Improve support for Bazel builds, towards #88

This commit adds a new Bazel build to this codebase so that Bazel users can
build the semanticdb-javac compiler plugin from source and use it in
their Bazel build. This commit includes examples of how a Bazel user
could potentially enable the compiler plugin dynamically based on a
command-line flag, but we don't know if this is the best way to
integrate lsif-java with a Bazel codebase.

This commit is just an incremental step towards Bazel support, it's not
a complete solution yet because the `lsif-java index-semanticdb` command
still needs additional functionality to read jar files from the
`bazel-bin` directory.

Author: olafurpg

.gitignore

@@ -56,3 +56,7 @@ dump.lsif
 
 ./generated
 /sources
+bazel-bin
+bazel-lsif-java
+bazel-out
+bazel-testlogs

WORKSPACE

@@ -0,0 +1,43 @@
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+##########
+# Protobuf
+##########
+http_archive(
+    name = "rules_proto",
+    sha256 = "66bfdf8782796239d3875d37e7de19b1d94301e8972b3cbd2446b332429b4df1",
+    strip_prefix = "rules_proto-4.0.0",
+    urls = [
+        "https://mirror.bazel.build/github.com/bazelbuild/rules_proto/archive/refs/tags/4.0.0.tar.gz",
+        "https://github.com/bazelbuild/rules_proto/archive/refs/tags/4.0.0.tar.gz",
+    ],
+)
+load("@rules_proto//proto:repositories.bzl", "rules_proto_dependencies", "rules_proto_toolchains")
+rules_proto_dependencies()
+rules_proto_toolchains()
+
+##############
+# JVM External
+##############
+RULES_JVM_EXTERNAL_TAG = "4.2"
+RULES_JVM_EXTERNAL_SHA = "cd1a77b7b02e8e008439ca76fd34f5b07aecb8c752961f9640dea15e9e5ba1ca"
+http_archive(
+    name = "rules_jvm_external",
+    strip_prefix = "rules_jvm_external-%s" % RULES_JVM_EXTERNAL_TAG,
+    sha256 = RULES_JVM_EXTERNAL_SHA,
+    url = "https://github.com/bazelbuild/rules_jvm_external/archive/%s.zip" % RULES_JVM_EXTERNAL_TAG,
+)
+load("@rules_jvm_external//:repositories.bzl", "rules_jvm_external_deps")
+rules_jvm_external_deps()
+load("@rules_jvm_external//:setup.bzl", "rules_jvm_external_setup")
+rules_jvm_external_setup()
+load("@rules_jvm_external//:defs.bzl", "maven_install")
+maven_install(
+    artifacts = [
+        "com.google.protobuf:protobuf-java:3.15.6",
+        "org.projectlombok:lombok:1.18.22",
+    ],
+    repositories = [
+         "https://repo1.maven.org/maven2",
+    ],
+)

lsif-semanticdb/src/main/protobuf/BUILD

@@ -0,0 +1,15 @@
+load("@rules_proto//proto:defs.bzl", "proto_library")
+load("@rules_java//java:defs.bzl", "java_proto_library")
+
+package(
+    default_visibility = ["//visibility:public"],
+)
+
+java_proto_library(
+	name = "lsif_java_proto",
+	deps = [":lsif_proto"],
+)
+proto_library(
+	name = "lsif_proto",
+	srcs = ["lsif.proto"]
+)

