gitpipe: Handle error in LsTree skip function

Change the prototype of the gitpipe.LsTree skipResult function so it
also can return an error and the gitpipe can be aborted.

3 files changed, 33 insertions, 8 deletions

diff --git a/internal/git/gitpipe/ls_tree.go b/internal/git/gitpipe/ls_tree.go
index b48489e4f..38c15a8c7 100644
--- a/internal/git/gitpipe/ls_tree.go
+++ b/internal/git/gitpipe/ls_tree.go
@@ -16,7 +16,7 @@ import (
 type lsTreeConfig struct {
 	recursive  bool
 	typeFilter func(*lstree.Entry) bool
-	skipResult func(*RevisionResult) bool
+	skipResult func(*RevisionResult) (bool, error)
 }
 
 // LsTreeOption is an option for the LsTree pipeline step.
@@ -39,7 +39,7 @@ func LsTreeWithBlobFilter() LsTreeOption {
 // LsTreeWithSkip will execute the given function for each RevisionResult processed by the
 // pipeline. If the callback returns `true`, then the object will be skipped and not passed down
 // the pipeline.
-func LsTreeWithSkip(skipResult func(*RevisionResult) bool) LsTreeOption {
+func LsTreeWithSkip(skipResult func(*RevisionResult) (bool, error)) LsTreeOption {
 	return func(cfg *lsTreeConfig) {
 		cfg.skipResult = skipResult
 	}
@@ -119,8 +119,17 @@ func LsTree(
 				ObjectName: []byte(entry.Path),
 			}
 
-			if cfg.skipResult != nil && cfg.skipResult(&result) {
-				continue
+			if cfg.skipResult != nil {
+				skip, err := cfg.skipResult(&result)
+				if err != nil {
+					sendRevisionResult(ctx, resultChan, RevisionResult{
+						err: fmt.Errorf("ls-tree skip: %q", err),
+					})
+					return
+				}
+				if skip {
+					continue
+				}
 			}
 
 			if isDone := sendRevisionResult(ctx, resultChan, result); isDone {
diff --git a/internal/git/gitpipe/ls_tree_test.go b/internal/git/gitpipe/ls_tree_test.go
index 52984a4d1..7ebc10316 100644
--- a/internal/git/gitpipe/ls_tree_test.go
+++ b/internal/git/gitpipe/ls_tree_test.go
@@ -170,12 +170,28 @@ func TestLsTree(t *testing.T) {
 				}
 			},
 			options: []LsTreeOption{
-				LsTreeWithSkip(func(r *RevisionResult) bool {
-					return bytes.Equal(r.ObjectName, []byte(".gitignore"))
+				LsTreeWithSkip(func(r *RevisionResult) (bool, error) {
+					return bytes.Equal(r.ObjectName, []byte(".gitignore")), nil
 				}),
 			},
 		},
 		{
+			desc: "with skip failure",
+			setup: func(t *testing.T, repoPath string) (git.Revision, []RevisionResult) {
+				tree := gittest.WriteTree(t, cfg, repoPath, []gittest.TreeEntry{
+					{Path: "README.md", Mode: "100644", Content: "Hello world"},
+				})
+
+				return tree.Revision(), nil
+			},
+			options: []LsTreeOption{
+				LsTreeWithSkip(func(r *RevisionResult) (bool, error) {
+					return true, errors.New("broken")
+				}),
+			},
+			expectedErr: errors.New(`ls-tree skip: "broken"`),
+		},
+		{
 			desc: "invalid revision",
 			setup: func(t *testing.T, repoPath string) (git.Revision, []RevisionResult) {
 				return "refs/heads/does-not-exist", nil
diff --git a/internal/gitaly/linguist/linguist.go b/internal/gitaly/linguist/linguist.go
index 8083bfea6..d032c3f9f 100644
--- a/internal/gitaly/linguist/linguist.go
+++ b/internal/gitaly/linguist/linguist.go
@@ -136,9 +136,9 @@ func (inst *Instance) enryStats(ctx context.Context, commitID string) (ByteCount
 	if full {
 		stats = newLanguageStats()
 
-		skipFunc := func(result *gitpipe.RevisionResult) bool {
+		skipFunc := func(result *gitpipe.RevisionResult) (bool, error) {
 			// Skip files that are an excluded filetype based on filename.
-			return newFileInstance(string(result.ObjectName), attrMatcher).IsExcluded()
+			return newFileInstance(string(result.ObjectName), attrMatcher).IsExcluded(), nil
 		}
 
 		// Full recalculation is needed, so get all the files for the