fix: stale slot indices, cascade OOB, pending over-alloc, collect_dependents bounds, size_t format on Windows

- stk_poll: unify load loops to always append on compacted array, removing stale pre-compaction slot indices
- stk_poll: heap-allocate cascade_indices per iteration, removing fixed 256-slot stack bound
- stk_pending_retry: shrink module array to actual count after retry loop completes
- stk_collect_dependents: add capacity parameter and bounds guard before index write
- stk_log_modules: cast module_count to unsigned long for C89 portable %lu on Windows

CHANGELOG.md

@@ -7,6 +7,30 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [1.0.0-pre.8] - 2026-03-08
+
+### Fixed
+- `stk_poll()`: stale index corruption when simultaneous load and unload events occurred in the same poll cycle. New modules were previously loaded into pre-compaction slot indices; they now always append to the compacted array via `module_count + successful_appends`, matching the `append_modules` path. The two load loops have been unified into one.
+- `stk_poll()`: `cascade_indices` was a fixed-size stack array of `STK_PATH_MAX` (256) elements with no bounds check. It is now heap-allocated to `module_count` entries per iteration, eliminating the silent overflow risk.
+- `stk_pending_retry()`: module array was pre-allocated to `module_count + stk_pending_count` but never shrunk when fewer entries loaded than were pending. Now calls `stk_module_realloc_memory(module_count)` after the retry loop completes.
+- `stk_collect_dependents()`: missing bounds guard on the `indices` write: `(*count)++` had no check against the buffer capacity before writing. Added `capacity` parameter (passed as `module_count` from the call site) and a guard that skips the write if the capacity is reached, preventing a silent overflow.
+- `stk_log_modules()`: `%lu` format specifier used with `size_t` is undefined behaviour on platforms where `unsigned long` is narrower than `size_t` (e.g. MSVC 64-bit). Fixed with an explicit `(unsigned long)` cast, preserving C89 compatibility.
+
+## [1.0.0-pre.7] - 2026-03-07
+
+### Fixed
+- `stk_module_load()`: added missing dependency failure logging when a module is deferred to the pending queue.
+
+## [1.0.0-pre.6] - 2026-03-07
+
+### Changed
+- `stk_poll()`: replaced per-module `stk_pending_add()` calls inside the load holes and `append_modules` loops with batch collection followed by a single `stk_pending_add_batch()` call after both loops complete.
+
+## [1.0.0-pre.5] - 2026-03-07
+
+### Changed
+- `stk_init()`: replaced per-module `stk_pending_add()` calls inside the deferred module loop with batch collection followed by a single `stk_pending_add_batch()` call after the loop.
+
 ## [1.0.0-pre.4] - 2026-03-07
 
 ### Changed
@@ -168,7 +192,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Dependency management and versioning not yet implemented
 - API is unstable and subject to change in future releases
 
-[Unreleased]: https://github.com/anth64/stk/compare/v1.0.0-pre.4...HEAD
+[Unreleased]: https://github.com/anth64/stk/compare/v1.0.0-pre.8...HEAD
+[1.0.0-pre.8]: https://github.com/anth64/stk/compare/v1.0.0-pre.7...v1.0.0-pre.8
+[1.0.0-pre.7]: https://github.com/anth64/stk/compare/v1.0.0-pre.6...v1.0.0-pre.7
+[1.0.0-pre.6]: https://github.com/anth64/stk/compare/v1.0.0-pre.5...v1.0.0-pre.6
+[1.0.0-pre.5]: https://github.com/anth64/stk/compare/v1.0.0-pre.4...v1.0.0-pre.5
 [1.0.0-pre.4]: https://github.com/anth64/stk/compare/v1.0.0-pre.3...v1.0.0-pre.4
 [1.0.0-pre.3]: https://github.com/anth64/stk/compare/v1.0.0-pre.2...v1.0.0-pre.3
 [1.0.0-pre.2]: https://github.com/anth64/stk/compare/v1.0.0-pre.1...v1.0.0-pre.2

