Add experimental support for cache-cleanup

- Includes basic implementation as `CacheCleaner`
- Integration test that checks unused files are removed:
  - Downloaded dependencies
  - Local build cache entries
  - Wrapper distributions

action.yml

@@ -70,6 +70,10 @@ inputs:
     description: Used to uniquely identify the current job invocation. Defaults to the matrix values for this job; this should not be overridden by users (INTERNAL).
     required: false
     default: ${{ toJSON(matrix) }}
+  gradle-home-cache-cleanup:
+    description: When 'true', the action will attempt to remove any stale/unused entries from the Gradle User Home prior to saving to the GitHub Actions cache.
+    required: false
+    default: false
 
 outputs:
   build-scan-url:

src/cache-cleaner.ts

@@ -0,0 +1,52 @@
+import * as exec from '@actions/exec'
+import fs from 'fs'
+import path from 'path'
+
+export class CacheCleaner {
+    private readonly gradleUserHome: string
+    private readonly tmpDir: string
+
+    constructor(gradleUserHome: string, tmpDir: string) {
+        this.gradleUserHome = gradleUserHome
+        this.tmpDir = tmpDir
+    }
+
+    async prepare(): Promise<void> {
+        fs.rmSync(path.resolve(this.gradleUserHome, 'caches/journal-1'), {recursive: true, force: true})
+        fs.mkdirSync(path.resolve(this.gradleUserHome, 'caches/journal-1'), {recursive: true})
+        fs.writeFileSync(
+            path.resolve(this.gradleUserHome, 'caches/journal-1/file-access.properties'),
+            'inceptionTimestamp=0'
+        )
+        await this.ageAllFiles()
+        await this.touchAllFiles('gc.properties')
+    }
+
+    async forceCleanup(): Promise<void> {
+        await this.ageAllFiles('gc.properties')
+
+        const cleanupProjectDir = path.resolve(this.tmpDir, 'dummy-cleanup-project')
+        fs.mkdirSync(cleanupProjectDir, {recursive: true})
+        fs.writeFileSync(
+            path.resolve(cleanupProjectDir, 'settings.gradle'),
+            'rootProject.name = "dummy-cleanup-project"'
+        )
+        fs.writeFileSync(path.resolve(cleanupProjectDir, 'build.gradle'), 'task("noop") {}')
+
+        await exec.exec(`gradle -g ${this.gradleUserHome} --no-daemon --build-cache --no-scan --quiet noop`, [], {
+            cwd: cleanupProjectDir
+        })
+    }
+
+    private async ageAllFiles(fileName = '*'): Promise<void> {
+        await exec.exec(
+            'find',
+            [this.gradleUserHome, '-name', fileName, '-exec', 'touch', '-m', '-d', '1970-01-01', '{}', '+'],
+            {}
+        )
+    }
+
+    private async touchAllFiles(fileName = '*'): Promise<void> {
+        await exec.exec('find', [this.gradleUserHome, '-name', fileName, '-exec', 'touch', '-m', '{}', '+'], {})
+    }
+}

src/cache-utils.ts

@@ -16,6 +16,7 @@ const CACHE_DISABLED_PARAMETER = 'cache-disabled'
 const CACHE_READONLY_PARAMETER = 'cache-read-only'
 const CACHE_WRITEONLY_PARAMETER = 'cache-write-only'
 const STRICT_CACHE_MATCH_PARAMETER = 'gradle-home-cache-strict-match'
+const CACHE_CLEANUP_ENABLED_PARAMETER = 'gradle-home-cache-cleanup'
 const CACHE_DEBUG_VAR = 'GRADLE_BUILD_ACTION_CACHE_DEBUG_ENABLED'
 
 const CACHE_KEY_PREFIX_VAR = 'GRADLE_BUILD_ACTION_CACHE_KEY_PREFIX'
@@ -46,6 +47,10 @@ export function isCacheDebuggingEnabled(): boolean {
     return process.env[CACHE_DEBUG_VAR] ? true : false
 }
 
