Update GitHub Actions cache even if build/test fails.

.github/workflows/build.yml

@@ -43,13 +43,17 @@ jobs:
         run: bazel test --test_output=errors //...
 
       - name: Save end time
+        # Always save the end time so we can calculate the build duration.
+        if: always()
         uses: josStorer/get-current-time@v2
         id: end-time
         with:
           # Unix timestamp -- seconds since 1970.
           format: X
 
       - name: Calculate build duration
+        # Always calculate the build duration so we can update the cache if needed.
+        if: always()
         run: |
           START=${{ steps.start-time.outputs.formattedTime }}
           END=${{ steps.end-time.outputs.formattedTime }}
@@ -58,12 +62,19 @@ jobs:
 
 
       - name: Compress cache
+        # Always compress the cache so we can update the cache if needed.
+        if: always()
         run: rm -rf $(bazel info repository_cache)
 
       - name: Save bazel cache
         uses: actions/cache/save@v4
         # Only create a new cache entry if we're on the main branch or the build takes >5mins.
-        if: github.ref_name == 'main' || env.duration > 300
+        #
+        # NOTE: Even though `always()` evaluates to true, and `true && x == x`, the `always() &&`
+        # prefix is not redundant! The call to `always()` has a side effect, which is to override
+        # the default behavior of automagically canceling this step if a previous step failed.
+        # (Don't blame me, blame GitHub Actions!)
+        if: always() && (github.ref_name == 'main' || env.duration > 300)
         with:
           path: "~/.cache/bazel"
           key: bazel-${{ hashFiles('*.bazel', '*.bazelrc') }}-${{ github.ref_name }}-${{ github.run_id }}