README.md

@@ -14,7 +14,7 @@ It is designed to run on modern systems running POSIX and Windows using C89.
 - **Hot-swapping** of modules at runtime
 - **Cross-platform** (Linux, BSD, Windows, macOS)
 - **Optional WASM support** for multi-language modules (planned)
-- **Developer tools**: lightweight metadata, logging/tracing, and dependency management (in progress)
+- **Developer tools**: lightweight metadata, logging/tracing, and dependency management
 - **Minimal, portable API**
 
 ---
@@ -234,7 +234,7 @@ stk_init();
 
 ## Project Status
 
-**Current Version:** 1.0.0-pre.4
+**Current Version:** 1.0.0-pre.8
 
 ### What Works
 - Cross-platform module loading and hot-reloading

src/module.c

@@ -563,6 +563,7 @@ unsigned char stk_module_load(const char *path, int index)
 
 	result = stk_validate_dependencies_single(index);
 	if (result != STK_MOD_INIT_SUCCESS) {
+		stk_log_dependency_failures(index, "Deferring");
 		stk_module_discard(index);
 		return result;
 	}
@@ -746,7 +747,7 @@ cleanup:
 	free(result);
 }
 
-void stk_collect_dependents(size_t *indices, size_t *count)
+void stk_collect_dependents(size_t *indices, size_t *count, size_t capacity)
 {
 	size_t i, d;
 	int in_set, changed;
@@ -777,6 +778,8 @@ void stk_collect_dependents(size_t *indices, size_t *count)
 					for (k = 0; k < *count; k++) {
 						if (indices[k] ==
 						    (size_t)dep_index) {
+							if (*count >= capacity)
+								goto next_module;
 							indices[(*count)++] = i;
 							changed = 1;
 							goto next_module;
@@ -1092,6 +1095,9 @@ size_t stk_pending_retry(void)
 	if (stk_pending_count == 0)
 		stk_pending_free();
 
+	if (loaded > 0)
+		stk_module_realloc_memory(module_count);
+
 	return loaded;
 }
 

src/stk.c

@@ -63,7 +63,7 @@ void stk_pending_add_batch(const char (*paths)[STK_PATH_MAX_OS], size_t count);
 void stk_pending_remove(const char *id);
 size_t stk_pending_retry(void);
 void stk_sort_unload_order(size_t *indices, size_t n);
-void stk_collect_dependents(size_t *indices, size_t *count);
+void stk_collect_dependents(size_t *indices, size_t *count, size_t capacity);
 void stk_sort_load_order(int *file_indices, size_t n,
 			 char (*file_names)[STK_PATH_MAX], const char *tmp_dir);
 
@@ -123,7 +123,8 @@ static void stk_log_module(size_t index)
 static void stk_log_modules(void)
 {
 	size_t i;
-	stk_log(STK_LOG_INFO, "Loaded modules (%lu):", module_count);
+	stk_log(STK_LOG_INFO,
+		"Loaded modules (%lu):", (unsigned long)module_count);
 	for (i = 0; i < module_count; i++)
 		stk_log_module(i);
 }
@@ -136,10 +137,11 @@ unsigned char stk_init(void)
 	size_t index, test_count;
 	char full_path[STK_PATH_MAX_OS];
 	char tmp_path[STK_PATH_MAX_OS];
-	char mod_tmp_path[STK_PATH_MAX_OS];
 	int load_result;
 	unsigned char dep_result;
 	size_t *order = NULL;
+	char (*init_batch)[STK_PATH_MAX_OS] = NULL;
+	size_t init_batch_count = 0;
 
 	platform_mkdir(stk_mod_dir);
 	build_path(stk_tmp_dir, sizeof(stk_tmp_dir), stk_mod_dir, stk_tmp_name);
@@ -206,17 +208,25 @@ unsigned char stk_init(void)
 				stk_error_string(dep_result));
 	}
 
