diff --git a/bp2build/symlink_forest.go b/bp2build/symlink_forest.go index 966b94a80..06e63ca4d 100644 --- a/bp2build/symlink_forest.go +++ b/bp2build/symlink_forest.go @@ -22,7 +22,6 @@ import ( "regexp" "sort" "strconv" - "strings" "sync" "sync/atomic" @@ -32,19 +31,12 @@ import ( ) // A tree structure that describes what to do at each directory in the created -// symlink tree. Currently it is used to enumerate which files/directories +// symlink tree. Currently, it is used to enumerate which files/directories // should be excluded from symlinking. Each instance of "node" represents a file // or a directory. If excluded is true, then that file/directory should be // excluded from symlinking. Otherwise, the node is not excluded, but one of its // descendants is (otherwise the node in question would not exist) -// This is a version int written to a file called symlink_forest_version at the root of the -// symlink forest. If the version here does not match the version in the file, then we'll -// clean the whole symlink forest and recreate it. This number can be bumped whenever there's -// an incompatible change to the forest layout or a bug in incrementality that needs to be fixed -// on machines that may still have the bug present in their forest. -const symlinkForestVersion = 2 - type instructionsNode struct { name string excluded bool // If false, this is just an intermediate node @@ -193,7 +185,7 @@ func symlinkIntoForest(topdir, dst, src string) uint64 { srcPath := shared.JoinPath(topdir, src) dstPath := shared.JoinPath(topdir, dst) - // Check if a symlink already exists. + // Check whether a symlink already exists. if dstInfo, err := os.Lstat(dstPath); err != nil { if !os.IsNotExist(err) { fmt.Fprintf(os.Stderr, "Failed to lstat '%s': %s", dst, err) @@ -240,44 +232,49 @@ func isDir(path string, fi os.FileInfo) bool { return false } -// maybeCleanSymlinkForest will remove the whole symlink forest directory if the version recorded -// in the symlink_forest_version file is not equal to symlinkForestVersion. -func maybeCleanSymlinkForest(topdir, forest string, verbose bool) error { - versionFilePath := shared.JoinPath(topdir, forest, "symlink_forest_version") - versionFileContents, err := os.ReadFile(versionFilePath) +// Returns the hash of the soong_build binary to determine whether we should +// force symlink_forest to re-execute +// This is similar to a version number increment - but that shouldn't be required +// for every update to this file +func getSoongBuildMTime() int64 { + binaryPath, err := os.Executable() + if err != nil { + fmt.Fprintf(os.Stderr, "error finding executable path %s\n", err) + os.Exit(1) + } + + info, err := os.Stat(binaryPath) + if err != nil { + fmt.Fprintf(os.Stderr, "error stating executable path %s\n", err) + } + + return info.ModTime().UnixMilli() +} + +// maybeCleanSymlinkForest will remove the whole symlink forest directory if the soong_build +// binary has changed since the last execution. +func maybeCleanSymlinkForest(topdir, forest string, verbose bool, soongBuildMTime int64) error { + mtimeFilePath := shared.JoinPath(topdir, forest, "soong_build_mtime") + mtimeFileContents, err := os.ReadFile(mtimeFilePath) if err != nil && !os.IsNotExist(err) { return err } - versionFileString := strings.TrimSpace(string(versionFileContents)) - symlinkForestVersionString := strconv.Itoa(symlinkForestVersion) - if err != nil || versionFileString != symlinkForestVersionString { - if verbose { - fmt.Fprintf(os.Stderr, "Old symlink_forest_version was %q, current is %q. Cleaning symlink forest before recreating...