Rebuild only if proto changed.

compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/kotlin/incremental/IncrementalCache.kt

@@ -29,6 +29,7 @@ import org.jetbrains.jet.lang.resolve.kotlin.VirtualFileKotlinClass
 import org.jetbrains.jet.lang.resolve.kotlin.header.KotlinClassHeader
 import org.jetbrains.jet.descriptors.serialization.BitEncoding
 import org.jetbrains.jet.utils.intellij.*
+import java.util.Arrays
 
 public class IncrementalCache(baseDir: File) {
     class object {
@@ -72,17 +73,26 @@ public class IncrementalCache(baseDir: File) {
         })
     }
 
-    public fun saveFileToCache(moduleId: String, file: File) {
+    public fun saveFileToCache(moduleId: String, file: File): Boolean {
         val classNameAndHeader = VirtualFileKotlinClass.readClassNameAndHeader(file.readBytes())
-        if (classNameAndHeader == null) return
+        if (classNameAndHeader == null) return false
 
         val (className, header) = classNameAndHeader
         if (header.kind == KotlinClassHeader.Kind.PACKAGE_FACADE) {
-            putPackageData(moduleId, className.getFqNameForClassNameWithoutDollars().parent(), BitEncoding.decodeBytes(header.annotationData!!))
+            val fqName = className.getFqNameForClassNameWithoutDollars().parent()
+            val data = BitEncoding.decodeBytes(header.annotationData!!)
+            val oldData = getPackageData(moduleId, fqName)
+            if (Arrays.equals(data, oldData)) {
+                return false
+            }
+            putPackageData(moduleId, fqName, data)
+            return true
         }
+        // TODO Check class signatures, too!
+        return false
     }
 
-    public fun putPackageData(moduleId: String, fqName: FqName, data: ByteArray) {
+    private fun putPackageData(moduleId: String, fqName: FqName, data: ByteArray) {
         packageFacadeData.put(PackageFacadeId(moduleId, fqName), data)
     }
 

jps-plugin/src/org/jetbrains/jet/jps/build/KotlinBuilder.java

@@ -198,6 +198,8 @@ public class KotlinBuilder extends ModuleLevelBuilder {
         IncrementalCache cache = new IncrementalCache(KotlinBuilderModuleScriptGenerator.getIncrementalCacheDir(context));
 
         try {
+            boolean significantChanges = false;
+
             for (SimpleOutputItem outputItem : outputItemCollector.getOutputs()) {
                 BuildTarget<?> target = null;
                 Collection<File> sourceFiles = outputItem.getSourceFiles();
@@ -215,7 +217,9 @@ public class KotlinBuilder extends ModuleLevelBuilder {
                 File outputFile = outputItem.getOutputFile();
 
                 if (IncrementalCompilation.ENABLED) {
-                    cache.saveFileToCache(target.getId(), outputFile);
+                    if (cache.saveFileToCache(target.getId(), outputFile)) {
+                        significantChanges = true;
+                    }
                 }
 
                 outputConsumer.registerOutputFile(target, outputFile, paths(sourceFiles));
@@ -223,18 +227,21 @@ public class KotlinBuilder extends ModuleLevelBuilder {
 
             if (IncrementalCompilation.ENABLED) {
                 // TODO should mark dependencies as dirty, as well
-                FSOperations.markDirty(context, chunk, new FileFilter() {
+                if (significantChanges) {
-                    @Override
+                    FSOperations.markDirty(context, chunk, new FileFilter() {
-                    public boolean accept(@NotNull File file) {
+                        @Override
-                        return !allCompiledFiles.contains(file);
+                        public boolean accept(@NotNull File file) {
-                    }
+                            return !allCompiledFiles.contains(file);
-                });
+                        }
+                    });
+                }
                 return ExitCode.ADDITIONAL_PASS_REQUIRED;
             }
             else {
                 return ExitCode.OK;
             }
-        } finally {
+        }
+        finally {
             cache.close();
         }
     }

jps-plugin/test/org/jetbrains/jet/jps/build/IncrementalJpsTest.kt

@@ -108,6 +108,14 @@ public class IncrementalJpsTest : JpsBuildTestCase() {
         doTest()
     }
 
+    fun testReturnTypeChanged() {
+        doTest()
+    }
+
+    fun testTopLevelFunctionSameSignature() {
+        doTest()
+    }
+
     private class MyLogger(val rootPath: String) : ProjectBuilderLoggerBase() {
         private val logBuf = StringBuilder()
         public val log: String

jps-plugin/testData/incremental/independentClasses/build.log

@@ -4,9 +4,3 @@ End of files
 Compiling files:
 src/Foo.kt
 End of files
-Cleaning output files:
-out/production/module/test/Bar.class
-End of files
-Compiling files:
-src/Bar.kt
-End of files

jps-plugin/testData/incremental/returnTypeChanged/build.log

@@ -0,0 +1,14 @@
+Cleaning output files:
+out/production/module/test/TestPackage-fun-*.class
+out/production/module/test/TestPackage.class
+End of files
+Compiling files:
+src/fun.kt
+End of files
+Cleaning output files:
+out/production/module/test/TestPackage-usage-*.class
+out/production/module/test/TestPackage.class
+End of files
+Compiling files:
+src/usage.kt
+End of files

jps-plugin/testData/incremental/returnTypeChanged/fun.kt

@@ -0,0 +1,4 @@
+package test
+
+fun foo() {
+}

jps-plugin/testData/incremental/returnTypeChanged/fun.kt.new

@@ -0,0 +1,3 @@
+package test
+
+fun foo(): String = ":)"

jps-plugin/testData/incremental/returnTypeChanged/usage.kt

@@ -0,0 +1,5 @@
+package test
+
+fun usage() {
+    foo()
+}

jps-plugin/testData/incremental/simpleClassDependency/build.log

@@ -5,9 +5,3 @@ End of files
 Compiling files:
 src/Foo.kt
 End of files
-Cleaning output files:
-out/production/module/test/Bar.class
-End of files
-Compiling files:
-src/Bar.kt
-End of files

jps-plugin/testData/incremental/topLevelFunctionSameSignature/build.log

@@ -0,0 +1,7 @@
+Cleaning output files:
+out/production/module/test/TestPackage-fun-*.class
+out/production/module/test/TestPackage.class
+End of files
+Compiling files:
+src/fun.kt
+End of files

jps-plugin/testData/incremental/topLevelFunctionSameSignature/fun.kt

@@ -0,0 +1,4 @@
+package test
+
+fun foo() {
+}

jps-plugin/testData/incremental/topLevelFunctionSameSignature/fun.kt.new

@@ -0,0 +1,5 @@
+package test
+
+fun foo() {
+    println("body is changed, but it doesn't matter, we won't rebuild dependencies")
+}

jps-plugin/testData/incremental/topLevelFunctionSameSignature/usage.kt

@@ -0,0 +1,5 @@
+package test
+
+fun usage() {
+    foo()
+}

jps-plugin/testData/incremental/topLevelMembersInTwoPackages/build.log

@@ -5,10 +5,3 @@ End of files
 Compiling files:
 src/a.kt
 End of files
-Cleaning output files:
-out/production/module/test/TestPackage-b-*.class
-out/production/module/test/TestPackage.class
-End of files
-Compiling files:
-src/b.kt
-End of files