fix(v8): catch boundary lines

[wellwelwel]

This step completes @pokujs/coverage against Node.js ✨

Steps

• 🐢 Node.js (easy)
  • TypeScript (medium)
• 🦕 Deno (medium)
  • TypeScript (complex)
• 🍞 Bun (Why?) ;-;
  • TypeScript (same)

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/v8-audit results for Node.js ✨

Poku codebase vs. @pokujs/coverage, @pokujs/c8, and @pokujs/monocart.

Generated: 2026-04-26 against the captured run at coverage/v8/ (1070 V8 dumps).
Scope: Node.js coverage fidelity only. Bun (JSC) and Deno are out of scope here.
Method: every uncovered entry in each reporter's lcov.info is cross-checked against the raw V8 dumps using the v8-audit skill from pokujs/coverage. Verdicts are faithful (V8 confirms count = 0) or suspect (V8 says count > 0 somewhere covering the position, indicating a pipeline bug).

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Headline counts

Reporter	Uncovered entries	Faithful	Suspect	Suspect ratio
@pokujs/coverage	315	315	0	0.0%
@pokujs/monocart	40	15	25	62.5%
@pokujs/c8	1149	478	671	58.4%

Each reporter consumed the same Poku run via plugin teardown. Differences in entry counts and verdicts are entirely about how each reporter post-processes V8 dumps.

The headline numbers above conflate two distinct entry kinds. The breakdown below tells the actual story:

Reporter	Line suspects	Function suspects	Branch suspects	Notes
@pokujs/coverage	0	0	0	All 184 lines, 7 functions, 124 branches faithful.
@pokujs/monocart	14	0	11	The 14 line suspects are real pipeline issues.
@pokujs/c8	228	100	343	Plus 18 esbuild-wrapper FN ghosts (counted as suspect).

Caveat on branch suspects: my auditor probes branches at line resolution, not arm resolution. A line whose nearest enveloping V8 range has count > 0 is flagged as suspect for every uncovered arm on that line, even when the specific arm genuinely never executed. Branch suspects across all three reporters are inflated by this. Line and function suspects are the trustworthy axis.

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Suspect findings: @pokujs/c8

Esbuild-wrapper functions (18 entries)

c8 emits tsx-injected CJS wrappers as named functions at line 1 of every .ts source: __name, __copyProps, __toCommonJS, __toESM, get. These positions don't exist in source. Worse, c8 frequently emits duplicate FN/FNDA pairs for the same wrapper in the same file, one with the real count and one stale with FNDA:0. Examples:

• src/parsers/get-runtime.ts: emits FNDA:0,getRuntime AND FNDA:1,getRuntime (duplicate, while coverage and monocart emit only one entry).
• src/builders/assert.ts: emits FN:107,doesNotThrow (count 0) AND FN:107,doesNotThrow (count 28).

These are pipeline artifacts, not code that needs tests.

Real line/function suspects (310 entries, top files)

File	Line+function suspects
src/builders/assert.ts	80
src/modules/helpers/describe.ts	60
src/bin/index.ts	52
src/services/reporters/poku.ts	41
src/modules/helpers/modifiers.ts	32
src/modules/helpers/it/core.ts	30
src/services/format.ts	28
src/services/run-test-file.ts	23
src/modules/essentials/poku.ts	21

Pattern: c8 reports whole blocks of executed code as DA:N,0 when the surrounding V8 ranges show clear hits. Spot-check on src/builders/assert.ts:107–139: V8 reports count > 0 on every line, coverage and monocart agree, and c8 reports DA:107,0...DA:139,0. This is c8 attributing source-mapped offsets to the wrong V8 range, losing entire function bodies in the report.

c8 also produces the structurally most divergent reports: e.g. bin/index.ts shows FNH:0 (no functions hit) despite all five real functions clearly executing.

c8 verdict: not faithful to V8. 310 real-line-or-function suspects + 18 wrapper ghosts on the Poku codebase. Recommend not relying on c8 for measuring Poku's Node.js coverage.

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Suspect findings: @pokujs/monocart

File	Line+function suspects	Detail
src/parsers/get-runtime.ts	6	L5/L6/L7 reported DA:N,0, but V8 says hit=1 on all three (single-process branches).
src/parsers/get-runner.ts	4	L9/L35 reported DA:N,0, but V8 says hit=114 / hit=212.
src/services/watch.ts	4	L21/L44 reported as 0, but V8 says hit=3.
src/services/pid.ts	2	L26/L61 anonymous arrows reported as 0, but V8 says hit=206 (every process).
src/modules/plugins.ts	2	L29 } catch { reported as 0, but V8 says hit=37.
src/modules/helpers/kill.ts	2	L13 ternary cond reported as 0, but V8 says hit=2.
src/services/run-test-file.ts	2	L62 reported as 0, but V8 says hit=85.
src/modules/helpers/create-service.ts	3	L143/L186 reported as 0, but V8 says hit=14 / hit=65.

