common: parser error fix resulting in deadlock

common/git_utils.go

@@ -396,12 +396,17 @@ func (e *GitHandlerImpl) GitExecQuietOrPanic(cwd string, params ...string) {
 }
 
 type ChanIO struct {
-	ch chan byte
+	ch   chan byte
+	done chan struct{}
 }
 
 func (c *ChanIO) Write(p []byte) (int, error) {
 	for _, b := range p {
-		c.ch <- b
+		select {
+		case c.ch <- b:
+		case <-c.done:
+			return 0, io.EOF
+		}
 	}
 	return len(p), nil
 }
@@ -410,21 +415,32 @@ func (c *ChanIO) Write(p []byte) (int, error) {
 func (c *ChanIO) Read(data []byte) (idx int, err error) {
 	var ok bool
 
-	data[idx], ok = <-c.ch
-	if !ok {
-		err = io.EOF
-		return
-	}
-	idx++
-
-	for len(c.ch) > 0 && idx < len(data) {
-		data[idx], ok = <-c.ch
+	select {
+	case data[idx], ok = <-c.ch:
 		if !ok {
 			err = io.EOF
 			return
 		}
-
 		idx++
+	case <-c.done:
+		err = io.EOF
+		return
+	}
+
+	for len(c.ch) > 0 && idx < len(data) {
+		select {
+		case data[idx], ok = <-c.ch:
+			if !ok {
+				err = io.EOF
+				return
+			}
+			idx++
+		case <-c.done:
+			err = io.EOF
+			return
+		default:
+			return
+		}
 	}
 
 	return
@@ -471,7 +487,14 @@ func parseGitMsg(data <-chan byte) (GitMsg, error) {
 	var size int
 
 	pos := 0
-	for c := <-data; c != ' '; c = <-data {
+	for {
+		c, ok := <-data
+		if !ok {
+			return GitMsg{}, io.EOF
+		}
+		if c == ' ' {
+			break
+		}
 		if (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') {
 			id[pos] = c
 			pos++
@@ -483,7 +506,15 @@ func parseGitMsg(data <-chan byte) (GitMsg, error) {
 
 	pos = 0
 	var c byte
-	for c = <-data; c != ' ' && c != '\x00'; c = <-data {
+	for {
+		var ok bool
+		c, ok = <-data
+		if !ok {
+			return GitMsg{}, io.EOF
+		}
+		if c == ' ' || c == '\x00' {
+			break
+		}
 		if c >= 'a' && c <= 'z' {
 			msgType[pos] = c
 			pos++
@@ -509,7 +540,14 @@ func parseGitMsg(data <-chan byte) (GitMsg, error) {
 		return GitMsg{}, fmt.Errorf("Invalid object type: '%s'", string(msgType))
 	}
 
-	for c = <-data; c != '\000'; c = <-data {
+	for {
+		c, ok := <-data
+		if !ok {
+			return GitMsg{}, io.EOF
+		}
+		if c == '\x00' {
+			break
+		}
 		if c >= '0' && c <= '9' {
 			size = size*10 + (int(c) - '0')
 		} else {
@@ -528,18 +566,37 @@ func parseGitCommitHdr(oldHdr [2]string, data <-chan byte) ([2]string, int, erro
 	hdr := make([]byte, 0, 60)
 	val := make([]byte, 0, 1000)
 
-	c := <-data
+	c, ok := <-data
+	if !ok {
+		return [2]string{}, 0, io.EOF
+	}
 	size := 1
 	if c != '\n' { // end of header marker
-		for ; c != ' '; c = <-data {
+		for {
+			if c == ' ' {
+				break
+			}
 			hdr = append(hdr, c)
 			size++
+			var ok bool
+			c, ok = <-data
+			if !ok {
+				return [2]string{}, size, io.EOF
+			}
 		}
 		if size == 1 { // continuation header here
 			hdr = []byte(oldHdr[0])
 			val = append([]byte(oldHdr[1]), '\n')
 		}
-		for c := <-data; c != '\n'; c = <-data {
+		for {
+			var ok bool
+			c, ok = <-data
+			if !ok {
+				return [2]string{}, size, io.EOF
+			}
+			if c == '\n' {
+				break
+			}
 			val = append(val, c)
 			size++
 		}
@@ -552,7 +609,14 @@ func parseGitCommitHdr(oldHdr [2]string, data <-chan byte) ([2]string, int, erro
 func parseGitCommitMsg(data <-chan byte, l int) (string, error) {
 	msg := make([]byte, 0, l)
 
