Merge "Modify symlink_forest to rerun when soong_build has changed." into main

	"regexp"

	"sort"

	"strconv"

	"strings"

	"sync"

	"sync/atomic"

)

// 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

	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)

	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)

	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)

		}

		err = os.RemoveAll(shared.JoinPath(topdir, forest))

// 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 {

			return err

		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 nil

	return info.ModTime().UnixMilli()

}

// 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) {

// 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

	}

		err = os.WriteFile(versionFilePath, []byte(strconv.Itoa(symlinkForestVersion)+"\n"), 0666)

	if string(soongBuildMTime) != string(mtimeFileContents) {

		err = os.RemoveAll(shared.JoinPath(topdir, forest))

		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

// contain every file in buildFilesDir and srcDir excluding the files in

// instructions. Collects every directory encountered during the traversal of

		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)

		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()

}

"$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

#!/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