From a103007b8310f1e0dc7e70e6eaee7c2fc6d556bf Mon Sep 17 00:00:00 2001
From: Sam Snyder <sam@moderne.io>
Date: Thu, 10 Feb 2022 17:05:49 -0800
Subject: [PATCH] Add autodetection of Java styles

---
 pom.xml                                       |  2 +-
 .../maven/MavenMojoProjectParser.java         | 27 +++++++++++++++++--
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/pom.xml b/pom.xml
index f55d551e..946f0e60 100644
--- a/pom.xml
+++ b/pom.xml
@@ -40,7 +40,7 @@
     </scm>
 
     <properties>
-        <rewrite.version>7.18.0</rewrite.version>
+        <rewrite.version>7.18.1</rewrite.version>
 
         <!-- using 'ssh' url scheme by default, which assumes a human is performing git operations leveraging an ssh key -->
         <developerConnectionUrl>scm:git:ssh://git@github.com/openrewrite/rewrite-maven-plugin.git</developerConnectionUrl>
diff --git a/src/main/java/org/openrewrite/maven/MavenMojoProjectParser.java b/src/main/java/org/openrewrite/maven/MavenMojoProjectParser.java
index f32bc8a4..2e009324 100644
--- a/src/main/java/org/openrewrite/maven/MavenMojoProjectParser.java
+++ b/src/main/java/org/openrewrite/maven/MavenMojoProjectParser.java
@@ -21,6 +21,10 @@
 import org.openrewrite.java.JavaParser;
 import org.openrewrite.java.marker.JavaProject;
 import org.openrewrite.java.marker.JavaVersion;
+import org.openrewrite.java.style.Autodetect;
+import org.openrewrite.java.style.ImportLayoutStyle;
+import org.openrewrite.java.style.SpacesStyle;
+import org.openrewrite.java.style.TabsAndIndentsStyle;
 import org.openrewrite.java.tree.J;
 import org.openrewrite.marker.BuildTool;
 import org.openrewrite.marker.Generated;
@@ -48,6 +52,7 @@
 import static java.util.Collections.emptyList;
 import static java.util.stream.Collectors.toList;
 import static org.openrewrite.Tree.randomId;
+import static org.openrewrite.internal.ListUtils.map;
 
 // -----------------------------------------------------------------------------------------------------------------
 // Notes About Provenance Information:
@@ -308,7 +313,7 @@ public List<SourceFile> listSourceFiles(Iterable<NamedStyles> styles,
 
         // JavaParser will add SourceSet Markers to any Java SourceFile, so only adding the project provenance info to
         // java source.
-        sourceFiles.addAll(ListUtils.map(javaParser.parse(mainJavaSources, baseDir, ctx),
+        sourceFiles.addAll(ListUtils.map(maybeAutodetectStyles(javaParser.parse(mainJavaSources, baseDir, ctx), styles),
                 addProvenance(baseDir, projectProvenance, generatedSourcePaths)));
 
         ResourceParser rp = new ResourceParser(logger, exclusions, sizeThresholdMb);
@@ -330,7 +335,7 @@ public List<SourceFile> listSourceFiles(Iterable<NamedStyles> styles,
         // JavaParser will add SourceSet Markers to any Java SourceFile, so only adding the project provenance info to
         // java source.
         sourceFiles.addAll(ListUtils.map(
-                javaParser.parse(listJavaSources(mavenProject.getBuild().getTestSourceDirectory()), baseDir, ctx),
+                maybeAutodetectStyles(javaParser.parse(listJavaSources(mavenProject.getBuild().getTestSourceDirectory()), baseDir, ctx), styles),
                 addProvenance(baseDir, projectProvenance, null)));
 
         // Any resources parsed from "test/resources" should also have the test source set added to them.
@@ -347,6 +352,24 @@ public List<SourceFile> listSourceFiles(Iterable<NamedStyles> styles,
         return sourceFiles;
     }
 
+    private List<J.CompilationUnit> maybeAutodetectStyles(List<J.CompilationUnit> sourceFiles, @Nullable Iterable<NamedStyles> styles) {
+        if (styles != null) {
+            return sourceFiles;
+        }
+        Autodetect autodetect = Autodetect.detect(sourceFiles);
+
+        Collection<NamedStyles> namedStyles = Collections.singletonList(autodetect);
+
+        ImportLayoutStyle importLayout = NamedStyles.merge(ImportLayoutStyle.class, namedStyles);
+        SpacesStyle spacesStyle = NamedStyles.merge(SpacesStyle.class, namedStyles);
+        TabsAndIndentsStyle tabsStyle = NamedStyles.merge(TabsAndIndentsStyle.class, namedStyles);
+
+        return map(sourceFiles, cu -> {
+            List<Marker> markers = ListUtils.concat(map(cu.getMarkers().getMarkers(), m -> m instanceof NamedStyles ? null : m), autodetect);
+            return cu.withMarkers(cu.getMarkers().withMarkers(markers));
+        });
+    }
+
     private static <S extends SourceFile> UnaryOperator<S> addProvenance(Path baseDir, List<Marker> provenance, @Nullable Collection<Path> generatedSources) {
         return s -> {
             for (Marker marker : provenance) {