-	for c := <-data; c != '\x00'; c = <-data {
+	for {
+		c, ok := <-data
+		if !ok {
+			return string(msg), io.EOF
+		}
+		if c == '\x00' {
+			break
+		}
 		msg = append(msg, c)
 		l--
 	}
@@ -578,7 +642,7 @@ func parseGitCommit(data <-chan byte) (GitCommit, error) {
 		var hdr [2]string
 		hdr, size, err := parseGitCommitHdr(hdr, data)
 		if err != nil {
-			return GitCommit{}, nil
+			return GitCommit{}, err
 		}
 		l -= size
 
@@ -599,14 +663,28 @@ func parseGitCommit(data <-chan byte) (GitCommit, error) {
 func parseTreeEntry(data <-chan byte, hashLen int) (GitTreeEntry, error) {
 	var e GitTreeEntry
 
-	for c := <-data; c != ' '; c = <-data {
+	for {
+		c, ok := <-data
+		if !ok {
+			return e, io.EOF
+		}
+		if c == ' ' {
+			break
+		}
 		e.mode = e.mode*8 + int(c-'0')
 		e.size++
 	}
 	e.size++
 
 	name := make([]byte, 0, 128)
-	for c := <-data; c != '\x00'; c = <-data {
+	for {
+		c, ok := <-data
+		if !ok {
+			return e, io.EOF
+		}
+		if c == '\x00' {
+			break
+		}
 		name = append(name, c)
 		e.size++
 	}
@@ -617,7 +695,10 @@ func parseTreeEntry(data <-chan byte, hashLen int) (GitTreeEntry, error) {
 
 	hash := make([]byte, 0, hashLen*2)
 	for range hashLen {
-		c := <-data
+		c, ok := <-data
+		if !ok {
+			return e, io.EOF
+		}
 		hash = append(hash, hexBinToAscii[((c&0xF0)>>4)], hexBinToAscii[c&0xF])
 	}
 	e.hash = string(hash)
@@ -638,13 +719,16 @@ func parseGitTree(data <-chan byte) (GitTree, error) {
 	for parsedLen < hdr.size {
 		entry, err := parseTreeEntry(data, len(hdr.hash)/2)
 		if err != nil {
-			return GitTree{}, nil
+			return GitTree{}, err
 		}
 
 		t.items = append(t.items, entry)
 		parsedLen += entry.size
 	}
-	c := <-data // \0 read
+	c, ok := <-data // \0 read
+	if !ok {
+		return t, io.EOF
+	}
 
 	if c != '\x00' {
 		return t, fmt.Errorf("Unexpected character during git tree data read")
@@ -665,9 +749,16 @@ func parseGitBlob(data <-chan byte) ([]byte, error) {
 
 	d := make([]byte, hdr.size)
 	for l := 0; l < hdr.size; l++ {
-		d[l] = <-data
+		var ok bool
+		d[l], ok = <-data
+		if !ok {
+			return d, io.EOF
+		}
+	}
+	eob, ok := <-data
+	if !ok {
+		return d, io.EOF
 	}
-	eob := <-data
 	if eob != '\x00' {
 		return d, fmt.Errorf("invalid byte read in parseGitBlob")
 	}
@@ -679,16 +770,25 @@ func (e *GitHandlerImpl) GitParseCommits(cwd string, commitIDs []string) (parsed
 	var done sync.Mutex
 
 	done.Lock()
-	data_in, data_out := ChanIO{make(chan byte)}, ChanIO{make(chan byte)}
+	done_signal := make(chan struct{})
+	var once sync.Once
+	close_done := func() {
+		once.Do(func() {
+			close(done_signal)
+		})
+	}
+
+	data_in, data_out := ChanIO{make(chan byte), done_signal}, ChanIO{make(chan byte), done_signal}
 	parsedCommits = make([]GitCommit, 0, len(commitIDs))
 
