No, I said make the flag safe, not misremember the rules for parenthesis in regular expressions

Author: gwynne

.github/workflows/run-unit-tests.yml

@@ -181,7 +181,7 @@ jobs:
       - name: Strip flags incompatible with 6.0
         if: ${{ matrix.swift-config.image == 'swift:6.0-noble' && steps.swift-check.outputs.swift-compatible == 'true' && (matrix.swift-config.build-mode == 'debug' || inputs.with_release_mode_testing) }}
         shell: bash
-        run: 'echo "EXTRA_FLAGS=$(echo "${EXTRA_FLAGS}" | sed -Ee "s/--((dis|en)able-experimental-prebuilts)|(enable-all-traits)//g")" >>"${GITHUB_ENV}"'
+        run: 'echo "EXTRA_FLAGS=$(echo "${EXTRA_FLAGS}" | sed -Ee "s/--(((dis|en)able-experimental-prebuilts)|enable-all-traits)//g")" >>"${GITHUB_ENV}"'
       - name: Restore .build
         # If cache-restore is causing the CI to fail, use 'Enable debug logging' on a re-run to disable the step.
         if: ${{ runner.debug != '1' && steps.swift-check.outputs.swift-compatible == 'true' && (matrix.swift-config.build-mode == 'debug' || inputs.with_release_mode_testing) }}