PrePush: Add a pre-push warning before committing to locked branches

libraries/tools/kotlin-prepush-hook/build.gradle.kts

@@ -0,0 +1,40 @@
+import org.gradle.api.Project
+import java.io.File
+
+apply { plugin("java") }
+apply { plugin("jps-compatible") }
+
+jvmTarget = "1.6"
+
+sourceSets {
+    "main" { projectDefault() }
+    "test" {}
+}
+
+project.addPrePushHookIfMissing()
+
+fun Project.addPrePushHookIfMissing() {
+    val dotGitDirectory = rootProject.getGitDirectory()
+    val hooksDirectory = File(dotGitDirectory, "hooks").also { it.mkdirs() }
+
+    val prePushHook = File(projectDir, "pre-push.sh").also { require(it.exists()) }
+    val prePushTarget = File(hooksDirectory, "pre-push")
+    prePushHook.copyTo(prePushTarget, overwrite = true)
+    prePushTarget.setExecutable(true, true)
+}
+
+fun Project.getGitDirectory(): File {
+    val dotGitFile = File(projectDir, ".git")
+
+    return if (dotGitFile.isFile) {
+        val workTreeLink = dotGitFile.readLines().single { it.startsWith("gitdir: ") }
+        val mainRepoPath = workTreeLink
+            .substringAfter("gitdir: ", "")
+            .substringBefore("/.git/worktrees/", "")
+            .also { require(it.isNotEmpty()) }
+
+        File(mainRepoPath, ".git").also { require(it.isDirectory) }
+    } else {
+        dotGitFile
+    }
+}

libraries/tools/kotlin-prepush-hook/pre-push.sh

@@ -0,0 +1,61 @@
+#!/bin/sh
+
+targetRepo="$2"
+
+remoteRefs=""
+
+javacPath="$JAVA_HOME/bin/javac"
+javaPath="$JAVA_HOME/bin/java"
+
+if [ -f "~/.kotlin-deactivate-prepush-hook" ]; then
+    echo "Pre-commit hook is deactivated"
+    exit 0
+fi
+
+if [ ! -f "./libraries/tools/kotlin-prepush-hook/src/KotlinPrePushHook.java" ]; then
+    echo "Pre-commit hook .java file was not found in current branch, pre-push hook is disabled"
+    exit 0
+fi
+
+if [ ! -f "$javaPath" ]; then
+    echo "'java' ($javaPath) was not found, pre-push hook is disabled"
+    exit 0
+fi
+
+if [ ! -f "$javacPath" ]; then
+    echo "'javac' ($javacPath) was not found, pre-push hook is disabled"
+    exit 0
+fi
+
+while read localRef localSha remoteRef remoteSha
+do
+    # Looks like there're no [[ in Ubuntu by default
+    if [ "$remoteRef" = "refs/heads/rr/"* ]; then
+        continue
+    fi
+
+    if [ "$remoteRef" = "refs/heads/rrr/"* ]; then
+        continue
+    fi
+
+    if [ -z $remoteRefs ]; then
+        remoteRefs="$remoteRef"
+    else
+        remoteRefs="$remoteRefs,$remoteRef"
+    fi
+done
+
+if [ -z "$remoteRefs" ]; then
+    exit 0
+fi
+
+mkdir -p ./build/prePushHook
+"$javacPath" -d ./build/prePushHook ./libraries/tools/kotlin-prepush-hook/src/KotlinPrePushHook.java
+cd ./build/prePushHook
+
+"$javaPath" KotlinPrePushHook "$remoteRefs" "$targetRepo"
+returnCode=$?
+
+cd ../..
+
+exit $returnCode

