[sergo] Sergo Report: Registry-35 nolint+filecheck Parity Sweep - 2026-06-27

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Overview

Run R49 (49th Sergo run). Linter registry is stable at 35 analyzers (grep -c Analyzer cmd/linters/main.go = 35; no 36th since R48). Serena LSP toolset unchanged at 23 tools. This run's new-exploration half was a full internal/nolint + internal/filecheck suppression/test-skip parity sweep across all 35 analyzers — a dimension never audited end-to-end before. The cached half reconciled the R46/R47 nolint-parity issues and found two of them have landed in code while their issues remain open.

Key metrics

Metric	Value
Registry	35 analyzers (stable)
Serena LSP tools	23 (stable, no change)
nolint-wired linters	29 / 35
Findings this run	6
Issues created	2 (#41844, #41845)
Duplicates skipped	4 (already in #40243 / #40435)
Success score	9 / 10

Tool & registry updates

No Serena tool changes (23 stable since R4). No new linter (35 stable since R48). pkg/linters/doc.go still reads "30 active analyzers" — the long-standing doc drift tracked by #40436 persists.

Strategy split (50 / 50)

Cached component — reconcile + sibling-asymmetry probe. Re-checked the standing nolint-parity issues against current code. Found that #41377 (4 context-family linters) and #40734 (the two threshold linters) have already had internal/nolint wired in — contextcancelnotdeferred, ctxbackground, execcommandwithoutcontext, timesleepnocontext, largefunc, and excessivefuncparams all now honour //nolint:. The issues are still open (landed-but-open), a recurring pattern for this team.

New-exploration component — full parity matrix. Swept every analyzer for internal/nolint and internal/filecheck wiring and cross-checked type-resolution quality. This surfaced the remaining nolint-missing cluster and a coarse verb-presence check in a CI-enforced linter.

Findings

1. nolint-suppression parity gap — 5 linters (→ #41844)

Five analyzers emit diagnostics but import no internal/nolint: fileclosenotdeferred, ossetenvlibrary, sprintferrorsnew, sprintferrdot, lenstringzero. The strongest cases are sibling asymmetries:

• fileclosenotdeferred (no nolint) vs its near-twin contextcancelnotdeferred (nolint at :32/:63/:96).
• ossetenvlibrary (no nolint) vs its policy-twin osexitinlibrary (nolint at :37/:61).

Several of these report judgment-call diagnostics (manual Close() before a rename; os.Setenv in a support file) that are sometimes legitimately correct, so an unsuppressable report blocks valid code and prevents CI enforcement — the exact blocker that motivated the now-landed #41377/#40734. (ssljson also lacks nolint but is a spec-domain validator, excluded intentionally.)

2. fmterrorfnoverbs — escaped %% false negative (→ #41845)

fmterrorfnoverbs.go:63 decides verb-presence with strings.Contains(val, "%") on the raw literal. An escaped literal percent %% contains % but is not a verb, so fmt.Errorf("90%% done") (no real verb) is wrongly skipped — a false negative in a CI-enforced linter. Fix: strip %% pairs before testing, reusing the %%-aware scan referenced by #40434 / #38788. The rest of the linter (IsFmtErrorf type-resolution, nolint) is correct.

Audited-clean & duplicates skipped

• Clean: strconvparseignorederror (type-resolved PkgName.Path()=="strconv" + nolint), sprintferrorsnew / ossetenvlibrary package-identity (type-resolved), fmterrorfnoverbs apart from the %% gap.
• Duplicates skipped (already open): fprintlnsprintf:144 (ident.Name=="fmt"), osexitinlibrary:59, fileclosenotdeferred:172, contextcancelnotdeferred:138 — all syntactic package-by-name matches already covered by Linter precision: migrate the 3 remaining CI-enforced linters that match stdlib packages by identifier name to astutil.IsPkgSele [Content truncated due to length] #40243 and Linter precision: two newest linters (fileclosenotdeferred, contextcancelnotdeferred) match stdlib packages by identifier name — [Content truncated due to length] #40435.
• Lower-value note: strconvparseignorederror and jsonmarshalignoredeerror lack filecheck.IsTestFile (lint test files), but both are CI-enforced with -test=false, mooting it in CI.

Generated tasks

1. Wire internal/nolint into the 5-linter cluster (#41844) — mechanical, ~5–8 lines + one testdata case each, mirroring the landed nolint parity gap: 4 non-enforced context-family linters have no internal/nolint suppression (execcommandwithoutcontext, ctxback [Content truncated due to length] #41377 template. Effort: low.
2. %%-aware verb scan in fmterrorfnoverbs (#41845) — single-function change + testdata. Effort: low.

Historical context

48 prior runs, 347 cumulative findings, 97 tasks, avg success 8.8. The nolint-parity theme has been productive: #aw_sg44a2 (threshold linters), #41377 (context family) — both now landed in code. R49 completes the sweep by enumerating the remaining gap.

Recommendations & next-run focus (R50)

• Recheck R49 landings plus the open landed-but-open set (nolint parity gap: 4 non-enforced context-family linters have no internal/nolint suppression (execcommandwithoutcontext, ctxback [Content truncated due to length] #41377, Threshold linters: excessivefuncparams lints test files (every sibling FuncDecl linter skips them); largefunc & excessivefuncpar [Content truncated due to length] #40734, panicinlibrarycode: init() and documented-contract exemptions cross FuncLit boundaries — false negatives for panics in nested cl [Content truncated due to length] #41606, wgdonenotdeferred precision: non-deferred wg.Done() inside a goroutine launched in a loop escapes detection (FuncLit scope bound [Content truncated due to length] #40947).
• Watch the nolint-missing set shrink as nolint-suppression parity gap: 5 linters still have no (nolint/redacted) support, blocking CI enforcement #41844 is addressed.
• Registry watch: detect a 36th analyzer via grep -c Analyzer vs 35 and the doc-omitted-minus-known heuristic.
• Fresh probes remaining: seenmapbool internals (seenmapbool: duplicate diagnostics for set-maps declared inside function literals (double AST traversal) #40733 double-report), errstringmatch coverage (errstringmatch coverage gap: only strings.Contains(err.Error(), ...) is flagged — HasPrefix/HasSuffix/EqualFold/Index on err.Err [Content truncated due to length] #40244), hardcodedfilepath recheck.

References:

• §28279225452
• Reconciled landed-but-open: nolint parity gap: 4 non-enforced context-family linters have no internal/nolint suppression (execcommandwithoutcontext, ctxback [Content truncated due to length] #41377, Threshold linters: excessivefuncparams lints test files (every sibling FuncDecl linter skips them); largefunc & excessivefuncpar [Content truncated due to length] #40734
• Duplicate coverage: Linter precision: migrate the 3 remaining CI-enforced linters that match stdlib packages by identifier name to astutil.IsPkgSele [Content truncated due to length] #40243, Linter precision: two newest linters (fileclosenotdeferred, contextcancelnotdeferred) match stdlib packages by identifier name — [Content truncated due to length] #40435

Generated by 🤖 Sergo - Serena Go Expert · 231.1 AIC · ⌖ 14.3 AIC · ⊞ 5.9K · ◷

• expires on Jun 27, 2026, 9:09 PM UTC-08:00

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