Fix issue merging bp2build files with handcrafted ones
It was possible for the merged content to end up back in the bp2build
generated file because there was a symlink from the symlink forest to
the bp2build generated file.
Remove the symlink if it exists.
Bug: 276349152
Test: m bp2build, add a handcrafted file in the same folder as a Android.bp file, m bp2build again, check that the symlink forest version is not a symlink
Change-Id: Id64aa3addebcf0c6b1728389f21ae246796aaf8d
diff --git a/bp2build/symlink_forest.go b/bp2build/symlink_forest.go
index aac5e7d..e3878b1 100644
--- a/bp2build/symlink_forest.go
+++ b/bp2build/symlink_forest.go
@@ -25,6 +25,7 @@
"sync/atomic"
"android/soong/shared"
+
"github.com/google/blueprint/pathtools"
)
@@ -123,6 +124,34 @@
}
newContents = append(newContents, srcBuildFileContent...)
+ // Say you run bp2build 4 times:
+ // - The first time there's only an Android.bp file. bp2build will convert it to a build file
+ // under out/soong/bp2build, then symlink from the forest to that generated file
+ // - Then you add a handcrafted BUILD file in the same directory. bp2build will merge this with
+ // the generated one, and write the result to the output file in the forest. But the output
+ // file was a symlink to out/soong/bp2build from the previous step! So we erroneously update
+ // the file in out/soong/bp2build instead. So far this doesn't cause any problems...
+ // - You run a 3rd bp2build with no relevant changes. Everything continues to work.
+ // - You then add a comment to the handcrafted BUILD file. This causes a merge with the
+ // generated file again. But since we wrote to the generated file in step 2, the generated
+ // file has an old copy of the handcrafted file in it! This probably causes duplicate bazel
+ // targets.
+ // To solve this, if we see that the output file is a symlink from a previous build, remove it.
+ stat, err := os.Lstat(output)
+ if err != nil && !os.IsNotExist(err) {
+ return err
+ } else if err == nil {
+ if stat.Mode()&os.ModeSymlink == os.ModeSymlink {
+ if verbose {
+ fmt.Fprintf(os.Stderr, "Removing symlink so that we can replace it with a merged file: %s\n", output)
+ }
+ err = os.Remove(output)
+ if err != nil {
+ return err
+ }
+ }
+ }
+
return pathtools.WriteFileIfChanged(output, newContents, 0666)
}