libraries/tools/kotlin-prepush-hook/src/KotlinPrePushHook.java

@@ -0,0 +1,111 @@
+import javax.swing.*;
+import java.io.InputStream;
+import java.net.URL;
+import java.net.URLConnection;
+import java.util.*;
+import java.util.stream.Collectors;
+
+public class KotlinPrePushHook {
+    private static final String BRANCH_DATA_URL = "https://raw.githubusercontent.com/Kotlin/kotlin-branch-status/master/status.txt";
+    private static final String MESSAGE_PREFIX = "MESSAGE.";
+
+    private static final List<String> KOTLIN_GIT_REPOS = Arrays.asList(
+            "git@github.com:JetBrains/kotlin.git",
+            "https://github.com/JetBrains/kotlin.git");
+
+    private static final String REF_PREFIX = "refs/heads/";
+
+    public static void main(String[] args) throws Exception {
+        if (args.length != 2) {
+            error("Usage: <remote refs> <target repository>, got " + Arrays.toString(args));
+        }
+
+        List<String> remoteRefs = Arrays
+                .stream(args[0].split(","))
+                .filter(ref -> ref.startsWith(REF_PREFIX))
+                .map(ref -> ref.substring(REF_PREFIX.length())).collect(Collectors.toList());
+
+        String targetRepo = args[1];
+
+        if (!KOTLIN_GIT_REPOS.contains(targetRepo)) {
+            return;
+        }
+
+        check(remoteRefs);
+    }
+
+    private static void check(List<String> remoteRefs) throws Exception {
+        Map<String, String> branchProperties = getProperties(new URL(BRANCH_DATA_URL));
+
+        Map<String, String> messages = new HashMap<>();
+        Map<String, String> branches = new HashMap<>();
+
+        for (Map.Entry<String, String> entry : branchProperties.entrySet()) {
+            String key = entry.getKey();
+            String value = entry.getValue();
+
+            if (key.startsWith(MESSAGE_PREFIX)) {
+                messages.put(key.substring(MESSAGE_PREFIX.length()), value);
+            } else {
+                branches.put(key, value);
+            }
+        }
+
+        for (Map.Entry<String, String> entry : branches.entrySet()) {
+            String branchName = entry.getKey();
+
+            if (remoteRefs.contains(branchName)) {
+                String message = messages.get(entry.getValue());
+                if (message == null) {
+                    error("Invalid message key '" + entry.getValue() + "', expected one of these: " + messages.keySet());
+                }
+
+                //noinspection ConstantConditions
+                if (!showWarning(message, branchName)) {
+                    error("Push aborted.");
+                }
+            }
+        }
+    }
+
+    private static void error(String message) {
+        //noinspection UseOfSystemOutOrSystemErr
+        System.err.println(message);
+        System.exit(1);
+    }
+
+    private static boolean showWarning(String reason, String targetBranch) {
+        String baseMessage = "You are about to commit to '" + targetBranch + "',\n" +
+                             "and it is probably not the best idea.\n" +
+                             "Please think twice before pressing 'Yes'.";
+
+        String confirmationMessage = "Do you still want to commit to '" + targetBranch + "'?";
+
+        String completeMessage = baseMessage + "\n\nReason: " + reason.replace("\\n", "\n") + "\n\n" + confirmationMessage;
+
+        int result = JOptionPane.showOptionDialog(
+                null, completeMessage, "Friendly warning",
+                JOptionPane.YES_NO_OPTION, JOptionPane.WARNING_MESSAGE, null,
+                new String[] { "Yes", "No" }, "No");
+
+        return result == JOptionPane.YES_OPTION;
+    }
+
+    private static Map<String, String> getProperties(URL url) throws Exception {
+        URLConnection connection = url.openConnection();
+
+        try (InputStream is = connection.getInputStream()) {
+            Properties properties = new Properties();
+            properties.load(is);
+
+            Map<String, String> propertyMap = new HashMap<>();
+            for (Map.Entry<Object, Object> entry : properties.entrySet()) {
+                if (entry.getKey() instanceof String && entry.getValue() instanceof String) {
+                    propertyMap.put((String) entry.getKey(), (String) entry.getValue());
+                }
+            }
+
+            return propertyMap;
+        }
+    }
+}

settings.gradle

@@ -167,6 +167,7 @@ include ":kotlin-build-common",
         ":examples:scripting-jvm-maven-deps",
         ":examples:scripting-jvm-maven-deps-host",
         ":pill:generate-all-tests",
+        ":libraries:kotlin-prepush-hook",
         ":include:kotlin-compiler",
 
         // plugin markers:
@@ -276,6 +277,7 @@ project(':examples:scripting-jvm-maven-deps').projectDir = "$rootDir/libraries/e
 project(':examples:scripting-jvm-maven-deps-host').projectDir = "$rootDir/libraries/examples/scripting/jvm-maven-deps/host" as File
 project(':pill:generate-all-tests').projectDir = "$rootDir/plugins/pill/generate-all-tests" as File
 project(':kotlin-imports-dumper-compiler-plugin').projectDir = "$rootDir/plugins/imports-dumper" as File
+project(':libraries:kotlin-prepush-hook').projectDir = "$rootDir/libraries/tools/kotlin-prepush-hook" as File
 
 // plugin markers:
 project(':kotlin-gradle-plugin:plugin-marker').projectDir = file("$rootDir/libraries/tools/kotlin-gradle-plugin/plugin-marker")