the database is opened (README "Error
+// handling and exit codes").
+func TestRunReportsRejectEmptyOperand(t *testing.T) {
+	cases := map[string][]string{
+		"report":           {cmdReport, ""},
+		"trees":            {cmdTrees, ""},
+		"after an operand": {cmdTrees, t.TempDir(), ""},
+	}
+
+	for name, args := range cases {
+		t.Run(name, func(t *testing.T) {
+			// No database exists there, so opening one would be a fatal
+			// error, exit 1.
+			t.Setenv(databaseEnv, testDBPath(t))
+
+			var stdout, stderr bytes.Buffer
+
+			code := run(args, &stdout, &stderr)
+			if code != exitUsage {
+				t.Errorf("run(%q) = %d, want %d", args, code, exitUsage)
+			}
+
+			want := "Error: PATH must not be empty\n"
+			if stdout.String() != "" || stderr.String() != want {
+				t.Errorf("stdout, stderr = %q, %q, want \"\", %q",
+					stdout.String(), stderr.String(), want)
+			}
+		})
+	}
+}
+
 func TestRunReportEscapesPaths(t *testing.T) {
 	dir, recs := recsOnDisk(t, awkwardPairRecs())
 	t.Setenv(databaseEnv, seedDatabase(t, recs))
@@ -195,7 +326,7 @@ func TestReportStdoutFailsWhileReading(t *testing.T) {
 	// Counts the records read, and draws nothing.
 	prog := &progress{now: time.Now}
 
-	_, err = readReport(t.Context(), db, "", failingWriter{},
+	_, err = readReport(t.Context(), db, "", nil, failingWriter{},
 		everyPathExists, prog)
 	if !errors.Is(err, errWriteFailed) ||
 		!strings.HasPrefix(err.Error(), "write stdout: ") {
@@ -292,7 +423,8 @@ func TestReadReportOnTerminal(t *testing.T) {
 		waitingFor: countingRecords,
 	}, terminalWidth, time.Hour, time.Now)
 
-	_, err = readReport(t.Context(), db, "", os.Stderr, everyPathExists, p)
+	_, err = readReport(t.Context(), db, "", nil, os.Stderr,
+		everyPathExists, p)
 
 	p.finish()
 
@@ -514,7 +646,7 @@ func TestReadReportChecksOnlyPossibleDuplicates(t *testing.T) {
 		return true
 	}
 
-	_, err = readReport(t.Context(), db, "", io.Discard, exists, nil)
+	_, err = readReport(t.Context(), db, "", nil, io.Discard, exists, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -548,7 +680,8 @@ func TestReadReportDropsGroupLeftWithOnePath(t *testing.T) {
 
 	exists := func(path string) bool { return path != "/a/gone" }
 
-	report, err := readReport(t.Context(), db, "", io.Discard, exists, nil)
+	report, err := readReport(t.Context(), db, "", nil, io.Discard, exists,
+		nil)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -581,7 +714,7 @@ func TestReadReportKeepsGroupLeftWithTwoPaths(t *testing.T) {
 
 	var out bytes.Buffer
 
-	report, err := readReport(t.Context(), db, "", &out, exists, nil)
+	report, err := readReport(t.Context(), db, "", nil, &out, exists, nil)
 	if err != nil {
 		t.Fatal(err)
 	}

internal/sfdupes/trees.go

@@ -37,12 +37,14 @@ func treesPhase(name string) string {
 
 // runTrees implements the trees subcommand: it reads every record from
 // the database in path order, reconstructs the directory hierarchy from
-// the record paths, computes a Merkle-style digest per directory, and
-// prints maximal duplicate-tree groups as TSV on stdout. Of the scanned
-// filesystem it only checks, with pathExists, that the root of each
-// duplicate tree is still there, never the files below it. It names the
-// database on stderr before it opens it. Any database problem,
-// including a missing database, is fatal.
+// the paths of the records at or below the operands in args (of every
+// record when args is empty), computes a Merkle-style digest per
+// directory, and prints maximal duplicate-tree groups as TSV on stdout.
+// Of the scanned filesystem it only checks, with pathExists, that the
+// root of each duplicate tree is still there, never the files below it;
+// it never looks up an operand. It names the database on stderr before
+// it opens it. Any database problem, including a missing database, is
+// fatal.
 //
 // The work runs in four phases, each under a progress display of its
 // own on stderr: open (open the database), read (read the number of
@@ -50,7 +52,12 @@ func treesPhase(name string) string {
 // hierarchy), group (group the directories by digest) and write (write
 // the groups to stdout). Each display ends before the next phase
 // starts, and before an error is returned to be printed.
-func runTrees(ctx context.Context, stdout io.Writer) error {
+func runTrees(ctx context.Context, args []string, stdout io.Writer) error {
+	operands, err := cleanOperands(args)
+	if err != nil {
+		return err
+	}
+
 	dbPath, source, err := databasePath()
 	if err != nil {
 		return err
@@ -79,7 +86,7 @@ func runTrees(ctx context.Context, stdout io.Writer) error {
 		label: treesPhase("read"), unit: "records", total: -1,
 		waitingFor: countingRecords, stalledOn: "db",
 	})
-	records, super, allDirs, err := readTree(ctx, db, prog)
+	records, super, allDirs, err := readTree(ctx, db, operands, prog)
 
 	prog.finish()
 
