Avoid calling parsers when there are no source files

With empty lists of main or test, Java or Kotlin files avoid invoking the parsers completely. That's more performant and avoids any bad side effects during initialization of the parsers. Fixes #658.
openrewrite · Nov 16, 2023 · 6d4255f · 6d4255f
1 parent 18501f9
commit 6d4255f
Showing 1 changed file with 12 additions and 12 deletions.
diff --git a/src/main/java/org/openrewrite/maven/MavenMojoProjectParser.java b/src/main/java/org/openrewrite/maven/MavenMojoProjectParser.java
@@ -323,13 +323,13 @@ private Stream<SourceFile> processMainSources(
         javaParserBuilder.classpath(dependencies).typeCache(typeCache);
         kotlinParserBuilder.classpath(dependencies).typeCache(new JavaTypeCache());
 
-        Stream<? extends SourceFile> cus = Stream.of(javaParserBuilder)
-                .map(JavaParser.Builder::build)
-                .flatMap(parser -> parser.parse(mainJavaSources, baseDir, ctx));
+        Stream<? extends SourceFile> cus = mainJavaSources.isEmpty() ? Stream.empty()
+                : Stream.of(javaParserBuilder).map(JavaParser.Builder::build)
+                        .flatMap(parser -> parser.parse(mainJavaSources, baseDir, ctx));
 
-        Stream<? extends SourceFile> kcus = Stream.of(kotlinParserBuilder)
-                .map(KotlinParser.Builder::build)
-                .flatMap(parser -> parser.parse(mainKotlinSources, baseDir, ctx));
+        Stream<? extends SourceFile> kcus = mainKotlinSources.isEmpty() ? Stream.empty()
+                : Stream.of(kotlinParserBuilder).map(KotlinParser.Builder::build)
+                        .flatMap(parser -> parser.parse(mainKotlinSources, baseDir, ctx));
 
         List<Marker> mainProjectProvenance = new ArrayList<>(projectProvenance);
         mainProjectProvenance.add(sourceSet("main", dependencies, typeCache));
@@ -382,13 +382,13 @@ private Stream<SourceFile> processTestSources(
 
         alreadyParsed.addAll(testKotlinSources);
 
-        Stream<? extends SourceFile> cus = Stream.of(javaParserBuilder)
-                .map(JavaParser.Builder::build)
-                .flatMap(parser -> parser.parse(testJavaSources, baseDir, ctx));
+        Stream<? extends SourceFile> cus = testJavaSources.isEmpty() ? Stream.empty()
+                : Stream.of(javaParserBuilder).map(JavaParser.Builder::build)
+                        .flatMap(parser -> parser.parse(testJavaSources, baseDir, ctx));
 
-        Stream<? extends SourceFile> kcus = Stream.of(kotlinParserBuilder)
-                .map(KotlinParser.Builder::build)
-                .flatMap(parser -> parser.parse(testKotlinSources, baseDir, ctx));
+        Stream<? extends SourceFile> kcus = testKotlinSources.isEmpty() ? Stream.empty()
+                : Stream.of(kotlinParserBuilder).map(KotlinParser.Builder::build)
+                        .flatMap(parser -> parser.parse(testKotlinSources, baseDir, ctx));
 
         List<Marker> markers = new ArrayList<>(projectProvenance);
         markers.add(sourceSet("test", testDependencies, typeCache));