andrew/libakgl
1
0
Fork 0
Code Issues 67 Pull Requests Actions Packages Projects Releases Wiki Activity

Report the failures that used to be crashes

Browse Source 
Closes Defects items 30 and 31 and Known-and-still-open items 1, 2, 5, 9 and 11.

Both string accessors in json_helpers.c ended their ATTEMPT block with
FINISH(errctx, false), which swallows the failure, and then strncpy'd through
the pointer akgl_heap_next_string never set. So the one condition the pool
exists to report -- it is full, which in practice means something is not
releasing -- arrived as a segfault somewhere else entirely. It is
FINISH(errctx, true) now, and tests/json_helpers.c claims every slot and
asserts AKGL_ERR_HEAP comes back out of both. That test segfaults against the
old code, which is also how the tilemap leak test in the previous commit
confirmed this one.

akgl_tilemap_release tested layers[i].texture and destroyed
tilesets[i].texture, so every tileset texture was freed twice on one release
and no image layer's texture was freed at all. Pointers are cleared as they go,
so a second release is safe instead of a use-after-free.

akgl_game_update_fps called game.lowfpsfunc() unguarded, on a path taken on
frame one because fps is 0 for the first second. Only akgl_game_init installs
it, and renderer.h documents the other path deliberately -- a host that owns
its window binds a backend instead. It installs the default when it finds NULL.

akgl_controller_pushmap and akgl_controller_default checked only the upper
bound, so a negative id indexed before akgl_controlmaps.

The two test-harness helpers were quietly worthless. akgl_render_and_compare
drew t1 on both passes, so it always reported a match and every image assertion
built on it asserted nothing; and akgl_compare_sdl_surfaces memcmp'd
s1->pitch * s1->h bytes out of both surfaces without checking that the second
was the same size, so a smaller one was read past its end. Both fixed, both
tested. tests/util.c also now calls the collide-point test it has defined and
never run.

25/25 pass, memcheck clean, reindent --check and check_error_protocol clean.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
This commit is contained in:
Andrew Kesterson
2026-08-01 00:32:11 -04:00
parent 230278d303
commit 21d69192e3
12 changed files with 309 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

71
tests/json_helpers.c
View File

@@ -56,6 +56,76 @@ static akerr_ErrorContext *load_fixture(void)
* could safely get wrong depended on which typed accessor they happened to
* call -- and the ones that crashed were the ones used most.
*/
/**
* @brief An exhausted string pool must report AKGL_ERR_HEAP, not crash.
*
* Both string accessors ended their ATTEMPT block with `FINISH(errctx, false)`,
* which swallows the failure instead of passing it up, and then ran
* `strncpy(&(*dest)->data, ...)` through the pointer akgl_heap_next_string
* never set. So the one condition the pool is designed to report -- it is full,
* usually because something is not releasing -- arrived as a segfault inside
* strncpy.
*
* This is what TODO.md Performance item 29 looked like from the outside: not
* "the tilemap loader leaks five strings a load", but a crash somewhere else
* entirely, fifty levels later.
*/
akerr_ErrorContext *test_json_string_accessor_reports_pool_exhaustion(void)
{
PREPARE_ERROR(e);
akgl_String *claimed[AKGL_MAX_HEAP_STRING];
akgl_String *dest = NULL;
json_t *strings = NULL;
int held = 0;
int i = 0;
memset(&claimed, 0x00, sizeof(claimed));
ATTEMPT {
CATCH(e, akgl_get_json_array_value(fixture, "strings", &strings));
// Take every slot the pool has. Whatever else is holding one already
// simply means this stops sooner.
while ( held < AKGL_MAX_HEAP_STRING ) {
akerr_ErrorContext *claim = akgl_heap_next_string(&claimed[held]);
if ( claim != NULL ) {
claim->handled = true;
claim = akerr_release_error(claim);
claimed[held] = NULL;
break;
}
held += 1;
}
TEST_ASSERT(e, held > 0, "could not claim any pool strings");
TEST_ASSERT(e, test_string_pool_used() == AKGL_MAX_HEAP_STRING,
"the string pool is not full: %d of %d claimed",
test_string_pool_used(), AKGL_MAX_HEAP_STRING);
// dest is NULL, so both accessors have to claim -- and cannot.
dest = NULL;
TEST_EXPECT_STATUS(e, AKGL_ERR_HEAP,
akgl_get_json_string_value(fixture, "name", &dest),
"reading a string with the pool exhausted");
TEST_ASSERT(e, dest == NULL,
"a refused string accessor wrote to its destination");
dest = NULL;
TEST_EXPECT_STATUS(e, AKGL_ERR_HEAP,
akgl_get_json_array_index_string(strings, 0, &dest),
"reading an array string with the pool exhausted");
TEST_ASSERT(e, dest == NULL,
"a refused array string accessor wrote to its destination");
} CLEANUP {
for ( i = 0; i < AKGL_MAX_HEAP_STRING; i++ ) {
if ( claimed[i] != NULL ) {
IGNORE(akgl_heap_release_string(claimed[i]));
}
}
} PROCESS(e) {
} FINISH(e, true);
SUCCEED_RETURN(e);
}
akerr_ErrorContext *test_json_accessor_null_arguments(void)
{
PREPARE_ERROR(e);
@@ -422,6 +492,7 @@ int main(void)
CATCH(errctx, test_json_array_index_accessors());
CATCH(errctx, test_json_type_and_key_errors());
CATCH(errctx, test_json_with_default());
CATCH(errctx, test_json_string_accessor_reports_pool_exhaustion());
} CLEANUP {
if ( fixture != NULL ) {
json_decref(fixture);