 	go func() {
 		defer done.Unlock()
+		defer close_done()
 		defer close(data_out.ch)
 
 		for _, id := range commitIDs {
 			data_out.Write([]byte(id))
-			data_out.ch <- '\x00'
+			data_out.Write([]byte{0})
 			c, e := parseGitCommit(data_in.ch)
 			if e != nil {
 				err = fmt.Errorf("Error parsing git commit: %w", e)
@@ -715,12 +815,14 @@ func (e *GitHandlerImpl) GitParseCommits(cwd string, commitIDs []string) (parsed
 	LogDebug("command run:", cmd.Args)
 	if e := cmd.Run(); e != nil {
 		LogError(e)
+		close_done()
 		close(data_in.ch)
-		close(data_out.ch)
 		return nil, e
 	}
 
 	done.Lock()
+	close_done()
+	close(data_in.ch)
 	return
 }
 
@@ -729,15 +831,21 @@ func (e *GitHandlerImpl) GitCatFile(cwd, commitId, filename string) (data []byte
 	var done sync.Mutex
 
 	done.Lock()
-	data_in, data_out := ChanIO{make(chan byte)}, ChanIO{make(chan byte)}
+	done_signal := make(chan struct{})
+	var once sync.Once
+	close_done := func() {
+		once.Do(func() {
+			close(done_signal)
+		})
+	}
+	data_in, data_out := ChanIO{make(chan byte), done_signal}, ChanIO{make(chan byte), done_signal}
 
 	go func() {
 		defer done.Unlock()
+		defer close_done()
 		defer close(data_out.ch)
-
 		data_out.Write([]byte(commitId))
-		data_out.ch <- '\x00'
-
+		data_out.Write([]byte{0})
 		var c GitCommit
 		c, err = parseGitCommit(data_in.ch)
 		if err != nil {
@@ -745,11 +853,9 @@ func (e *GitHandlerImpl) GitCatFile(cwd, commitId, filename string) (data []byte
 			return
 		}
 		data_out.Write([]byte(c.Tree))
-		data_out.ch <- '\x00'
-
+		data_out.Write([]byte{0})
 		var tree GitTree
 		tree, err = parseGitTree(data_in.ch)
-
 		if err != nil {
 			LogError("Error parsing git tree:", err)
 			return
@@ -759,7 +865,7 @@ func (e *GitHandlerImpl) GitCatFile(cwd, commitId, filename string) (data []byte
 			if te.isBlob() && te.name == filename {
 				LogInfo("blob", te.hash)
 				data_out.Write([]byte(te.hash))
-				data_out.ch <- '\x00'
+				data_out.Write([]byte{0})
 				data, err = parseGitBlob(data_in.ch)
 				return
 			}
@@ -784,11 +890,13 @@ func (e *GitHandlerImpl) GitCatFile(cwd, commitId, filename string) (data []byte
 	LogDebug("command run:", cmd.Args)
 	if e := cmd.Run(); e != nil {
 		LogError(e)
+		close_done()
 		close(data_in.ch)
-		close(data_out.ch)
 		return nil, e
 	}
 	done.Lock()
+	close_done()
+	close(data_in.ch)
 	return
 }
 
@@ -798,16 +906,24 @@ func (e *GitHandlerImpl) GitDirectoryList(gitPath, commitId string) (directoryLi
 	directoryList = make(map[string]string)
 
 	done.Lock()
-	data_in, data_out := ChanIO{make(chan byte)}, ChanIO{make(chan byte)}
+	done_signal := make(chan struct{})
+	var once sync.Once
+	close_done := func() {
+		once.Do(func() {
+			close(done_signal)
+		})
+	}
+	data_in, data_out := ChanIO{make(chan byte), done_signal}, ChanIO{make(chan byte), done_signal}
 