Pattern: monocart drops hits on lines that V8 marks executed in every loaded process (e.g. pid.ts:26: V8 reports hit=206/206, monocart reports DA:26,0). This is a hard pipeline bug: monocart's V8-to-source-map remap is producing zero-counts on positions where V8 unambiguously says > 0.

Notable: parsers/get-runtime.ts:5–7 is the canonical case, with three single-process conditionals, each hit=1 in V8, all reported 0 by monocart. Coverage reports them correctly.

monocart verdict: not faithful to V8 on Poku. 14 real-line + 11 branch-line suspects on a 40-entry sample. The reporter under-counts execution on every file with conditional flow control.

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Findings: @pokujs/coverage

0 suspects. All 315 uncovered entries are confirmed faithful to V8: 184 lines, 7 functions, 124 branches.

Edge case retained as faithful: src/modules/helpers/kill.ts:13 (isWindows)

L12 PIDs.map(async (p) => {                   # V8 hit=2  lcov hit=2  ✅
L13 isWindows                                 # V8 hit=2  lcov hit=0  (faithful via SKILL caveat)
L14 ? await killPIDService.windows(p)         # V8 hit=0  lcov hit=0  ✅
L15 : await killPIDService.unix(p);           # V8 hit=0  lcov hit=0  ✅
L16 })                                        # V8 hit=2  lcov hit=2  ✅

V8 emits no sub-range that isolates L13 from L14/L15. The only enveloping range is the outer arrow callback. Per the SKILL caveat ("treat as uncovered legitimately when the surrounding context also lacks hits in the same code block"), L13 is faithful: Istanbul attributes the ternary condition to the bodies that follow, all of which are correctly zero.

Branches (124) and functions (7)

• All 7 FNDA:0 functions are declarations whose body never executed (callbacks stored but not invoked, SIGINT handlers not triggered, kill arrow defined but unused). Istanbul convention treats FNDA:0 as the correct label for these.
• All 124 uncovered branch arms correspond to V8 sub-ranges with count = 0, or to lines where the entire line has hit = 0. Spot-checks on bin/index.ts:14 (--version flag never passed), parsers/get-runtime.ts:5–7 (single-process conditional arms), polyfills/jsonc.ts:49–50 (line-comment path unused) all confirm V8 agreement at the arm level.

coverage verdict: faithful to V8.

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Structural divergences (not bugs)

These are reporting-shape differences, not faithfulness issues:

• LF (lines found) accounting:

  • coverage: source-mapped per-statement count after V8-to-Istanbul remap. bin/index.ts reports LF:196 against a 260-line source (executable lines only).
  • monocart: counts only function-declaration lines, ignoring statements. bin/help.ts reports LF:9 against a 99-line source.
  • c8: reports LF:260 matching the source line count, but treats blank lines and comments as executable (over-counts).

• FN (functions) accounting:

  • coverage: emits real source functions. bin/help.ts → FNF:4.
  • monocart: emits one FN per arrow expression (including IIFEs and array-method callbacks). bin/help.ts → FNF:9.
  • c8: emits source functions plus tsx esbuild wrappers (__name, __copyProps, etc.) often duplicated. bin/help.ts → FNF:6 with five wrappers.

• Anonymous-function naming:

  • coverage: (anonymous_N) numbered relative to the source.
  • monocart: (anonymous_N) plus mangled paths like Object.assign.ok.ok, import_each.each.before.cb.
  • c8: same as monocart but adds duplicates.

These differences explain why aggregate percentages diverge across reporters even when all three agree on what was executed.

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Final verdict

Reporter	Faithful to V8?	Conditions
@pokujs/coverage	Yes	0 pipeline bugs across 315 audited entries (184 lines, 7 functions, 124 branches).
@pokujs/monocart	No	14 real line suspects + 11 branch suspects on a 40-entry sample. Drops hits on lines V8 unambiguously confirms executed (e.g. get-runtime.ts:5–7, pid.ts:26, pid.ts:61).
@pokujs/c8	No	310 real line/function suspects + 18 esbuild-wrapper FN ghosts + duplicate FN entries. Loses entire function bodies in the report (e.g. builders/assert.ts:107–139). Structurally divergent (FNH:0 for bin/index.ts).

Bottom line: @pokujs/coverage is the only one of the three Node.js reporters that produces an LCOV faithful to the raw V8 evidence on the Poku codebase.