Martin Vogel 7aa384b401 fix(graph): platform variants keep their path QNs and are related by variant_key ...

42a93202 gave a non-static C-family function under a platform directory
(arch/x86/, src/win/, ...) or file suffix a platform-neutral QN, so the
platform variants of one function shared a node. On the Linux kernel that
merged only 644 of 17,413 such definitions; the other 16,769 lost their
path for nothing (`arch/arm64/mm/init.c` mem_init became
`arch.mm.init.mem_init`, and a lookup by its path QN found nothing),
arches missing from the token list kept their paths, and calls bound to
merged nodes produced impossible arch -> other-arch CALLS.

Every definition keeps its path-derived QN again (the v0.11.0 identity).
The platform-neutral QN is now a key: definitions carrying one get a
`variant_key` node property, and nodes of a project sharing a key are one
variant group. The test-impact walk (store_impact `follow_variant_keys`,
enabled by the test-impact engine) treats a reached variant as reaching its
whole group, at seeding and at every step, so a change confined to the
Windows variant still selects the tests that reach the POSIX variant's
callers. The key is a pure function of a definition's own path, name and
linkage: incremental re-parsing of the changed file writes what a full
index writes. Same-QN variants (#if/#else, Rust cfg, Go build tags,
.c/.h pairs) and their `variants` property are unchanged. No new edge type.

Proof (macOS arm64):
- Linux kernel subset (arch, include, kernel, mm, lib; 27,005 files):
  arch functions whose QN is not under their own path 12,873 -> 0;
  arch/A -> arch/B CALLS 10,353 -> 7,101; 581 variant groups (1,815
  members), each one of the former cross-file merges; the path QN of
  arch/arm64's mem_init resolves.
- This repository: 13 groups (test_impact_tree_{posix,windows},
  mem_override_{posix,win}); before, 22 of 49 platform-path functions had a
  stripped QN.
- New/rewritten tests (RED on the old tree or without the walk
  expansion): conditional_variants cv_c_platform_files,
  cv_c_platform_directories, cv_incremental_platform_files;
  test_impact_engine
  test_impact_engine_platform_variants_reach_each_others_callers;
  store_impact impact_walk_crosses_platform_variants_only_when_asked;
  cv_incremental_variant_partners re-fixtured to Go build tags.
- 18 affected suites: 2710 passed, 4 Windows-only skips.

Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>

2026-10-13 18:33:40 +02:00

..

cbm

fix(graph): platform variants keep their path QNs and are related by variant_key

2026-10-13 18:33:40 +02:00