Go AST query alternatives — 2026-08-10

Status: INCOMPLETE. Issue #6182 tracks real structural-search tool runs and independent resource/cost witnesses.

Capability and workload

internal/astquery.Search, consumed by codesearch ast, parses a Go expression pattern, unifies expression subtrees, binds named metavariables consistently, supports anonymous wildcards, and returns source positions and bindings. Higher-level codesearch trigram, graph, and feature modes are outside this leaf.

Every arm searches identical Go source for eq($X, $X). The corpus has two true calls (alpha, beta), one same-shape call with inconsistent arguments, one string and one comment containing textual decoys, and an unrelated function call. Correctness requires exactly the two ordered source lines and exact X bindings.

Arms

Arm	Class	Local status
fak native Go AST query	native	available
literal text search	tuned no-structure baseline	available, incorrect
Semgrep	external	unavailable
ast-grep	external	unavailable
Comby	external	unavailable
gogrep	external	unavailable

No equivalent first-class fak integration was found. If one appears, it must be added as a separate arm. The literal baseline performs one pass over candidate lines but cannot enforce syntax or repeated-hole consistency. Unavailable tools retain zero measurements; reimplementations do not witness them.

Completion evidence

All arms need precision/recall, binding and location errors, parse failures, latency/throughput, CPU/RSS, bytes, rule setup/operator time, and total cost, with pinned versions/rules and independent output read-back.

TestCompareLocalKeepsStructuralSearchAlternativesExplicit locks the inventory, native oracle, baseline failure, and zero rows. BenchmarkSearchRepeatedMetavariable runs the real parser/unifier and verifies bindings each iteration. Local timing is not a cross-product claim; no tool is ranked until #6182 has real runs.