maven_install.json

@@ -0,0 +1,33 @@
+{
+    "dependency_tree": {
+        "__AUTOGENERATED_FILE_DO_NOT_MODIFY_THIS_FILE_MANUALLY": "THERE_IS_NO_DATA_ONLY_ZUUL",
+        "__INPUT_ARTIFACTS_HASH": -1430904333,
+        "__RESOLVED_ARTIFACTS_HASH": 2127018902,
+        "conflict_resolution": {},
+        "dependencies": [
+            {
+                "coord": "com.google.protobuf:protobuf-java:3.15.6",
+                "dependencies": [],
+                "directDependencies": [],
+                "file": "v1/https/repo1.maven.org/maven2/com/google/protobuf/protobuf-java/3.15.6/protobuf-java-3.15.6.jar",
+                "mirror_urls": [
+                    "https://repo1.maven.org/maven2/com/google/protobuf/protobuf-java/3.15.6/protobuf-java-3.15.6.jar"
+                ],
+                "sha256": "97a2b7dbcd9a81a9760c1531ee0b7253a4633e9f9fc5accfb66c4205d23c30c6",
+                "url": "https://repo1.maven.org/maven2/com/google/protobuf/protobuf-java/3.15.6/protobuf-java-3.15.6.jar"
+            },
+            {
+                "coord": "org.projectlombok:lombok:1.18.22",
+                "dependencies": [],
+                "directDependencies": [],
+                "file": "v1/https/repo1.maven.org/maven2/org/projectlombok/lombok/1.18.22/lombok-1.18.22.jar",
+                "mirror_urls": [
+                    "https://repo1.maven.org/maven2/org/projectlombok/lombok/1.18.22/lombok-1.18.22.jar"
+                ],
+                "sha256": "ecef1581411d7a82cc04281667ee0bac5d7c0a5aae74cfc38430396c91c31831",
+                "url": "https://repo1.maven.org/maven2/org/projectlombok/lombok/1.18.22/lombok-1.18.22.jar"
+            }
+        ],
+        "version": "0.1.0"
+    }
+}

semanticdb-java/src/main/java/com/sourcegraph/semanticdb_javac/BUILD

@@ -0,0 +1,12 @@
+load("@rules_java//java:defs.bzl", "java_library")
+package(
+    default_visibility = ["//visibility:public"],
+)
+
+java_library(
+	name = "semanticdb_java",
+	srcs = glob(["*.java"]),
+	deps = [
+		"//semanticdb-java/src/main/protobuf:semanticdb_java_proto",
+	],
+)

semanticdb-java/src/main/protobuf/BUILD

@@ -0,0 +1,16 @@
+load("@rules_java//java:defs.bzl", "java_proto_library")
+load("@rules_proto//proto:defs.bzl", "proto_library")
+
+package(
+    default_visibility = ["//visibility:public"],
+)
+
+java_proto_library(
+	name = "semanticdb_java_proto",
+	deps = [":semanticdb_proto"],
+)
+
+proto_library(
+	name = "semanticdb_proto",
+	srcs = ["semanticdb.proto"]
+)

semanticdb-javac/BUILD

@@ -0,0 +1,41 @@
+load("@bazel_skylib//rules:common_settings.bzl", "string_flag")
+load("@rules_java//java:defs.bzl", "java_import", "java_library", "java_plugin")
+
+package(
+    default_visibility = ["//visibility:public"],
+)
+
+config_setting(
+    name = "is_enabled",
+    flag_values = {":enabled": "true"},
+)
+
+string_flag(
+    name = "enabled",
+    values = ["true", "false"],
+    build_setting_default = "false",
+)
+
+java_import(
+    name = "javac-import",
+    jars = ["@bazel_tools//third_party/java/jdk/langtools:javac_jar"],
+)
+
+java_plugin(
+	name = "plugin",
+	deps = [
+		":semanticdb-javac",
+	],
+)
+
+
+java_library(
+	name = "semanticdb-javac",
+	srcs = glob(["src/main/java/**/*.java"]),
+	resources = ["src/main/resources/META-INF/services/com.sun.source.util.Plugin"],
+	deps = [
+		"//semanticdb-java/src/main/protobuf:semanticdb_java_proto",
+		"//semanticdb-java/src/main/java/com/sourcegraph/semanticdb_javac:semanticdb_java",
+		":javac-import",
+	],
+)

