)]}'
{
  "commit": "363be141eb198ab4526ae9d6dedb02b7aa462475",
  "tree": "bff4f86ffbe832d7a36c0d76ff3c1f20951d544c",
  "parents": [
    "cbd8c82b7426322f51654bc54c6dad963f84999a"
  ],
  "author": {
    "name": "Ivan Levkivskyi",
    "email": "levkivskyi@gmail.com",
    "time": "Wed Jun 03 11:22:13 2026 +0100"
  },
  "committer": {
    "name": "GitHub",
    "email": "noreply@github.com",
    "time": "Wed Jun 03 11:22:13 2026 +0100"
  },
  "message": "Fix crash on invalid recursive variadic alias (#21572)\n\nFixes https://github.com/python/mypy/issues/21125\n\nThis one was tricky. This is because the above issue actually exposed\n_two_ different crash scenarios:\n* A crash on invalid constructs like `*tuple[Ts]` (must be\n`*tuple[*Ts]`).\n* An infinite recursion when trying to detect pathological and divergent\naliases.\n\nAnd while working on this I discovered two more cases:\n* A crash where an invalid type (like a union) appears in unpack in a\nrecursive alias definition.\n* A crash on non-normalizeable recursive tuple.\n\nI fix the first by tightening logic in `typeanal.py` w.r.t. where\nexactly a `TypeVarTuple` is allowed. I fix the second and third by\navoiding `get_proper_type()` calls in `expand_type()` for recursive\ntuples. The fourth is the most problematic, and is kind of a fundamental\nthing. This PR only avoids an immediate crash for such aliases. We will\nstill need to update various call sites where we special-case tuples to\nexpect non-normal ones.\n\nCouple more related things:\n* I fix couple issues with `is_recursive` cache invalidation.\n* I added a fast path to `detect_diverging_alias()` to avoid creating\nsets unless really needed.",
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