+export function isCacheCleanupEnabled(): boolean {
+    return core.getBooleanInput(CACHE_CLEANUP_ENABLED_PARAMETER)
+}
+
 /**
  * Represents a key used to restore a cache entry.
  * The Github Actions cache will first try for an exact match on the key.

src/caches.ts

@@ -1,8 +1,9 @@
 import * as core from '@actions/core'
-import {isCacheDisabled, isCacheReadOnly, isCacheWriteOnly} from './cache-utils'
+import {isCacheCleanupEnabled, isCacheDisabled, isCacheReadOnly, isCacheWriteOnly} from './cache-utils'
 import {CacheListener} from './cache-reporting'
 import {DaemonController} from './daemon-controller'
 import {GradleStateCache} from './cache-base'
+import {CacheCleaner} from './cache-cleaner'
 
 const CACHE_RESTORED_VAR = 'GRADLE_BUILD_ACTION_CACHE_RESTORED'
 
@@ -44,6 +45,10 @@ export async function restore(gradleUserHome: string, cacheListener: CacheListen
     await core.group('Restore Gradle state from cache', async () => {
         await gradleStateCache.restore(cacheListener)
     })
+
+    if (isCacheCleanupEnabled() && !isCacheReadOnly()) {
+        new CacheCleaner(gradleUserHome, process.env['RUNNER_TEMP']!).prepare()
+    }
 }
 
 export async function save(
@@ -69,6 +74,10 @@ export async function save(
 
     await daemonController.stopAllDaemons()
 
+    if (isCacheCleanupEnabled()) {
+        new CacheCleaner(gradleUserHome, process.env['RUNNER_TEMP']!).forceCleanup()
+    }
+
     await core.group('Caching Gradle state', async () => {
         return new GradleStateCache(gradleUserHome).save(cacheListener)
     })

