object: Fix error handling

1 files changed, 21 insertions, 5 deletions

diff --git a/object/parse.go b/object/parse.go
index 3a2b5eaa..a4d0d350 100644
--- a/object/parse.go
+++ b/object/parse.go
@@ -12,7 +12,23 @@ import (
 	// "codeberg.org/lindenii/furgit/object/tree"
 )
 
-// ParseWithHeader parses a loose object in "type size\x00body" format.
+// SizeMismatchError indicates a mismatch
+// between the size expected from the object header
+// and the size of the object.
+type SizeMismatchError struct {
+	Expected int
+	Got      int
+}
+
+func (sizeMismatchError SizeMismatchError) Error() string {
+	return fmt.Sprintf(
+		"object: size mismatch: header says %d bytes, but got %d from body",
+		sizeMismatchError.Expected, sizeMismatchError.Got,
+	)
+}
+
+// ParseWithHeader parses a loose object
+// in "type size\x00body" format.
 //
 //nolint:ireturn
 func ParseWithHeader(raw []byte, algo id.Algorithm) (Object, error) {
@@ -23,7 +39,7 @@ func ParseWithHeader(raw []byte, algo id.Algorithm) (Object, error) {
 
 	body := raw[headerLen:]
 	if uint64(len(body)) != size {
-		return nil, fmt.Errorf("object: size mismatch: header says %d bytes, body has %d", size, len(body))
+		return nil, SizeMismatchError{Expected: int(size), Got: len(body)}
 	}
 
 	return ParseWithoutHeader(ty, body, algo)
@@ -35,14 +51,14 @@ func ParseWithHeader(raw []byte, algo id.Algorithm) (Object, error) {
 func ParseWithoutHeader(ty typ.Type, body []byte, algo id.Algorithm) (Object, error) {
 	switch ty {
 	case typ.TypeBlob:
-		return blob.Parse(body)
+		return blob.Parse(body) //nolint:wrapcheck
 	case typ.TypeTree:
 		panic("TODO")
 	case typ.TypeCommit:
-		return commit.Parse(body, algo)
+		return commit.Parse(body, algo) //nolint:wrapcheck
 	case typ.TypeTag:
 		panic("TODO")
 	default:
-		return nil, fmt.Errorf("object: unsupported object type %d", ty)
+		return nil, typ.ErrInvalidType
 	}
 }