[PATCH v2 3/5] odb/source: let callers discern missing and corrupt objects

@@ -440,6 +440,8 @@ enum odb_read_status {
 	ODB_READ_OK = 0,
 	/* The read resulted in a generic error. */
 	ODB_READ_ERROR = -1,
+	/* The object could not be found. */
+	ODB_READ_NOT_FOUND = -2,
 };
 
 /*

@@ -65,12 +65,26 @@ static enum odb_read_status odb_source_files_read_object_info(struct odb_source
 							      enum object_info_flags flags)
 {
 	struct odb_source_files *files = odb_source_files_downcast(source);
+	enum odb_read_status ret_packed, ret_loose;
 
-	if (!odb_source_read_object_info(&files->packed->base, oid, oi, flags) ||
-	    !odb_source_read_object_info(&files->loose->base, oid, oi, flags))
+	ret_packed = odb_source_read_object_info(&files->packed->base, oid, oi, flags);
+	if (!ret_packed)
 		return 0;
 
-	return -1;
+	ret_loose = odb_source_read_object_info(&files->loose->base, oid, oi, flags);
+	if (!ret_loose)
+		return 0;
+
+	/*
+	 * Reading the packed object may have failed even though the object
+	 * exists, for example because it is corrupt. Report this failure to
+	 * the caller in case neither of the sources was able to read the
+	 * object, and prefer the error of the packed source in case both
+	 * reads have failed.
+	 */
+	if (ret_packed != ODB_READ_NOT_FOUND)
+		return ret_packed;
+	return ret_loose;
 }
 
 static int odb_source_files_read_object_stream(struct odb_read_stream **out,

@@ -66,7 +66,7 @@ static enum odb_read_status odb_source_inmemory_read_object_info(struct odb_sour
 
 	object = find_cached_object(inmemory, oid);
 	if (!object)
-		return -1;
+		return ODB_READ_NOT_FOUND;
 
 	populate_object_info(inmemory, oi, object);
 	return 0;

@@ -91,11 +91,16 @@ static int read_object_info_from_path(struct odb_source_loose *loose,
 		struct stat st;
 
 		if ((!oi || (!oi->disk_sizep && !oi->mtimep)) && (flags & OBJECT_INFO_QUICK)) {
-			ret = quick_has_loose(loose, oid) ? 0 : -1;
+			ret = quick_has_loose(loose, oid) ? 0 : ODB_READ_NOT_FOUND;
 			goto out;
 		}
 
 		if (lstat(path, &st) < 0) {
+			if (errno == ENOENT) {
+				ret = ODB_READ_NOT_FOUND;
+				goto out;
+			}
+
 			ret = -1;
 			goto out;
 		}

@@ -113,9 +118,12 @@ static int read_object_info_from_path(struct odb_source_loose *loose,
 
 	fd = git_open(path);
 	if (fd < 0) {
-		if (errno != ENOENT)
-			error_errno(_("unable to open loose object %s"), oid_to_hex(oid));
-		ret = -1;
+		if (errno == ENOENT) {
+			ret = ODB_READ_NOT_FOUND;
+			goto out;
+		}
+
+		ret = error_errno(_("unable to open loose object %s"), oid_to_hex(oid));
 		goto out;
 	}
 

@@ -155,7 +163,7 @@ static int read_object_info_from_path(struct odb_source_loose *loose,
 
 		if (parse_loose_header(hdr, oi) < 0) {
 			ret = error(_("unable to parse %s header"), oid_to_hex(oid));
-			goto corrupt;
+			goto out;
 		}
 
 		if (*oi->typep < 0)

@@ -165,7 +173,7 @@ static int read_object_info_from_path(struct odb_source_loose *loose,
 			*oi->contentp = unpack_loose_rest(&stream, hdr, *oi->sizep, oid);
 			if (!*oi->contentp) {
 				ret = -1;
-				goto corrupt;
+				goto out;
 			}
 		}
 

@@ -173,21 +181,20 @@ static int read_object_info_from_path(struct odb_source_loose *loose,
 	case ULHR_BAD:
 		ret = error(_("unable to unpack %s header"),
 			    oid_to_hex(oid));
-		goto corrupt;
+		goto out;
 	case ULHR_TOO_LONG:
 		ret = error(_("header for %s too long, exceeds %d bytes"),
 			    oid_to_hex(oid), MAX_HEADER_LEN);
-		goto corrupt;
+		goto out;
 	}
 
 	ret = 0;
 
-corrupt:
-	if (ret && (flags & OBJECT_INFO_DIE_IF_CORRUPT))
+out:
+	if (ret && ret != ODB_READ_NOT_FOUND && (flags & OBJECT_INFO_DIE_IF_CORRUPT))
 		die(_("loose object %s (stored in %s) is corrupt"),
 		    oid_to_hex(oid), path);
 
-out:
 	if (stream_to_end)
 		git_inflate_end(stream_to_end);
 	if (map)

@@ -221,7 +228,7 @@ static enum odb_read_status odb_source_loose_read_object_info(struct odb_source
 	 * second time.
 	 */
 	if (flags & OBJECT_INFO_SECOND_READ)
-		return -1;
+		return ODB_READ_NOT_FOUND;
 
 	odb_loose_path(loose, &buf, oid);
 	return read_object_info_from_path(loose, buf.buf, oid, oi, flags);

@@ -61,7 +61,7 @@ static enum odb_read_status odb_source_packed_read_object_info(struct odb_source
 		 */
 		if (bad_pack)
 			return -1;
-		return 1;
+		return ODB_READ_NOT_FOUND;
 	}
 
 	/*

@@ -72,7 +72,8 @@ void test_odb_inmemory__read_missing_object(void)
 	const char *end;
 
 	cl_must_pass(parse_oid_hex_algop(RANDOM_OID, &oid, &end, repo.hash_algo));
-	cl_must_fail(odb_source_read_object_info(&source->base, &oid, NULL, 0));
+	cl_assert_equal_i(odb_source_read_object_info(&source->base, &oid, NULL, 0),
+			  ODB_READ_NOT_FOUND);
 
 	odb_source_free(&source->base);
 }