\n", versionFileString, symlinkForestVersionString) - } + + if string(soongBuildMTime) != string(mtimeFileContents) { err = os.RemoveAll(shared.JoinPath(topdir, forest)) if err != nil { return err } } + return nil } -// maybeWriteVersionFile will write the symlink_forest_version file containing symlinkForestVersion -// if it doesn't exist already. If it exists we know it must contain symlinkForestVersion because -// we checked for that already in maybeCleanSymlinkForest -func maybeWriteVersionFile(topdir, forest string) error { - versionFilePath := shared.JoinPath(topdir, forest, "symlink_forest_version") - _, err := os.Stat(versionFilePath) - if err != nil { - if !os.IsNotExist(err) { - return err - } - err = os.WriteFile(versionFilePath, []byte(strconv.Itoa(symlinkForestVersion)+"\n"), 0666) - if err != nil { - return err - } - } - return nil +func writeSoongBuildMTimeFile(topdir, forest string, mtime int64) error { + hashFilePath := shared.JoinPath(topdir, forest, "soong_build_mtime") + contents := []byte(strconv.FormatInt(mtime, 10)) + + return os.WriteFile(hashFilePath, contents, 0666) } // Recursively plants a symlink forest at forestDir. The symlink tree will @@ -473,7 +470,10 @@ func PlantSymlinkForest(verbose bool, topdir string, forest string, buildFiles s symlinkCount: atomic.Uint64{}, } - err := maybeCleanSymlinkForest(topdir, forest, verbose) + // Check whether soong_build has been modified since the last run + soongBuildMTime := getSoongBuildMTime() + + err := maybeCleanSymlinkForest(topdir, forest, verbose, soongBuildMTime) if err != nil { fmt.Fprintln(os.Stderr, err) os.Exit(1) @@ -491,11 +491,10 @@ func PlantSymlinkForest(verbose bool, topdir string, forest string, buildFiles s deps = append(deps, dep) } - err = maybeWriteVersionFile(topdir, forest) + err = writeSoongBuildMTimeFile(topdir, forest, soongBuildMTime) if err != nil { fmt.Fprintln(os.Stderr, err) os.Exit(1) } - return deps, context.mkdirCount.Load(), context.symlinkCount.Load() } diff --git a/tests/run_integration_tests.sh b/tests/run_integration_tests.sh index 6b9ff8b93..234999376 100755 --- a/tests/run_integration_tests.sh +++ b/tests/run_integration_tests.sh @@ -10,6 +10,7 @@ TOP="$(readlink -f "$(dirname "$0")"/../../..)" "$TOP/build/soong/tests/persistent_bazel_test.sh" "$TOP/build/soong/tests/soong_test.sh" "$TOP/build/soong/tests/stale_metrics_files_test.sh" +"$TOP/build/soong/tests/symlink_forest_rerun_test.sh" "$TOP/prebuilts/build-tools/linux-x86/bin/py3-cmd" "$TOP/build/bazel/ci/rbc_dashboard.py" aosp_arm64-userdebug # The following tests build against the full source tree and don't rely on the diff --git a/tests/symlink_forest_rerun_test.sh b/tests/symlink_forest_rerun_test.sh new file mode 100755 index 000000000..b704222e2 --- /dev/null +++ b/tests/symlink_forest_rerun_test.sh @@ -0,0 +1,42 @@ +#!/bin/bash -eu + +set -o pipefail + +# Tests that symlink_Forest will rerun if soong_build has schanged + +source "$(dirname "$0")/lib.sh" + +function test_symlink_forest_reruns { + setup + + mkdir -p a + touch a/g.txt + cat > a/Android.bp <<'EOF' +filegroup { + name: "g", + srcs: ["g.txt"], + } +EOF + + run_soong g + + mtime=`cat out/soong/workspace/soong_build_mtime` + # rerun with no changes - ensure that it hasn't changed + run_soong g + newmtime=`cat out/soong/workspace/soong_build_mtime` + if [[ ! "$mtime" == "$mtime" ]]; then + fail "symlink forest reran when it shouldn't have" + fi + + # change exit codes to force a soong_build rebuild. + sed -i 's/os.Exit(1)/os.Exit(2)/g' build/soong/bp2build/symlink_forest.go + + run_soong g + newmtime=`cat out/soong/workspace/soong_build_mtime` + if [[ "$mtime" == "$newmtime" ]]; then + fail "symlink forest did not rerun when it should have" + fi + +} + +scan_and_run_tests