+	init_batch = malloc(module_count * sizeof(*init_batch));
+
 	for (j = 0; j < module_count; j++) {
 		index = order ? order[j] : j;
 		dep_result = stk_validate_dependencies_single(index);
 		if (dep_result != STK_MOD_INIT_SUCCESS) {
 			stk_log_dependency_failures(index, "Deferring");
-			build_path(mod_tmp_path, sizeof(mod_tmp_path),
-				   stk_tmp_dir, stk_modules[index].id);
-			strncat(mod_tmp_path, STK_MODULE_EXT,
-				sizeof(mod_tmp_path) - strlen(mod_tmp_path) -
-				    1);
-			stk_pending_add(mod_tmp_path);
+			if (init_batch) {
+				build_path(init_batch[init_batch_count],
+					   sizeof(init_batch[init_batch_count]),
+					   stk_tmp_dir, stk_modules[index].id);
+				strncat(
+				    init_batch[init_batch_count],
+				    STK_MODULE_EXT,
+				    sizeof(init_batch[init_batch_count]) -
+					strlen(init_batch[init_batch_count]) -
+					1);
+				init_batch_count++;
+			}
 			stk_module_discard(index);
 			continue;
 		}
@@ -227,6 +237,14 @@ unsigned char stk_init(void)
 		}
 	}
 
+	if (init_batch_count > 0)
+		stk_pending_add_batch(
+		    (const char (*)[STK_PATH_MAX_OS])init_batch,
+		    init_batch_count);
+
+	free(init_batch);
+	init_batch = NULL;
+
 	if (order) {
 		free(order);
 		order = NULL;
@@ -291,7 +309,7 @@ size_t stk_poll(void)
 		  unload_count = 0;
 	int *reloaded_mod_indices = NULL, *reloaded_mod_file_indices = NULL,
 	    *unloaded_mod_indices = NULL, *loaded_mod_indices = NULL;
-	size_t remaining_loads, new_capacity, holes_to_fill;
+	size_t new_capacity;
 	char full_path[STK_PATH_MAX_OS], tmp_path[STK_PATH_MAX_OS];
 	char mod_id[STK_MOD_ID_BUFFER];
 	int load_result;
@@ -304,16 +322,16 @@ size_t stk_poll(void)
 	size_t index, oi;
 	int is_orig;
 	size_t write;
-	size_t li;
-	int fi;
-	int file_index, mod_index, target_index;
-	size_t cascade_indices[STK_PATH_MAX];
+	int file_index, mod_index;
+	size_t *cascade_indices = NULL;
 	size_t cascade_count;
 	size_t j, k, cascade_write;
 	char (*dep_batch)[STK_PATH_MAX_OS] = NULL;
 	size_t dep_batch_count = 0;
 	char (*cascade_batch)[STK_PATH_MAX_OS] = NULL;
 	size_t cascade_batch_count = 0;
+	char (*load_batch)[STK_PATH_MAX_OS] = NULL;
+	size_t load_batch_count = 0;
 
 	if (module_count > 0) {
 		module_ids = malloc(module_count * sizeof(*module_ids));
@@ -389,8 +407,7 @@ size_t stk_poll(void)
 	goto begin_operations;
 
 handle_grow:
-	remaining_loads = load_count - unload_count;
-	new_capacity = module_count + remaining_loads;
+	new_capacity = module_count + load_count;
 	if (stk_module_realloc_memory(new_capacity) != STK_MOD_INIT_SUCCESS)
 		goto free_poll;
 
@@ -402,7 +419,8 @@ begin_operations:
 		for (i = 0; i < unload_count; i++)
 			unload_order[i] = (size_t)unloaded_mod_indices[i];
 
-		stk_collect_dependents(unload_order, &expanded_count);
+		stk_collect_dependents(unload_order, &expanded_count,
+				       module_count);
 		stk_sort_unload_order(unload_order, expanded_count);
 
 		dep_batch = malloc(expanded_count * sizeof(*dep_batch));
@@ -494,14 +512,12 @@ begin_operations:
 				stk_error_string(load_result));
 	}
 
