Ensure error list stays in sync (awslabs#454)

Author: graebm

source/error.c

@@ -159,16 +159,32 @@ void aws_register_error_info(const struct aws_error_info_list *error_info) {
     if (slot_index >= AWS_MAX_ERROR_SLOTS || slot_index < 0) {
         /* This is an NDEBUG build apparently. Kill the process rather than
          * corrupting heap. */
-        fprintf(stderr, "Bad error slot index 0x%016x\n", slot_index);
-        abort();
+        fprintf(stderr, "Bad error slot index %d\n", slot_index);
+        AWS_FATAL_ASSERT(0);
     }
 
+#if DEBUG_BUILD
+    /* Assert that error info entries are in the right order. */
+    for (int i = 1; i < error_info->count; ++i) {
+        const int expected_code = min_range + i;
+        const struct aws_error_info *info = &error_info->error_list[i];
+        if (info->error_code != expected_code) {
+            if (info->error_code) {
+                fprintf(stderr, "Error %s is at wrong index of error info list.\n", info->literal_name);
+            } else {
+                fprintf(stderr, "Error %d is missing from error info list.\n", expected_code);
+            }
+            AWS_FATAL_ASSERT(0);
+        }
+    }
+#endif /* DEBUG_BUILD */
+
     ERROR_SLOTS[slot_index] = error_info;
 }
 
 static int8_t s_error_strings_loaded = 0;
 
-#define AWS_DEFINE_ERROR_INFO_COMMON(C, ES) AWS_DEFINE_ERROR_INFO(C, ES, "libaws-c-common")
+#define AWS_DEFINE_ERROR_INFO_COMMON(C, ES) [(C)-0x0000] = AWS_DEFINE_ERROR_INFO(C, ES, "libaws-c-common")
 
 /* clang-format off */
 static struct aws_error_info errors[] = {

tests/CMakeLists.txt

@@ -33,6 +33,7 @@ add_test_case(error_callback_test)
 add_test_case(unknown_error_code_in_slot_test)
 add_test_case(unknown_error_code_no_slot_test)
 add_test_case(unknown_error_code_range_too_large_test)
+add_test_case(aws_load_error_strings_test)
 
 add_test_case(thread_creation_join_test)
 

tests/error_test.c

@@ -444,6 +444,16 @@ static int s_error_code_cross_thread_test_fn(struct aws_allocator *allocator, vo
     return 0;
 }
 
+static int s_aws_load_error_strings_test(struct aws_allocator *allocator, void *ctx) {
+    (void)allocator;
+    (void)ctx;
+
+    /* Load aws-c-common's actual error info.
+     * This will fail if the error info list is out of sync with the error enums. */
+    aws_load_error_strings();
+    return AWS_OP_SUCCESS;
+}
+
 AWS_TEST_CASE_FIXTURE(
     raise_errors_test,
     s_setup_errors_test_fn,
@@ -486,3 +496,4 @@ AWS_TEST_CASE_FIXTURE(
     s_error_code_cross_thread_test_fn,
     s_teardown_errors_test_fn,
     NULL)
+AWS_TEST_CASE(aws_load_error_strings_test, s_aws_load_error_strings_test)