@@ -118,10 +125,17 @@ func runTrees(ctx context.Context, stdout io.Writer) error {
 }
 
 // readTree gives prog the number of records in db as its total, then
-// reads every record in path order into the directory hierarchy,
-// counting each on prog. It returns the number of records read, the
-// super-root and every directory.
-func readTree(ctx context.Context, db *sql.DB,
+// reads every record in path order, counting each on prog. It adds the
+// records that underOperand finds under operands to the directory
+// hierarchy. It returns the number of records read, the super-root and
+// every directory at or below one of operands.
+//
+// Any other directory lies above an operand and can hold files that are
+// not used, so its digest does not describe it. It is left out of the
+// directories returned. A directory whose parent is left out gets the
+// super-root as its parent, so suppressed never judges its group by
+// that parent's digest.
+func readTree(ctx context.Context, db *sql.DB, operands []string,
 	prog *progress,
 ) (int, *treeNode, []*treeNode, error) {
 	records := 0
@@ -131,7 +145,10 @@ func readTree(ctx context.Context, db *sql.DB,
 		records++
 
 		prog.increment()
-		tree.add(r)
+
+		if underOperand(r.path, operands) {
+			tree.add(r)
+		}
 	})
 	if err != nil {
 		return 0, nil, nil, err
@@ -139,7 +156,21 @@ func readTree(ctx context.Context, db *sql.DB,
 
 	super, allDirs := tree.finish()
 
-	return records, super, allDirs, nil
+	dirs := allDirs[:0]
+
+	for _, d := range allDirs {
+		if !underOperand(d.path, operands) {
+			continue
+		}
+
+		if !underOperand(d.parent.path, operands) {
+			d.parent = super
+		}
+
+		dirs = append(dirs, d)
+	}
+
+	return records, super, dirs, nil
 }
 
 // writeTreeGroups writes dupes to stdout as TSV, a header line and then

internal/sfdupes/trees_test.go

@@ -214,6 +214,57 @@ func TestRunTreesEscapesPaths(t *testing.T) {
 	}
 }
 
+// TestRunTreesOperands runs trees with operands on records in a new
+// directory. x/a and y/a are copies, and so are y/a and srv/b. x and y
+// also hold files that differ. Given x/a and y/a, trees reads x and y
+// as holding one copy each of a, yet neither is reported: only the
+// directories at or below an operand are.
+func TestRunTreesOperands(t *testing.T) {
+	f, g, k := testHash("f"), testHash("g"), testHash("k")
+	dir, recs := recsOnDisk(t, []scanRec{
+		{size: 10, head: f, tail: f, content: f, path: "/srv/b/f"},
+		{size: 10, head: f, tail: f, content: f, path: "/x/a/f"},
+		{size: 20, head: g, tail: g, content: g, path: "/x/g"},
+		{size: 10, head: f, tail: f, content: f, path: "/y/a/f"},
+		{size: 30, head: k, tail: k, content: k, path: "/y/k"},
+	})
+	b, xa, ya := dir+"/srv/b", dir+"/x/a", dir+"/y/a"
+
+	header := "first\tdupe\tfiles\tsize\tdisk_size\n"
+	row := func(first, dupe string) string {
+		return first + "\t" + dupe + "\t1\t10\t0\n"
+	}
+
+	cases := map[string]struct {
+		operands []string
+		want     string
+	}{
+		"none":       {nil, header + row(b, xa) + row(b, ya)},
+		"two copies": {[]string{xa, ya}, header + row(xa, ya)},
+		"parents":    {[]string{dir + "/x", dir + "/y"}, header + row(xa, ya)},
+		"one copy":   {[]string{b}, header},
+	}
+
+	for name, tc := range cases {
+		t.Run(name, func(t *testing.T) {
+			t.Setenv(databaseEnv, seedDatabase(t, recs))
+
+			var stdout, stderr bytes.Buffer
+
+			code := run(append([]string{cmdTrees}, tc.operands...),
+				&stdout, &stderr)
+			if code != exitOK {
+				t.Fatalf("run(trees %q) = %d, want %d; stderr: %s",
+					tc.operands, code, exitOK, stderr.String())
+			}
+
+			if got := stdout.String(); got != tc.want {
+				t.Errorf("stdout = %q, want %q", got, tc.want)
+			}
+		})
+	}
+}
+
 // TestRunTreesDiskSize runs trees on two copies of a tree whose files
 // take different space on disk. The row's disk_size is the sum over the
 // dupe copy's files, those in its subdirectory included.