test/jest/cache-cleanup.test.ts

@@ -0,0 +1,87 @@
+import * as exec from '@actions/exec'
+import fs from 'fs'
+import path from 'path'
+import {CacheCleaner} from '../../src/cache-cleaner'
+
+jest.setTimeout(120000)
+
+test('will cleanup unused dependency jars and build-cache entries', async () => {
+    const projectRoot = prepareTestProject()
+    const gradleUserHome = path.resolve(projectRoot, 'HOME')
+    const tmpDir = path.resolve(projectRoot, 'tmp')
+    const cacheCleaner = new CacheCleaner(gradleUserHome, tmpDir)
+
+    await runGradleBuild(projectRoot, 'build', '3.1')
+    
+    await cacheCleaner.prepare()
+
+    await runGradleBuild(projectRoot, 'build', '3.1.1')
+
+    const commonsMath31 = path.resolve(gradleUserHome, "caches/modules-2/files-2.1/org.apache.commons/commons-math3/3.1")
+    const commonsMath311 = path.resolve(gradleUserHome, "caches/modules-2/files-2.1/org.apache.commons/commons-math3/3.1.1")
+    const buildCacheDir = path.resolve(gradleUserHome, "caches/build-cache-1")
+
+    expect(fs.existsSync(commonsMath31)).toBe(true)
+    expect(fs.existsSync(commonsMath311)).toBe(true)
+    expect(fs.readdirSync(buildCacheDir).length).toBe(4)
+
+    await cacheCleaner.forceCleanup()
+
+    expect(fs.existsSync(commonsMath31)).toBe(false)
+    expect(fs.existsSync(commonsMath311)).toBe(true)
+    expect(fs.readdirSync(buildCacheDir).length).toBe(3)
+})
+
+test('will cleanup unused gradle versions', async () => {
+    const projectRoot = prepareTestProject()
+    const gradleUserHome = path.resolve(projectRoot, 'HOME')
+    const tmpDir = path.resolve(projectRoot, 'tmp')
+    const cacheCleaner = new CacheCleaner(gradleUserHome, tmpDir)
+
+    // Initialize HOME with 2 different Gradle versions
+    await runGradleWrapperBuild(projectRoot, 'build')
+    await runGradleBuild(projectRoot, 'build')
+    
+    await cacheCleaner.prepare()
+
+    // Run with only one of these versions
+    await runGradleBuild(projectRoot, 'build')
+
+    const gradle733 = path.resolve(gradleUserHome, "caches/7.3.3")
+    const wrapper733 = path.resolve(gradleUserHome, "wrapper/dists/gradle-7.3.3-bin")
+    const gradleCurrent = path.resolve(gradleUserHome, "caches/7.5.1")
+
+    expect(fs.existsSync(gradle733)).toBe(true)
+    expect(fs.existsSync(wrapper733)).toBe(true)
+    expect(fs.existsSync(gradleCurrent)).toBe(true)
+
+    await cacheCleaner.forceCleanup()
+
+    expect(fs.existsSync(gradle733)).toBe(false)
+    expect(fs.existsSync(wrapper733)).toBe(false)
+    expect(fs.existsSync(gradleCurrent)).toBe(true)
+})
+
+async function runGradleBuild(projectRoot: string, args: string, version: string = '3.1'): Promise<void> {
+    const status31 = await exec.exec(`gradle -g HOME --no-daemon --build-cache -Dcommons-math3.version=${version} ${args}`, [], {
+        cwd: projectRoot
+    })
+    console.log(`Gradle User Home initialized with commons-math3.version=${version} ${args}`)
+}
+
+async function runGradleWrapperBuild(projectRoot: string, args: string, version: string = '3.1'): Promise<void> {
+    const status31 = await exec.exec(`./gradlew -g HOME --no-daemon --build-cache -Dcommons-math3.version=${version} ${args}`, [], {
+        cwd: projectRoot
+    })
+    console.log(`Gradle User Home initialized with commons-math3.version=${version} ${args}`)
+}
+
+function prepareTestProject(): string {
+    const projectRoot = 'test/jest/resources/cache-cleanup'
+    fs.rmSync(path.resolve(projectRoot, 'HOME'), { recursive: true, force: true })
+    fs.rmSync(path.resolve(projectRoot, 'tmp'), { recursive: true, force: true })
+    fs.rmSync(path.resolve(projectRoot, 'build'), { recursive: true, force: true })
+    fs.rmSync(path.resolve(projectRoot, '.gradle'), { recursive: true, force: true })
+    return projectRoot
+}
+

test/jest/resources/cache-cleanup/.gitattributes

@@ -0,0 +1,6 @@
+#
+# https://help.github.com/articles/dealing-with-line-endings/
+#
+# These are explicitly windows files and should use crlf
+*.bat           text eol=crlf
+

test/jest/resources/cache-cleanup/.gitignore

@@ -0,0 +1,8 @@
+# Ignore Gradle project-specific cache directory
+.gradle
+
+# Ignore Gradle build output directory
+build
+
+HOME
+tmp

test/jest/resources/cache-cleanup/build.gradle

@@ -0,0 +1,11 @@
+plugins {
+    id 'java-library'
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    api "org.apache.commons:commons-math3:${System.properties['commons-math3.version']}"
+}

test/jest/resources/cache-cleanup/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.3.3-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

test/jest/resources/cache-cleanup/gradlew

@@ -0,0 +1,234 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+APP_NAME="Gradle"
+APP_BASE_NAME=${0##*/}
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

test/jest/resources/cache-cleanup/gradlew.bat

@@ -0,0 +1,89 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

test/jest/resources/cache-cleanup/settings.gradle

@@ -0,0 +1 @@
+rootProject.name = 'unused-dependencies'

test/jest/resources/cache-cleanup/src/main/java/unused/dependencies/Library.java

@@ -0,0 +1,10 @@
+/*
+ * This Java source file was generated by the Gradle 'init' task.
+ */
+package unused.dependencies;
+
+public class Library {
+    public boolean someLibraryMethod() {
+        return true;
+    }
+}