Bug fixes

[rsachetto]

---

• File: inotify_helpers.c

• Problem: In check_for_model_file_changes, assigning the return value of read() to size_t length caused an implicit cast to a very large unsigned number on read error (-1), leading to stack overflow. Additionally, attempting to break out of the infinite loop inside a _Noreturn function generated compiler warnings and undefined runtime behavior.

• Fix:

  • Changed length to ssize_t and validated length < 0.
  • Added an #include <errno.h> check: if errno == EINTR (a transient interrupt), the loop safely continues.
  • Implemented automatic recreation/recovery: on any unrecoverable error, the old descriptor is closed, the hash map resources are freed, a new inotify_init() instance is obtained, and it dynamically re-registers file watches for all currently loaded models, allowing monitoring to continue seamlessly without terminating the thread or the shell.

• File: commands.c

• Problem: In unloadall, iterating forward by index through the loaded_models hash map while invoking unload (which deletes entries) caused subsequent keys to shift/reorder within the internal stb_ds dynamic array, leading to skipped deletions or out-of-bounds memory accesses.

• Fix:

  • Replaced the indexed loop with a robust while (shlen(shell_state->loaded_models) > 0) loop, always unloading the first element (index 0) until empty.

• File: commands.c

• Problem: Unloading the active model left a dangling pointer in shell_state->current_model pointing to freed memory, leading to potential use-after-free (UAF) crashes in subsequent shell commands.

• Fix:

  • Added a safety check in unload to explicitly set shell_state->current_model = NULL if the last remaining model is being unloaded.

• File: commands.c

• Problem: Assigning empty or invalid values in the shell (e.g. setodevalue v = ) caused parser errors that returned either NULL or an empty program array. Directly dereferencing program[0] resulted in an immediate segmentation fault due to accessing NULL memory.

• Fix:

  • Added a defensive check if(program == NULL || arrlen(program) == 0) to gracefully return false on parser failure/empty input instead of crashing.

• File: parser.c

• Problem: The global scope checking flag propagation was nested inside case ast_ode_stmt: / case ast_global_stmt: but wrapped in an impossible if(src->tag == ast_assignment_stmt) condition, resulting in dead code. This caused global variables in standard assignment statements to not propagate their .global flag, leading to compiler local-variable shadow-declaration bugs in generated C.

• Fix:

  • Moved the flag propagation logic to its correct block inside case ast_assignment_stmt::

    bool var_is_global = shgeti(p->global_scope, id_name) != -1;
    if(var_is_global) {
        src->assignment_stmt.name->identifier.global = true;
    }

  • Cleaned up the unreachable condition in case ast_ode_stmt:/case ast_global_stmt: to directly check the tag's presence in global_scope.

---