feat(test): accept space/comma/newline separated --changed-files (CI paths-filter)

Author: sbryngelson

.github/workflows/test.yml

@@ -53,6 +53,7 @@ jobs:
     runs-on: 'ubuntu-latest'
     outputs:
       checkall: ${{ steps.changes.outputs.checkall }}
+      changed_files: ${{ steps.changes.outputs.checkall_files }}
     steps:
       - name: Clone
         uses: actions/checkout@v4
@@ -62,6 +63,7 @@ jobs:
         id: changes
         with:
           filters: ".github/file-filter.yml"
+          list-files: shell
 
   github:
     name: ${{ matrix.nvhpc && format('NVHPC {0} ({1})', matrix.nvhpc, matrix.target) || format('Github ({0}, {1}, {2}, {3})', matrix.os, matrix.mpi, matrix.debug, matrix.intel && 'intel' || 'GNU') }}
@@ -262,11 +264,17 @@ jobs:
       - name: Test
         if:   '!matrix.nvhpc'
         run:  |
-          /bin/bash mfc.sh test -v --max-attempts 3 -j $(nproc) $TEST_ALL $TEST_PCT $PRECISION
+          # Coverage-based test selection in SHADOW mode on PRs: the selector
+          # prints what it WOULD run, but the full suite still runs (no
+          # --select-enforce). Enforcement is a separate, later change.
+          SELECT=""
+          [ "${{ github.event_name }}" = "pull_request" ] && SELECT="--only-changes"
+          /bin/bash mfc.sh test -v --max-attempts 3 -j $(nproc) $SELECT --changed-files "$CHANGED_FILES" $TEST_ALL $TEST_PCT $PRECISION
         env:
           TEST_ALL: ${{ matrix.mpi == 'mpi' && '--test-all' || '' }}
           TEST_PCT: ${{ matrix.debug == 'reldebug' && '-% 20' || '' }}
           PRECISION: ${{ matrix.precision != '' && format('--{0}', matrix.precision) || '' }}
+          CHANGED_FILES: ${{ needs.file-changes.outputs.changed_files }}
 
       # ── NVHPC build + test (via docker exec into long-lived container) ──
       - name: Build (NVHPC)

tests/coverage_map.json.gz

@@ -133,11 +133,12 @@ def _merge_base(cwd, branch):
 def get_changed_files(root_dir, compare_branch="master", explicit: Optional[str] = None):
     """Set of changed repo-relative paths, or None if undeterminable (-> run all).
 
-    `explicit` is a newline-separated list from CI (paths-filter); preferred when given.
+    `explicit` is a changed-file list from CI (paths-filter); preferred when given. It may
+    be separated by newlines, spaces, or commas (paths-filter's shell output is space-sep).
     Otherwise use git merge-base, self-healing a shallow clone with a deepen+retry.
     """
     if explicit is not None:
-        return {f for f in explicit.splitlines() if f.strip()}
+        return {f for f in explicit.replace(",", " ").split() if f.strip()}
     try:
         base = _merge_base(root_dir, compare_branch)
         if base is None:

toolchain/mfc/test/coverage.py

@@ -254,3 +254,10 @@ def test_rung5_empty_coverage_is_included():
     run, skip, _ = select_tests(cases, cov_map, {"src/simulation/m_rhs.fpp"})
     run_keys = {c.coverage_key() for c in run}
     assert "hasempty" in run_keys and skip == []
+
+
+def test_changed_files_explicit_space_and_comma_separated():
+    from mfc.test.coverage import get_changed_files
+
+    assert get_changed_files("/r", "master", explicit="src/a.fpp src/b.fpp") == {"src/a.fpp", "src/b.fpp"}
+    assert get_changed_files("/r", "master", explicit="src/a.fpp,src/b.fpp") == {"src/a.fpp", "src/b.fpp"}