René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Fix various bugs in compiler pipeline from bug report","articleBody":"# Bug report\n\n### Bug description:\n\nThis is a sub-issue of https://github.com/python/cpython/issues/146102, details copied from gist:\n\n# Compiler Pipeline (codegen + compile + symtable + flowgraph + assemble) | 6 FIX\n\n## codegen.c (6,632 lines) — 4 FIX\n1. **NULL deref + ref leak in `codegen_setup_annotations_scope` (line 716-720)**: `PyLong_FromLong` result not NULL-checked, passed to `ADDOP_LOAD_CONST` which dereferences it. Also never DECREF'd even on success.\n2. **Ref leak of `mangled` in `codegen_nameop` (line 3280)**: `RETURN_IF_ERROR(scope)` early-returns without DECREF'ing `mangled` from `_PyCompile_MaybeMangle`.\n3. : 7 macro sites between allocation and consumption can early-return, leaking `mangled`.\n4. **Unchecked `_PyCompile_PushFBlock` in `codegen_unwind_fblock_stack` (line 669)**: Return value silently discarded, error lost, frame block stack left inconsistent.\n\n## compile.c (1,772 lines) — 1 FIX\n1. **Ref leak of `orig` in `_PyCompile_TweakInlinedComprehensionScopes` (line 1096-1114)**: `PyDict_GetItemRef` returns new ref in `orig`, never DECREF'd on any path (success or error). Leaks on every inlined comprehension.\n\n## assemble.c (802 lines) — 1 FIX\n1. **`assemble_emit_instr` returns ERROR without exception (line 420-421)**: Bytecode overflow check returns ERROR without `PyErr_NoMemory()` → SystemError.\n\n## symtable.c (3,355 lines) — 0 FIX (clean)\n## flowgraph.c (4,088 lines) — 0 FIX (clean)\n\n### CPython versions tested on:\n\nCPython main branch\n\n### Operating systems tested on:\n\nWindows\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-146443\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/A0su","@type":"Person","name":"A0su"},"datePublished":"2026-03-26T03:42:51.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":4},"url":"https://github.com/146442/cpython/issues/146442"}