object/resolve: Fix error handling; don't substring-match errors v0.1.96

1 files changed, 47 insertions, 5 deletions

diff --git a/object/resolve/path.go b/object/resolve/path.go
index b3e2d642..347c1234 100644
--- a/object/resolve/path.go
+++ b/object/resolve/path.go
@@ -7,6 +7,42 @@ import (
 	"codeberg.org/lindenii/furgit/objectid"
 )
 
+// PathEmptyError indicates that Path received no segments.
+type PathEmptyError struct{}
+
+func (err *PathEmptyError) Error() string {
+	return "object/resolve: empty tree path"
+}
+
+// PathSegmentEmptyError indicates that one path segment is empty.
+type PathSegmentEmptyError struct {
+	Index int
+}
+
+func (err *PathSegmentEmptyError) Error() string {
+	return fmt.Sprintf("object/resolve: empty tree path segment at index %d", err.Index)
+}
+
+// PathNotFoundError indicates that one tree path segment was not found.
+type PathNotFoundError struct {
+	Index int
+	Name  []byte
+}
+
+func (err *PathNotFoundError) Error() string {
+	return fmt.Sprintf("object/resolve: tree entry %q not found at index %d", err.Name, err.Index)
+}
+
+// PathNotTreeError indicates that one intermediate path segment was not a tree.
+type PathNotTreeError struct {
+	Index int
+	Name  []byte
+}
+
+func (err *PathNotTreeError) Error() string {
+	return fmt.Sprintf("object/resolve: path segment %q at index %d is not a tree", err.Name, err.Index)
+}
+
 // Path resolves parts within the tree identified by root and returns the final
 // tree entry.
 //
@@ -17,7 +53,7 @@ import (
 // its object.
 func (r *Resolver) Path(root objectid.ObjectID, parts [][]byte) (object.TreeEntry, error) {
 	if len(parts) == 0 {
-		return object.TreeEntry{}, fmt.Errorf("object/resolve: empty tree path")
+		return object.TreeEntry{}, &PathEmptyError{}
 	}
 
 	current, err := r.PeelToTree(root)
@@ -27,12 +63,15 @@ func (r *Resolver) Path(root objectid.ObjectID, parts [][]byte) (object.TreeEntr
 
 	for i, part := range parts {
 		if len(part) == 0 {
-			return object.TreeEntry{}, fmt.Errorf("object/resolve: empty tree path segment")
+			return object.TreeEntry{}, &PathSegmentEmptyError{Index: i}
 		}
 
 		entry := current.Object().Entry(part)
 		if entry == nil {
-			return object.TreeEntry{}, fmt.Errorf("object/resolve: tree entry %q not found", part)
+			return object.TreeEntry{}, &PathNotFoundError{
+				Index: i,
+				Name:  append([]byte(nil), part...),
+			}
 		}
 
 		if i == len(parts)-1 {
@@ -40,7 +79,10 @@ func (r *Resolver) Path(root objectid.ObjectID, parts [][]byte) (object.TreeEntr
 		}
 
 		if entry.Mode != object.FileModeDir {
-			return object.TreeEntry{}, fmt.Errorf("object/resolve: path segment %q is not a tree", part)
+			return object.TreeEntry{}, &PathNotTreeError{
+				Index: i,
+				Name:  append([]byte(nil), part...),
+			}
 		}
 
 		current, err = r.ExactTree(entry.ID)
@@ -49,5 +91,5 @@ func (r *Resolver) Path(root objectid.ObjectID, parts [][]byte) (object.TreeEntr
 		}
 	}
 
-	return object.TreeEntry{}, fmt.Errorf("object/resolve: tree entry not found")
+	return object.TreeEntry{}, &PathNotFoundError{Index: len(parts) - 1}
 }