Use a separate build structure for maintaining fork (#3064)

Part of [CMP-10017](https://youtrack.jetbrains.com/issue/CMP-10017)
Simplify merges short-term. Make buildSrc/build.gradle for the fork mode

The reason is to simplify regular AOSP merges.

There are 2 modes:
- AOSP mode. used if it is opened via `gradlew studio`
- fork mode. used if it is opened via IDEA.

The build fork is separated using this code:
```
def isRunFromGradlewStudio = System.getenv().get("EXPECTED_AGP_VERSION")
if (!isRunFromGradlewStudio) {
    apply from: "settings-fork.gradle"
    return
}
```

This works, but not ideally because some parts of the build are still
shared with AOSP and we need to review them during the merge:
```
gradle.properties
gradle/wrapper
gradle/libs.version.toml
buildSrc/gradle.properties
```
Alternatives that I tried:
- create `fork-project`, add symlinks to the top-level projects. Didn't
work because integration with Git is broken (the changed files are
treated as not a part of the project)
- create `fork-project`, use `../project` paths to the top-level
projects. Didn't work because running from the gutter is broken (IDEA
tells that the project folder isn't part of the root project)

Next steps:
1. [Support using sources instead of androidx
artifacts](#3169)
2. Merge it into `integration`
3. Reset state of `buildSrc`, `build.gradle` to the AOSP state
(excluding the code that redirects to the fork)
4. Add an automatic task that compares source sets dependencies inside
`build-fork.gradle`
5. Clean up `buildSrc` from not needed code


[TeamCity](https://teamcity.jetbrains.com/buildConfiguration/JetBrainsPublicProjects_Compose_AllPersonalBuild/6263205)

Should be reviewed commit by commit.

## Release Notes
N/A

Author: igordmn

annotation/annotation-sampled/build-fork.gradle

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * 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
+ *
+ *      http://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.
+ */
+
+plugins {
+    id("AndroidXPlugin")
+    id("kotlin")
+}
+
+dependencies {
+}
+

build-fork.gradle

@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * 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
+ *
+ *      http://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.
+ */
+
+/**
+ * This file was created using the `create_project.py` script located in the
+ * `<AndroidX root>/development/project-creator` directory.
+ *
+ * Please use that script when creating a new project, rather than copying an existing project and
+ * modifying its settings.
+ */
+import androidx.build.AndroidXRootPlugin
+import androidx.build.SdkHelperKt
+import org.jetbrains.androidx.build.JetBrainsAndroidXRootPlugin
+
+buildscript {
+    SdkHelperKt.setSupportRootFolder(project, project.projectDir)
+
+    // Needed for atomicfu plugin
+    apply(from: "buildSrc/repos.gradle")
+    repos.addMavenRepositories(repositories)
+}
+
+apply plugin: AndroidXRootPlugin
+apply plugin: JetBrainsAndroidXRootPlugin

buildSrc-fork/build.gradle

@@ -0,0 +1,32 @@
+buildscript {
+    project.ext.supportRootFolder = project.projectDir.getParentFile()
+    apply from: "repos.gradle"
+    repos.addMavenRepositories(repositories)
+
+    dependencies {
+        classpath(libs.kotlinGradlePlugin)
+    }
+
+    configurations.classpath.resolutionStrategy {
+        eachDependency { details ->
+            if (details.requested.group == "org.jetbrains.kotlin") {
+                details.useVersion libs.versions.kotlin.get()
+            }
+        }
+    }
+}
+
+ext.supportRootFolder = project.projectDir.getParentFile()
+apply from: "repos.gradle"
+apply plugin: "kotlin"
+
+repos.addMavenRepositories(repositories)
+
+project.tasks.withType(Jar).configureEach { task ->
+    task.reproducibleFileOrder = true
+    task.preserveFileTimestamps = false
+}
+
+dependencies {
+    api(project("plugins"))
+}

buildSrc-fork/imports/README.md

@@ -0,0 +1,3 @@
+This directory contains projects that just mirror the corresponding project in the main build in ../..
+
+This may be useful if a project in ../.. creates a plugin that another project wants to apply