 	LogDebug("Getting directory for:", commitId)
 
 	go func() {
 		defer done.Unlock()
+		defer close_done()
 		defer close(data_out.ch)
 
 		data_out.Write([]byte(commitId))
-		data_out.ch <- '\x00'
+		data_out.Write([]byte{0})
 		var c GitCommit
 		c, err = parseGitCommit(data_in.ch)
 		if err != nil {
@@ -823,7 +939,7 @@ func (e *GitHandlerImpl) GitDirectoryList(gitPath, commitId string) (directoryLi
 				delete(trees, p)
 
 				data_out.Write([]byte(tree))
-				data_out.ch <- '\x00'
+				data_out.Write([]byte{0})
 				var tree GitTree
 				tree, err = parseGitTree(data_in.ch)
 
@@ -857,12 +973,14 @@ func (e *GitHandlerImpl) GitDirectoryList(gitPath, commitId string) (directoryLi
 	LogDebug("command run:", cmd.Args)
 	if e := cmd.Run(); e != nil {
 		LogError(e)
+		close_done()
 		close(data_in.ch)
-		close(data_out.ch)
 		return directoryList, e
 	}
 
 	done.Lock()
+	close_done()
+	close(data_in.ch)
 	return directoryList, err
 }
 
@@ -872,7 +990,14 @@ func (e *GitHandlerImpl) GitDirectoryContentList(gitPath, commitId string) (dire
 	directoryList = make(map[string]string)
 
 	done.Lock()
-	data_in, data_out := ChanIO{make(chan byte)}, ChanIO{make(chan byte)}
+	done_signal := make(chan struct{})
+	var once sync.Once
+	close_done := func() {
+		once.Do(func() {
+			close(done_signal)
+		})
+	}
+	data_in, data_out := ChanIO{make(chan byte), done_signal}, ChanIO{make(chan byte), done_signal}
 
 	LogDebug("Getting directory content for:", commitId)
 
@@ -881,7 +1006,7 @@ func (e *GitHandlerImpl) GitDirectoryContentList(gitPath, commitId string) (dire
 		defer close(data_out.ch)
 
 		data_out.Write([]byte(commitId))
-		data_out.ch <- '\x00'
+		data_out.Write([]byte{0})
 		var c GitCommit
 		c, err = parseGitCommit(data_in.ch)
 		if err != nil {
@@ -897,7 +1022,7 @@ func (e *GitHandlerImpl) GitDirectoryContentList(gitPath, commitId string) (dire
 				delete(trees, p)
 
 				data_out.Write([]byte(tree))
-				data_out.ch <- '\x00'
+				data_out.Write([]byte{0})
 				var tree GitTree
 				tree, err = parseGitTree(data_in.ch)
 
@@ -933,12 +1058,14 @@ func (e *GitHandlerImpl) GitDirectoryContentList(gitPath, commitId string) (dire
 	LogDebug("command run:", cmd.Args)
 	if e := cmd.Run(); e != nil {
 		LogError(e)
+		close_done()
 		close(data_in.ch)
-		close(data_out.ch)
 		return directoryList, e
 	}
 
 	done.Lock()
+	close_done()
+	close(data_in.ch)
 	return directoryList, err
 }
 
@@ -948,16 +1075,24 @@ func (e *GitHandlerImpl) GitSubmoduleList(gitPath, commitId string) (submoduleLi
 	submoduleList = make(map[string]string)
 
 	done.Lock()
-	data_in, data_out := ChanIO{make(chan byte)}, ChanIO{make(chan byte)}
+	done_signal := make(chan struct{})
+	var once sync.Once
+	close_done := func() {
+		once.Do(func() {
+			close(done_signal)
+		})
+	}
+	data_in, data_out := ChanIO{make(chan byte), done_signal}, ChanIO{make(chan byte), done_signal}
 
 	LogDebug("Getting submodules for:", commitId)
 
 	go func() {
 		defer done.Unlock()
+		defer close_done()
 		defer close(data_out.ch)
 
 		data_out.Write([]byte(commitId))
-		data_out.ch <- '\x00'
+		data_out.Write([]byte{0})
 		var c GitCommit
 		c, err = parseGitCommit(data_in.ch)
 		if err != nil {
@@ -973,7 +1108,7 @@ func (e *GitHandlerImpl) GitSubmoduleList(gitPath, commitId string) (submoduleLi
 				delete(trees, p)
 
 				data_out.Write([]byte(tree))
-				data_out.ch <- '\x00'
+				data_out.Write([]byte{0})
 				var tree GitTree
 				tree, err = parseGitTree(data_in.ch)
 
