[sergo] Sergo Report: STABLE-84 Reconcile + ParenExpr Equality Gap - 2026-10-24

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Executive Summary

• Serena: 24 tools stable, gopls ready (verified via get_current_config before any analysis, per the R102 lesson).
• Registry: stable at 84 linters, no new linter since commit cc19f14 (Add formatintitoa and osisnotexist Go linters #70801).
• Reconcile: 2 open sergo issues re-read in full and reconfirmed 100% accurate, zero reverse-phantom flips.
• New finding: mapdeletecheck equality helper has an asymmetric-ParenExpr gap, filed as 1 new issue.
• 2 verification sweeps came back clean/confirmed-fixed: CI LINTER_FLAGS native-vs-wasm diff, and a previously-flagged Close() handler duplication.

Tool Update

No Serena tool-list changes (24/24 stable). Language server status: ready, checked first this run.

Strategy Split (50/50)

• Cached reuse (50%): periodic ci_target_asymmetry diff of cgo.yml native (line 1668) vs wasm (line 1695) LINTER_FLAGS strings; reverse-phantom re-verification of the 2 open issues; reverse-phantom re-verification of the R97 Close()-duplication fix.
• New exploration (50%): repo-wide search for sameExpr-shaped equality helpers surfaced one never-audited instance in mapdeletecheck with a distinct ParenExpr-handling bug.

Findings

mapdeletecheck: asymmetric ParenExpr wrapping escapes detection (filed)

pkg/linters/mapdeletecheck/mapdeletecheck.go sameExpr (lines 169-202) requires both sides of a comparison to already be a ParenExpr node before recursing into them, with no upfront UnwrapParenExpr call. This differs from the already-fixed reference pattern in uncheckedsliceindex.go (366-368), which unwraps both operands first. As a result, a parenthesized map key on only one side of the pattern (for example the if-condition key wrapped in parens but the delete() call argument not wrapped) silently escapes this CI-enforced, autofix-capable linter. Zero testdata coverage for any ParenExpr shape exists today. Filed with a concrete before/after recommendation and a validation checklist.

Verification sweeps (no new issue)

• cgo.yml native and wasm LINTER_FLAGS strings are byte-identical apart from the GOOS/GOARCH prefix and package subset - no new ci_target_asymmetry instance found.
• The Close()-family duplication flagged at R97 (deferrerrorunchecked vs unchecked_deferredclose both flagging a bare deferred Close() call) is now resolved: deferredSignature carves out zero-argument Close() calls so only one linter reports them.
• Both previously-open issues (osisnotexist idiom-reflag-no-allowlist, wgdonenotdeferred paren-unwrap-gap) were re-read in full and remain 100% accurate against current code.

Generated Tasks

1. Fix mapdeletecheck sameExpr to unwrap ParenExpr unconditionally on each operand before comparing (mirroring the uncheckedsliceindex.go reference pattern), and add 2 regression testdata cases covering asymmetric parenthesization on each side. Effort: low.

Issues Created

• 1 new issue: mapdeletecheck ParenExpr equality gap.
• 0 duplicates skipped - no existing open issue covers this exact shape.

Metrics

• Total Sergo runs: 106
• Cumulative findings: 595
• Cumulative tasks: 178
• Average success score: 8.66
• This run score: 8/10 - one well-evidenced, non-duplicate finding; verification sweeps consumed the remaining budget without surfacing additional filable bugs.

Historical Context

This is the third consecutive run with a stable 84-linter registry. The standing day-one probes (paren_unwrap_gap, ci_target_asymmetry, idiom_reflag_no_allowlist, node_filter_too_narrow) are now waiting on either an 85th linter or a fresh shared-helper shape to probe. A repo-wide grep for the sameExpr(pass, x, y ast.Expr) bool signature found exactly 2 implementations; both are now solo-audited.

Next-Run Focus

• Watch for the 85th linter via the registry.go commit detector.
• If no new linter appears, grep for other shared equality or state-tracking helper shapes not yet covered by an existing pattern class, rather than re-probing exhausted veins.

References:

• §40059799133

Generated by 🤖 Sergo - Serena Go Expert · claude · agent · ~174 AIC · ⌖ ~1 AIC · ⊞ 5.4K · ◷

• expires on Oct 24, 2026, 8:00 PM UTC-08:00

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This discussion was automatically closed because it expired on 2026-10-25T04:00:04.084Z.

Closed by Workflow