`extract --no-cluster` and the clustered path disagreed on where a
framework-style `#import <Kit/ToolEvent.h>` lands. The clustered path
re-pointed the edge at the header's real file node (`kit_event_toolevent`);
the raw path minted an external stub for the header's bare basename
(`toolevent`) and left the edge on it, so the two write paths of one
extractor produced different graphs for the same corpus.
The raw path only had a normalization map. Normalization cannot bridge
`toolevent` and `kit_event_toolevent` - they are not the same string
modulo case and punctuation - so re-pointing was impossible. The
clustered path resolves it through the pre-migration alias index, which
maps a file's old-stem spellings onto its canonical id (#1504/#1509).
Move that index into a shared `_alias_index` helper and use it in both
paths, so the clustered and the raw write path resolve an endpoint the
same way. The raw path now re-points endpoints BEFORE it mints stubs, so
an import that names a real file is no longer frozen onto a stub minted
for its unresolved spelling; only a genuinely external import
(`<Foundation/Foundation.h>`) still mints one (#2873).
An alias is committed only when exactly one node claims it, so two files
sharing a bare stem stay ambiguous and the import keeps its stub rather
than binding to whichever same-stem file was seen first.
Tests: two unit tests over `finalize_raw_graph_endpoints` (an old-stem
alias resolves to the real file node; an ambiguous alias stays
unresolved) and one end-to-end test that `extract --no-cluster` and the
clustered path agree on the import target. The new tests fail without
this change.
(cherry picked from commit acbec5f5c3)
nothariharan
7598c5dcee