Support Bzlmod (MODULE.bazel) and fix test compilation

scripts/build.sh

@@ -29,6 +29,9 @@ if [ ! -e src/main/java/com/google/devtools/build/lib/analysis/AnalysisProtos.ja
     ./scripts/gen_proto.sh
 fi
 
+export JAVA_HOME=$(pwd)/jdks/linux/jdk-21
+export PATH=$JAVA_HOME/bin:$PATH
+
 mvn package -DskipTests
 
 # Build vsix

src/main/java/org/javacs/InferConfig.java

@@ -100,16 +100,20 @@ Set<Path> classPath() {
 
         // Bazel
         var bazelWorkspaceRoot = bazelWorkspaceRoot();
-        if (Files.exists(bazelWorkspaceRoot.resolve("WORKSPACE"))) {
+        if (isBazelProject(bazelWorkspaceRoot)) {
             return bazelClasspath(bazelWorkspaceRoot);
         }
 
         return Collections.emptySet();
     }
 
-    private Path bazelWorkspaceRoot() {
+    boolean isBazelProject(Path root) {
+        return Files.exists(root.resolve("WORKSPACE")) || Files.exists(root.resolve("MODULE.bazel"));
+    }
+
+    Path bazelWorkspaceRoot() {
         for (var current = workspaceRoot; current != null; current = current.getParent()) {
-            if (Files.exists(current.resolve("WORKSPACE"))) {
+            if (isBazelProject(current)) {
                 return current;
             }
         }
@@ -141,7 +145,7 @@ Set<Path> buildDocPath() {
 
         // Bazel
         var bazelWorkspaceRoot = bazelWorkspaceRoot();
-        if (Files.exists(bazelWorkspaceRoot.resolve("WORKSPACE"))) {
+        if (isBazelProject(bazelWorkspaceRoot)) {
             return bazelSourcepath(bazelWorkspaceRoot);
         }
 

src/main/java/org/javacs/JavaLanguageServer.java

@@ -210,7 +210,7 @@ public InitializeResult initialize(InitializeParams params) {
     }
 
     private static final String[] watchFiles = {
-        "**/*.java", "**/pom.xml", "**/BUILD", "**/javaconfig.json", "**/WORKSPACE"
+        "**/*.java", "**/pom.xml", "**/BUILD", "**/javaconfig.json", "**/WORKSPACE", "**/MODULE.bazel"
     };
 
     @Override
@@ -275,6 +275,8 @@ public void didChangeWatchedFiles(DidChangeWatchedFilesParams params) {
             switch (name) {
                 case "BUILD":
                 case "pom.xml":
+                case "WORKSPACE":
+                case "MODULE.bazel":
                     LOG.info("Compiler needs to be re-created because " + file + " has changed");
                     modifiedBuild = true;
             }

src/test/java/org/javacs/HoverTest.java

@@ -3,6 +3,7 @@
 import static org.hamcrest.Matchers.*;
 import static org.hamcrest.MatcherAssert.assertThat;
 
+import java.util.List;
 import java.util.StringJoiner;
 import org.javacs.lsp.*;
 import org.junit.Test;
@@ -78,8 +79,12 @@ private String symbolAt(String file, int line, int character) {
         var pos =
                 new TextDocumentPositionParams(
                         new TextDocumentIdentifier(FindResource.uri(file)), new Position(line - 1, character - 1));
+        var hover = server.hover(pos).get();
+        if (hover.contents instanceof MarkupContent) {
+            return ((MarkupContent) hover.contents).value;
+        }
         var result = new StringJoiner("\n");
-        for (var h : server.hover(pos).get().contents) {
+        for (var h : (List<MarkedString>) hover.contents) {
             result.add(h.value);
         }
         return result.toString();

src/test/java/org/javacs/InferBazelBzlmodConfigTest.java

@@ -0,0 +1,43 @@
+package org.javacs;
+
+import static org.hamcrest.Matchers.*;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+import java.nio.file.Paths;
+import java.nio.file.Files;
+import org.junit.Test;
+import org.junit.BeforeClass;
+import java.io.IOException;
+
+public class InferBazelBzlmodConfigTest {
+    private static final String EXAMPLE_PATH = "src/test/examples/bazel-bzlmod-project";
+
+    @BeforeClass
+    public static void setup() throws IOException {
+        var path = Paths.get(EXAMPLE_PATH);
+        if (!Files.exists(path)) {
+            Files.createDirectories(path);
+        }
+        var moduleFile = path.resolve("MODULE.bazel");
+        if (!Files.exists(moduleFile)) {
+            Files.createFile(moduleFile);
+        }
+        var subDir = path.resolve("subdir");
+        if (!Files.exists(subDir)) {
+            Files.createDirectories(subDir);
+        }
+    }
+
+    @Test
+    public void detectBzlmodRoot() {
+        var config = new InferConfig(Paths.get(EXAMPLE_PATH));
+        assertThat(config.isBazelProject(Paths.get(EXAMPLE_PATH)), is(true));
+        assertThat(config.bazelWorkspaceRoot(), equalTo(Paths.get(EXAMPLE_PATH)));
+    }
+
+    @Test
+    public void detectBzlmodRootFromSubdir() {
+        var config = new InferConfig(Paths.get(EXAMPLE_PATH).resolve("subdir"));
+        assertThat(config.bazelWorkspaceRoot(), equalTo(Paths.get(EXAMPLE_PATH)));
+    }
+}