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src/main/java/com/google/devtools/build/lib/analysis/SourceManifestAction.java

@@ -302,6 +302,9 @@ public void writeEntry(
           @Nullable PathFragment symlinkTarget)
           throws IOException {
         String rootRelativePathString = rootRelativePath.getPathString();
+        // Source paths with spaces require escaping. Target paths with spaces don't as consumers
+        // are expected to split on the first space (without escaping) or after the part indicated
+        // by the length prefix (with escaping).
         if (rootRelativePathString.indexOf(' ') != -1) {
           manifestWriter.append(' ');
           manifestWriter.append(String.valueOf(rootRelativePathString.length()));

src/test/shell/bazel/bazel_determinism_test.sh

@@ -61,6 +61,7 @@ function hash_outputs() {
 }
 
 function test_determinism()  {
+    # Verify that Bazel can build itself under a path with spaces.
     local workdir="${TEST_TMPDIR}/work dir"
     mkdir "${workdir}" || fail "Could not create work directory"
     cd "${workdir}" || fail "Could not change to work directory"

tools/java/runfiles/Runfiles.java

@@ -157,9 +157,10 @@ public boolean equals(Object o) {
         if (this == o) {
           return true;
         }
-        if (!(o instanceof RepoMappingKey that)) {
+        if (o == null || !(o instanceof RepoMappingKey)) {
           return false;
         }
+        RepoMappingKey that = (RepoMappingKey) o;
         return sourceRepo.equals(that.sourceRepo)
             && targetRepoApparentName.equals(that.targetRepoApparentName);
       }