A function name used as a VALUE — passed as an argument
(signal(SIGINT, handler), qsort(..., compare)), assigned to a function
pointer or field (ops->recv_cb = my_cb, OnClick := Handler), or placed in
a struct initializer / handler table ({ .recv_cb = my_cb },
{ "get", getCommand }) — produced no edge in ANY of the 19 tree-sitter
languages, so registered callbacks looked dead and their registration
sites were invisible to callers/impact.
This adds table-driven function-as-value capture across all 19 languages
(plus the wrapper forms: &fn, &Cls::method, Java Class::m, Kotlin ::f,
Swift #selector, ObjC @selector, Ruby method(:sym), Scala eta, Pascal
@Handler), gated at extraction (same-file definitions + imported
bindings; C-family file-scope initializers are constant-expression
contexts and skip the gate, which is how redis-style cross-file command
tables resolve), and resolved by a dedicated strategy: function/method
targets only, same-file first, unique-or-drop cross-file, no fuzzy
fallback ever. Edges persist as kind 'references' with metadata.fnRef,
so getCallers/getImpactRadius surface them with zero graph-layer
changes; MCP callers/callees label them "via callback registration".
Precision rules bought by real-repo false positives (full A/B record in
docs/design/function-ref-capture.md): C++ is &-explicit outside
file-scope tables (fmt's begin/out/size collisions; out-of-line member
defs are function-kind); TS/JS/Python bare ids resolve to functions only
(TS class fields extract as method-kind — pre-existing quirk); Swift
refuses same-file method overload-families; param-forward shapes
(this.x = x, value: value) and destructuring are skipped; minified
bundles (*.min.js) produce no candidates.
Validated on 17 public OSS repos (redis, excalidraw, gin, bytes, okhttp,
okio, Alamofire, flask, sinatra, Newtonsoft.Json, scopt, provider,
busted, Fusion, AFNetworking, PascalCoin, fmt): node counts identical,
zero calls edges lost or gained, references strictly additive
(+3,200 registration edges total), precision spot-checked by reading
sampled source lines (redis 30/30, flask 8/8). Deliberately NOT covered:
indirect-dispatch resolution (o->cb(x) → impl) — that needs data-flow
through struct fields, and a wrong edge is worse than none.
EXTRACTION_VERSION 18 → 19 (re-index to benefit).
Closes#756
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