@@ -1010,17 +1145,26 @@ func (e *GitHandlerImpl) GitSubmoduleList(gitPath, commitId string) (submoduleLi
 	LogDebug("command run:", cmd.Args)
 	if e := cmd.Run(); e != nil {
 		LogError(e)
+		close_done()
 		close(data_in.ch)
-		close(data_out.ch)
 		return submoduleList, e
 	}
 
 	done.Lock()
+	close_done()
+	close(data_in.ch)
 	return submoduleList, err
 }
 
 func (e *GitHandlerImpl) GitSubmoduleCommitId(cwd, packageName, commitId string) (subCommitId string, valid bool) {
-	data_in, data_out := ChanIO{make(chan byte)}, ChanIO{make(chan byte)}
+	done_signal := make(chan struct{})
+	var once sync.Once
+	close_done := func() {
+		once.Do(func() {
+			close(done_signal)
+		})
+	}
+	data_in, data_out := ChanIO{make(chan byte), done_signal}, ChanIO{make(chan byte), done_signal}
 	var wg sync.WaitGroup
 
 	wg.Add(1)
@@ -1036,17 +1180,18 @@ func (e *GitHandlerImpl) GitSubmoduleCommitId(cwd, packageName, commitId string)
 		}()
 
 		defer wg.Done()
+		defer close_done()
 		defer close(data_out.ch)
 
 		data_out.Write([]byte(commitId))
-		data_out.ch <- '\x00'
+		data_out.Write([]byte{0})
 		c, err := parseGitCommit(data_in.ch)
 		if err != nil {
 			LogError("Error parsing git commit:", err)
 			panic(err)
 		}
 		data_out.Write([]byte(c.Tree))
-		data_out.ch <- '\x00'
+		data_out.Write([]byte{0})
 		tree, err := parseGitTree(data_in.ch)
 
 		if err != nil {
@@ -1078,12 +1223,14 @@ func (e *GitHandlerImpl) GitSubmoduleCommitId(cwd, packageName, commitId string)
 	LogDebug("command run:", cmd.Args)
 	if e := cmd.Run(); e != nil {
 		LogError(e)
+		close_done()
 		close(data_in.ch)
-		close(data_out.ch)
 		return subCommitId, false
 	}
 
 	wg.Wait()
+	close_done()
+	close(data_in.ch)
 	return subCommitId, len(subCommitId) > 0
 }
 

common/git_utils_test.go

@@ -28,6 +28,7 @@ import (
 	"slices"
 	"strings"
 	"testing"
+	"time"
 )
 
 func TestGitClone(t *testing.T) {
@@ -717,3 +718,44 @@ func TestGitDirectoryListRepro(t *testing.T) {
 		t.Errorf("Expected 'subdir' in directory list, got %v", dirs)
 	}
 }
+
+func TestGitDeadlockFix(t *testing.T) {
+	gitDir := t.TempDir()
+	testDir, _ := os.Getwd()
+
+	cmd := exec.Command("/usr/bin/bash", path.Join(testDir, "tsetup.sh"))
+	cmd.Dir = gitDir
+	_, err := cmd.CombinedOutput()
+
+	gh, err := AllocateGitWorkTree(gitDir, "Test", "test@example.com")
+	if err != nil {
+		t.Fatal(err)
+	}
+	h, err := gh.ReadExistingPath(".")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer h.Close()
+
+	// Use a blob ID to trigger error in GitParseCommits
+	// This ensures that the function returns error immediately and doesn't deadlock
+	blobId := "81aba862107f1e2f5312e165453955485f424612f313d6c2fb1b31fef9f82a14"
+
+	done := make(chan error)
+	go func() {
+		_, err := h.GitParseCommits("", []string{blobId})
+		done <- err
+	}()
+
+	select {
+	case err := <-done:
+		if err == nil {
+			t.Error("Expected error from GitParseCommits with blob ID, got nil")
+		} else {
+			// This is expected
+			t.Logf("Got expected error: %v", err)
+		}
+	case <-time.After(2 * time.Second):
+		t.Fatal("GitParseCommits deadlocked! Fix is NOT working.")
+	}
+}