-	holes_to_fill = (load_count < unload_count) ? load_count : unload_count;
-
-	for (li = 0; li < load_count; li++) {
-		fi = loaded_mod_indices[li];
+	for (i = 0; i < load_count; i++) {
+		file_index = loaded_mod_indices[i];
 		build_path(full_path, sizeof(full_path), stk_mod_dir,
-			   file_list[fi]);
+			   file_list[file_index]);
 		build_path(tmp_path, sizeof(tmp_path), stk_tmp_dir,
-			   file_list[fi]);
+			   file_list[file_index]);
 		platform_copy_file(full_path, tmp_path);
 	}
 
@@ -509,33 +525,10 @@ begin_operations:
 		stk_sort_load_order(loaded_mod_indices, load_count, file_list,
 				    stk_tmp_dir);
 
-	for (i = 0; i < holes_to_fill; ++i) {
-		target_index = unloaded_mod_indices[i];
-		file_index = loaded_mod_indices[i];
+	load_batch = malloc(load_count * sizeof(*load_batch));
+	load_batch_count = 0;
 
-		build_path(tmp_path, sizeof(tmp_path), stk_tmp_dir,
-			   file_list[file_index]);
-
-		load_result = stk_module_load(tmp_path, target_index);
-		if (load_result == STK_MOD_DEP_NOT_FOUND_ERROR ||
-		    load_result == STK_MOD_DEP_VERSION_MISMATCH_ERROR) {
-			stk_pending_add(tmp_path);
-		} else if (load_result != STK_MOD_INIT_SUCCESS) {
-			stk_log(STK_LOG_ERROR, "Failed to load module %s: %s",
-				file_list[file_index],
-				stk_error_string(load_result));
-		} else {
-			module_count++;
-		}
-	}
-
-	if (load_count > unload_count)
-		goto append_modules;
-
-	goto validate_deps;
-
-append_modules:
-	for (; i < load_count; ++i) {
+	for (i = 0; i < load_count; ++i) {
 		file_index = loaded_mod_indices[i];
 
 		build_path(tmp_path, sizeof(tmp_path), stk_tmp_dir,
@@ -545,7 +538,9 @@ append_modules:
 							    successful_appends);
 		if (load_result == STK_MOD_DEP_NOT_FOUND_ERROR ||
 		    load_result == STK_MOD_DEP_VERSION_MISMATCH_ERROR) {
-			stk_pending_add(tmp_path);
+			if (load_batch)
+				memcpy(load_batch[load_batch_count++], tmp_path,
+				       STK_PATH_MAX_OS);
 		} else if (load_result != STK_MOD_INIT_SUCCESS) {
 			stk_log(STK_LOG_ERROR, "Failed to load module %s: %s",
 				file_list[file_index],
@@ -557,9 +552,17 @@ append_modules:
 
 	module_count += successful_appends;
 
-	if (successful_appends < (load_count - holes_to_fill))
+	if (successful_appends < load_count)
 		stk_module_realloc_memory(module_count);
 
+	if (load_batch_count > 0)
+		stk_pending_add_batch(
+		    (const char (*)[STK_PATH_MAX_OS])load_batch,
+		    load_batch_count);
+
+	free(load_batch);
+	load_batch = NULL;
+
 	goto validate_deps;
 
 validate_deps:
@@ -569,6 +572,10 @@ validate_deps:
 	do {
 		cascade_count = 0;
 
+		cascade_indices = malloc(module_count * sizeof(size_t));
+		if (!cascade_indices)
+			break;
+
 		for (j = 0; j < module_count; j++) {
 			if (stk_modules[j].dep_count == 0)
 				continue;
@@ -581,8 +588,11 @@ validate_deps:
 			}
 		}
 
-		if (cascade_count == 0)
+		if (cascade_count == 0) {
+			free(cascade_indices);
+			cascade_indices = NULL;
 			break;
+		}
 
 		cascade_batch = malloc(cascade_count * sizeof(*cascade_batch));
 		cascade_batch_count = 0;
@@ -626,6 +636,9 @@ validate_deps:
 		}
 		module_count = cascade_write;
 
+		free(cascade_indices);
+		cascade_indices = NULL;
+
 	} while (cascade_count > 0);
 
 	if (module_count > 0)