Stop the sdist guard from failing on a complete sdist

.github/workflows/release.yml

@@ -36,11 +36,15 @@ jobs:
         # never build. Fail the release rather than publish that again.
         run: |
           set -euo pipefail
+          # Listed once into a file rather than piped per-file: `tar | grep -q`
+          # makes grep exit on its first match, tar dies of SIGPIPE, and
+          # pipefail then reports the whole check as a failure.
+          tar tzf dist/*.tar.gz > "$RUNNER_TEMP/sdist-listing.txt"
           for f in CMakeLists.txt src/cuda/knn.cu src/cuda/lof.cu \
                    src/cuda/pipeline.cu src/cuda/preprocess.cu \
                    src/cuda/binding.cpp include/culof.h \
                    include/culof_internal.cuh src/culof/__init__.py; do
-            tar tzf dist/*.tar.gz | grep -q "/$f$" \
+            grep -q "/$f$" "$RUNNER_TEMP/sdist-listing.txt" \
               || { echo "::error::sdist is missing $f"; exit 1; }
           done
           echo "sdist contains every file needed to build"