semanticdb-javac/defs.bzl

@@ -0,0 +1,27 @@
+"""Java rules that automatically register the SemanticDB compiler plugin based on the presence of a string flag."""
+load("@rules_java//java:defs.bzl", native_java_library="java_library", native_java_binary="java_binary")
+
+def java_library(javacopts=[], plugins=[],**kwargs):
+    native_java_library(
+	    javacopts=_actual_javacopts(javacopts),
+	    plugins=_actual_plugins(plugins),
+	    **kwargs)
+
+
+def java_binary(javacopts=[], plugins=[],**kwargs):
+    native_java_binary(
+	    javacopts=_actual_javacopts(javacopts),
+	    plugins=_actual_plugins(plugins),
+	    **kwargs)
+
+def _actual_javacopts(javacopts):
+    return select({
+        "//semanticdb-javac:is_enabled": ["'-Xplugin:semanticdb -build-tool:bazel'"] + javacopts,
+        "//conditions:default": javacopts,
+    })
+
+def _actual_plugins(plugins):
+    return select({
+        "//semanticdb-javac:is_enabled": ["//semanticdb-javac:plugin"] + plugins,
+        "//conditions:default": plugins,
+    })

semanticdb-javac/src/main/java/com/sourcegraph/semanticdb_javac/SemanticdbJavacOptions.java

@@ -23,6 +23,7 @@ public class SemanticdbJavacOptions {
   public boolean includeText = false;
   public boolean verboseEnabled = false;
   public final ArrayList<String> errors;
+  public boolean isErrorReported = false;
   public UriScheme uriScheme = UriScheme.DEFAULT;
 
   public static String stubClassName = "META-INF-semanticdb-stub";
@@ -56,6 +57,10 @@ public static SemanticdbJavacOptions parse(String[] args, Context ctx) {
         result.sourceroot = Paths.get(arg.substring("-sourceroot:".length())).normalize();
       } else if (arg.equals("-build-tool:sbt")) {
         result.uriScheme = UriScheme.SBT;
+      } else if (arg.equals("-build-tool:bazel")) {
+        result.uriScheme = UriScheme.BAZEL;
+        useJavacClassesDir = true;
+        result.targetroot = getJavacClassesDir(result, ctx);
       } else if (arg.equals("-text:on")) {
         result.includeText = true;
       } else if (arg.equals("-text:off")) {
@@ -73,7 +78,11 @@ public static SemanticdbJavacOptions parse(String[] args, Context ctx) {
     if (result.targetroot == null && !useJavacClassesDir) {
       result.errors.add(missingRequiredDirectoryOption("targetroot"));
     }
-    if (result.sourceroot == null) {
+    if (result.uriScheme != UriScheme.BAZEL && result.sourceroot == null) {
+      // When using -build-tool:bazel, the sourceroot is automatically inferred from the first
+      // compilation unit.
+      // See `SemanticdbTaskListener.inferBazelSourceroot()` for the method that infers the
+      // sourceroot.
       result.errors.add(missingRequiredDirectoryOption("sourceroot"));
     }
     return result;

semanticdb-javac/src/main/java/com/sourcegraph/semanticdb_javac/SemanticdbPlugin.java

@@ -1,10 +1,10 @@
 package com.sourcegraph.semanticdb_javac;
 
-import com.sun.source.util.JavacTask;
-import com.sun.source.util.Plugin;
+import com.sun.source.util.*;
 import com.sun.tools.javac.api.BasicJavacTask;
 import com.sun.tools.javac.model.JavacTypes;
 import com.sun.tools.javac.util.Context;
+import com.sun.tools.javac.util.Options;
 
 /** Entrypoint of the semanticdb-javac compiler plugin. */
 public class SemanticdbPlugin implements Plugin {
@@ -18,17 +18,10 @@ public String getName() {
   public void init(JavacTask task, String... args) {
     Context ctx = ((BasicJavacTask) task).getContext();
 
-    SemanticdbReporter reporter = new SemanticdbReporter();
+    SemanticdbReporter reporter = new SemanticdbReporter(Trees.instance(task));
     SemanticdbJavacOptions options = SemanticdbJavacOptions.parse(args, ctx);
     GlobalSymbolsCache globals = new GlobalSymbolsCache(options);
     JavacTypes javacTypes = JavacTypes.instance(ctx);
-    if (!options.errors.isEmpty()) {
-      for (String error : options.errors) {
-        reporter.error(error);
-      }
-    } else {
-      task.addTaskListener(
-          new SemanticdbTaskListener(options, task, globals, reporter, javacTypes));
-    }
+    task.addTaskListener(new SemanticdbTaskListener(options, task, globals, reporter, javacTypes));
   }
 }