buildSrc-fork/imports/baseline-profile-gradle-plugin/build.gradle

@@ -0,0 +1,30 @@
+apply from: "../../shared.gradle"
+apply plugin: "java-gradle-plugin"
+
+sourceSets {
+    main.java.srcDirs += "${supportRootFolder}" +
+            "/benchmark/baseline-profile-gradle-plugin/src/main/kotlin"
+    main.resources.srcDirs += "${supportRootFolder}" +
+            "/benchmark/baseline-profile-gradle-plugin/src/main/resources"
+}
+
+gradlePlugin {
+    plugins {
+        baselineProfileProducer {
+            id = "androidx.baselineprofile.producer"
+            implementationClass = "androidx.baselineprofile.gradle.producer.BaselineProfileProducerPlugin"
+        }
+        baselineProfileConsumer {
+            id = "androidx.baselineprofile.consumer"
+            implementationClass = "androidx.baselineprofile.gradle.consumer.BaselineProfileConsumerPlugin"
+        }
+        baselineProfileAppTarget {
+            id = "androidx.baselineprofile.apptarget"
+            implementationClass = "androidx.baselineprofile.gradle.apptarget.BaselineProfileAppTargetPlugin"
+        }
+        baselineProfileWrapper {
+            id = "androidx.baselineprofile"
+            implementationClass = "androidx.baselineprofile.gradle.wrapper.BaselineProfileWrapperPlugin"
+        }
+    }
+}

buildSrc-fork/imports/benchmark-darwin-plugin/build.gradle

@@ -0,0 +1,20 @@
+apply from: "../../shared.gradle"
+apply plugin: "java-gradle-plugin"
+
+sourceSets {
+    main.java.srcDirs += "${supportRootFolder}/benchmark/benchmark-darwin-gradle-plugin/src/main/kotlin"
+    main.resources.srcDirs += "${supportRootFolder}/benchmark/benchmark-darwin-gradle-plugin/src/main/resources"
+}
+
+dependencies {
+    implementation(libs.apacheCommonsMath)
+}
+
+gradlePlugin {
+    plugins {
+        darwinBenchmark {
+            id = "androidx.benchmark.darwin"
+            implementationClass = "androidx.benchmark.darwin.gradle.DarwinBenchmarkPlugin"
+        }
+    }
+}

buildSrc-fork/imports/benchmark-gradle-plugin/build.gradle

@@ -0,0 +1,16 @@
+apply from: "../../shared.gradle"
+apply plugin: "java-gradle-plugin"
+
+sourceSets {
+    main.java.srcDirs += "${supportRootFolder}/benchmark/gradle-plugin/src/main/kotlin"
+    main.resources.srcDirs += "${supportRootFolder}/benchmark/gradle-plugin/src/main/resources"
+}
+
+gradlePlugin {
+    plugins {
+        benchmark {
+            id = "androidx.benchmark"
+            implementationClass = "androidx.benchmark.gradle.BenchmarkPlugin"
+        }
+    }
+}

buildSrc-fork/imports/binary-compatibility-validator/build.gradle

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2024 The Android Open Source Project
+ *
+ * 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
+ *
+ *      http://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.
+ */
+
+apply from: "../../shared.gradle"
+
+// TODO(b/410631668): remove when "kotlin-compiler" is no longer added to "friendPaths"
+// Workaround for Windows to solve
+// "this and base files have different roots: C:\Users\User\.gradle\caches\modules-2\...\kotlin-compiler-2.2.10.jar and D:\compose-multiplatform-core\out\buildSrc\imports\binary-compatibility-validator\build"
+//
+// This happens because "friendPaths" is set and it doesn't support different roots (C: and D:)
+// kotlin-compiler was added to "friendsPath" in
+// https://android-review.googlesource.com/c/platform/frameworks/support/+/3636427
+//
+// This moves the build directory to the Gradle cache directory for this module,
+// which is an anti-pattern but solves the issue
+if (System.properties['os.name']?.toString()?.toLowerCase()?.contains('windows') == true) {
+    layout.buildDirectory = file("${gradle.gradleUserHomeDir}/compose-multipltform-core-build/buildSrc-imports-binary-compatibility-validator")
+}
+
+sourceSets {
+    main.java.srcDirs += "${supportRootFolder}/binarycompatibilityvalidator/" +
+            "binarycompatibilityvalidator/src/jvmMain/kotlin"
+}

buildSrc-fork/imports/glance-layout-generator/build.gradle

@@ -0,0 +1,6 @@
+apply from: "../../shared.gradle"
+
+sourceSets {
+    main.java.srcDirs += "${supportRootFolder}/glance/glance-appwidget/glance-layout-generator/" +
+            "src/main/kotlin"
+}

buildSrc-fork/imports/inspection-gradle-plugin/build.gradle

@@ -0,0 +1,17 @@
+apply from: "../../shared.gradle"
+apply plugin: "java-gradle-plugin"
+
+sourceSets {
+    main.java.srcDirs += "${supportRootFolder}/inspection/inspection-gradle-plugin/src/main/kotlin"
+    main.resources.srcDirs += "${supportRootFolder}/inspection/inspection-gradle-plugin/src/main" +
+            "/resources"
+}
+
+gradlePlugin {
+    plugins {
+        inspection {
+            id = "androidx.inspection"
+            implementationClass = "androidx.inspection.gradle.InspectionPlugin"
+        }
+    }
+}