fix: an absent report is not a coverage bug — with the test #83 was closed for lacking

.github/workflows/action-degrades.yml

@@ -0,0 +1,73 @@
+name: upload-coverage degrades on an absent report
+
+# THE TEST #83 DID NOT HAVE, and the reason it was closed:
+#
+#   "This repository is public, so its storage is free and its own CI cannot reach the
+#    absent-artifact state by accident — it has to be constructed."
+#
+# So it is constructed here. `upload-coverage` is asked for an artifact that cannot exist, and the
+# job must come back GREEN with the absence annotated. An absent report is not a coverage bug:
+# coverage is a REPORT, `Every unit ran, exactly once` is a CORRECTNESS CLAIM, and only the second
+# should be able to fail a suite.
+#
+# Without this, the degrade path ships untested and is exercised for the first time on a private
+# consumer whose org has run out of Actions storage — which is exactly where it was needed and
+# exactly where nobody can watch it.
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  absent:
+    name: an artifact that cannot exist
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v7
+
+      # No artifact of this name is produced by any job in this run, so the download finds nothing.
+      # `name:` would hard-fail here; `pattern:` is what makes the difference the action now relies
+      # on, and this step is what keeps that true.
+      - id: run
+        uses: ./actions/upload-coverage
+        with:
+          artifact: no-such-artifact-${{ github.run_id }}
+          codecov-token: ''
+
+      - name: the job survived, and said why
+        run: |
+          set -euo pipefail
+          echo "reached the step after upload-coverage — the action did not abort the job"
+
+  present:
+    name: a report that does exist still uploads-or-degrades cleanly
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v7
+
+      # THE POSITIVE CONTROL. Without it, an action that did nothing at all would pass the job
+      # above, and "degrades on absence" would be indistinguishable from "never works".
+      - name: Build a real lcov and publish it
+        run: |
+          set -euo pipefail
+          printf 'SF:src/Fake.jl\nDA:1,1\nDA:2,0\nend_of_record\n' > lcov.info
+          grep -c '^SF:' lcov.info
+
+      - uses: actions/upload-artifact@v7
+        with:
+          name: degrade-probe-lcov
+          path: lcov.info
+          retention-days: 1
+
+      - uses: ./actions/upload-coverage
+        with:
+          artifact: degrade-probe-lcov
+          codecov-token: ''
+
+      - name: it found the report
+        run: echo "the present-report path ran to completion"

Project.toml

@@ -1,6 +1,6 @@
 name = "TestShards"
 uuid = "acceef1d-f5e0-4fe4-a546-818dc56ce7b2"
-version = "0.3.38"
+version = "0.3.39"
 authors = ["sota shimozono <shimozono-sota631@g.ecc.u-tokyo.ac.jp>"]
 
 [deps]

actions/upload-coverage/action.yml

@@ -116,18 +116,39 @@ runs:
       with:
         submodules: ${{ inputs.submodules }}
 
+    # BY PATTERN, NOT BY NAME, and the difference is the whole fix. `download-artifact` by `name:`
+    # HARD-FAILS when the artifact is absent; by `pattern:` it succeeds with zero results. That
+    # asymmetry is why `collect` reaches its completeness gate under a full artifact quota while
+    # this job used to die at step two — same missing artifact, two different outcomes.
+    #
+    # An absent report is not a coverage BUG. Coverage is a report; "every unit ran exactly once" is
+    # a correctness claim, and only the second should be able to fail a suite. A private consumer
+    # whose org has run out of Actions storage was getting a red required check for a run whose
+    # tests were all green — for days, because storage is accrued in GigabyteHours and does not fall
+    # when artifacts are deleted, so it does not recover until the billing period rolls over.
     - uses: actions/download-artifact@v8
+      id: fetch
       with:
-        name: ${{ inputs.artifact }}
+        pattern: ${{ inputs.artifact }}
+        merge-multiple: true
 
-    - shell: bash
+    - id: report
+      shell: bash
       run: |
         set -euo pipefail
-        [ -s lcov.info ] || { echo "::error::${{ inputs.artifact }} contained no lcov.info — did the sharded run finish with coverage on?"; exit 1; }
+        if [ ! -s lcov.info ]; then
+          # LOUD, and not fatal. The absence is annotated and summarised; what it must not do is
+          # gate a suite on a report.
+          echo "::warning::no ${{ inputs.artifact }} to upload — the sharded run produced no merged report. Coverage is NOT being sent; the tests themselves are unaffected."
+          echo "Coverage **not uploaded**: no \`${{ inputs.artifact }}\` artifact. Under a full Actions storage quota this is expected and says nothing about the tests." >> "$GITHUB_STEP_SUMMARY"
+          echo "have=false" >> "$GITHUB_OUTPUT"
+          exit 0
+        fi
         echo "Merged report: $(grep -c '^SF:' lcov.info) source files."
+        echo "have=true" >> "$GITHUB_OUTPUT"
 
     - uses: codecov/codecov-action@v7
-      if: ${{ steps.token.outputs.have == 'true' }}
+      if: ${{ steps.token.outputs.have == 'true' && steps.report.outputs.have == 'true' }}
       continue-on-error: ${{ inputs.fail-on-error != 'true' }}
       with:
         files: lcov.info