ci(all-green): drop the cross-run lcov merge for Datadog coverage uploads

datadog-ci coverage upload recursively discovers every report file under a
given path by default, so uploading each sibling workflow's already
per-run-merged lcov file directly (one datadog-ci invocation over
coverage-upload/) makes the extra merge into a single final lcov file
redundant, mirroring the same simplification already applied to junit
uploads.

Generated by Claude Code.

Author: rochdev

scripts/group-coverage.mjs

@@ -31,7 +31,6 @@ import istanbulLibCoverage from 'istanbul-lib-coverage'
 
 const INPUT_DIR = 'coverage-results'
 const OUTPUT_DIR = 'coverage-upload'
-const FINAL_OUTPUT_DIR = 'coverage-upload-final'
 const ARTIFACT_PREFIX = 'coverage-'
 
 const REPORTS = new Map([
@@ -283,50 +282,4 @@ function mergeRunCoverage (runId, inputDir = INPUT_DIR, outputDir = OUTPUT_DIR)
   return { lcovDir, jsonDir }
 }
 
-/**
- * Recursively collect every already-per-run-merged `lcov.info` file under `coverage-upload/<run-id>/lcov/`.
- *
- * @param {string} dir
- * @param {string[]} out
- * @returns {string[]}
- */
-function collectMergedLcovFiles (dir, out = []) {
-  let entries
-  try {
-    entries = readdirSync(dir, { withFileTypes: true })
-  } catch {
-    return out
-  }
-  for (const entry of entries) {
-    const full = join(dir, entry.name)
-    if (entry.isDirectory()) {
-      collectMergedLcovFiles(full, out)
-    } else if (entry.name === 'lcov.info') {
-      out.push(full)
-    }
-  }
-  return out
-}
-
-/**
- * Merge every sibling workflow's already-per-run-merged lcov file into one final lcov file, for a
- * single Datadog coverage upload covering the whole commit instead of one upload per workflow run.
- * Unlike Codecov, whose per-workflow flag keeps its upload scoped to one run at a time (see
- * `upload-coverage.mjs`), Datadog's coverage flag is the same for every run, so there's no reason
- * to pay for a separate upload call per workflow.
- *
- * @param {string} [inputDir]
- * @param {string} [outputDir]
- * @returns {string|null} Directory containing the merged `lcov.info`, or null if no run produced one.
- */
-function mergeAllRunsCoverage (inputDir = OUTPUT_DIR, outputDir = FINAL_OUTPUT_DIR) {
-  const reportPaths = collectMergedLcovFiles(inputDir)
-  if (reportPaths.length === 0) return null
-
-  const lcovDir = join(outputDir, 'lcov')
-  mkdirSync(lcovDir, { recursive: true })
-  writeFileSync(join(lcovDir, 'lcov.info'), mergeLcov(reportPaths))
-  return lcovDir
-}
-
-export { mergeAllRunsCoverage, mergeCoverageJson, mergeLcov, mergeRunCoverage, planCoverageGroups }
+export { OUTPUT_DIR, mergeCoverageJson, mergeLcov, mergeRunCoverage, planCoverageGroups }

scripts/group-coverage.spec.mjs

@@ -5,9 +5,7 @@ import { join } from 'node:path'
 
 import { afterEach, beforeEach, describe, it } from 'mocha'
 
-import {
-  mergeAllRunsCoverage, mergeCoverageJson, mergeLcov, mergeRunCoverage, planCoverageGroups,
-} from './group-coverage.mjs'
+import { mergeCoverageJson, mergeLcov, mergeRunCoverage, planCoverageGroups } from './group-coverage.mjs'
 
 /**
  * One cell's discovered report set: one `lcov` entry per Node.js version the cell ran.
@@ -233,39 +231,4 @@ describe('group-coverage', () => {
       assert.equal(existsSync(join(dir, 'coverage-upload', '42')), false)
     })
   })
-
-  describe('mergeAllRunsCoverage', () => {
-    let dir
-
-    beforeEach(() => {
-      dir = mkdtempSync(join(tmpdir(), 'group-coverage-all-runs-'))
-    })
-
-    afterEach(() => {
-      rmSync(dir, { force: true, recursive: true })
-    })
-
-    it('sums DA hit counts across every run\'s already-merged lcov file', () => {
-      const input = join(dir, 'coverage-upload')
-      const output = join(dir, 'coverage-upload-final')
-      mkdirSync(join(input, '1', 'lcov'), { recursive: true })
-      mkdirSync(join(input, '2', 'lcov'), { recursive: true })
-      writeFileSync(join(input, '1', 'lcov', 'lcov.info'), 'SF:shared.js\nDA:1,1\nLF:1\nLH:1\nend_of_record\n')
-      writeFileSync(join(input, '2', 'lcov', 'lcov.info'), 'SF:shared.js\nDA:1,2\nLF:1\nLH:1\nend_of_record\n')
-
-      const lcovDir = mergeAllRunsCoverage(input, output)
-
-      assert.equal(lcovDir, join(output, 'lcov'))
-      assert.equal(
-        readFileSync(join(lcovDir, 'lcov.info'), 'utf8'),
-        'SF:shared.js\nDA:1,3\nLF:1\nLH:1\nend_of_record\n'
-      )
-    })
-
-    it('returns null when no run produced an lcov file', () => {
-      const input = join(dir, 'coverage-upload')
-      mkdirSync(input, { recursive: true })
-      assert.equal(mergeAllRunsCoverage(input, join(dir, 'coverage-upload-final')), null)
-    })
-  })
 })

scripts/upload-coverage.mjs

@@ -1,4 +1,5 @@
-import { mergeAllRunsCoverage, mergeRunCoverage } from './group-coverage.mjs'
+import { existsSync } from 'node:fs'
+import { OUTPUT_DIR, mergeRunCoverage } from './group-coverage.mjs'
 import { logUploads, runUpload, runUploadWithRetry } from './run-upload.mjs'
 
 // Codecov validates flags against `^[\w\.\-]{1,45}$` and silently drops any that fail.
@@ -108,18 +109,19 @@ export async function uploadCoverage (run, options) {
 }
 
 /**
- * Merge every sibling workflow's already-per-run-merged lcov file into one and upload it to Datadog
- * in a single call, instead of uploading each workflow run's coverage separately — Datadog's
- * coverage flag doesn't vary per run, so nothing needs the per-run separation Codecov's flags
- * require (see `uploadCoverage`).
+ * Upload every sibling workflow's already-per-run-merged lcov file to Datadog in a single call,
+ * instead of uploading each workflow run's coverage separately — Datadog's coverage flag doesn't
+ * vary per run, so nothing needs the per-run separation Codecov's flags require (see
+ * `uploadCoverage`). `datadog-ci coverage upload` recursively discovers every report file under a
+ * given path by default, so there's no need to merge every run's lcov file into one document first,
+ * the way junit upload used to (see `upload-junit.mjs`).
  *
  * @returns {Promise<import('./run-upload.mjs').UploadResult[]>}
  */
 export async function uploadAllCoverageToDatadog () {
-  const lcovDir = mergeAllRunsCoverage()
-  if (!lcovDir) return []
+  if (!existsSync(OUTPUT_DIR)) return []
 
-  const result = await runUpload('datadog-ci', ['coverage', 'upload', lcovDir, '--flags', 'coverage'])
+  const result = await runUpload('datadog-ci', ['coverage', 'upload', OUTPUT_DIR, '--flags', 'coverage'])
   return [result]
 }