[Bugfix] Match WeightsMapper stacked remaps on path components#48564
[Bugfix] Match WeightsMapper stacked remaps on path components#48564vdabholkar-together wants to merge 2 commits into
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orig_to_new_stacked did a raw substring replace and kept scanning, so q_proj -> qkv_proj was then rewritten by the v_proj entry into qkqkv_proj, and the q/k shard ids were overwritten with v. This broke weight loading for MiniCPM-V-4.6 on v0.25.0. Match stacked keys as dotted path components and stop after the first hit, preferring longer (qualified) keys over short aliases. Fixes vllm-project#48423 Fixes vllm-project#48449 Signed-off-by: vdabholkar-together <245015005+vdabholkar-together@users.noreply.github.com> Co-authored-by: Cursor <cursoragent@cursor.com> Signed-off-by: <>
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Purpose
Fixes #48423
Fixes #48449
WeightsMapper._map_name_with_shardmatchesorig_to_new_stackedkeys as raw substrings and keeps scanning after a hit. With mappings like MiniCPM-V-4.6's ViT attention (q_proj/k_proj/v_proj->qkv_proj), a name such as...self_attn.q_proj.weightis first rewritten to...qkv_proj.weight, and then thev_projentry matches inside the freshly writtenqkv_proj, producing...qkqkv_proj.weightand overwriting theq/kshard id withv. This breaks weight loading for MiniCPM-V-4.6 on v0.25.0 (KeyError/garbage output depending on path).This PR changes stacked remapping to:
v_projno longer matches insideqkv_proj),No behavior change for existing dotted-style mappings (
.q_projetc.); already-fused names likeqkv_proj.weightnow pass through untouched.Not duplicating existing work: no open PR addresses #48423/#48449 (checked open PRs referencing the issues and
WeightsMapper).Test Plan
Added regression tests in
tests/model_executor/test_weight_utils.py::TestWeightsMapperStackedcovering:q/k/v_proj->qkv_projwith correct shard ids, andqkv_proj/out_projleft untouched,gate_proj/up_proj->gate_up_proj,Test Result
All tests in
tests/model_executor/test_weight_utils.pypass locally (CPU), including the newTestWeightsMapperStackedcases.pre-commit(ruff, mypy, etc.) passes on the changed files.