Reanalyze after creating a referenced part.

We need to finish linking CompilationUnitElement(s) to LibraryElement(s)
even for not existing sources. Otherwise we get NPE later and leave
model in the ERROR state.

R=brianwilkerson@google.com
BUG=

Review URL: https://codereview.chromium.org//1168743002

pkg/analyzer/lib/src/context/cache.dart

@@ -425,6 +425,15 @@ class CacheEntry {
    */
   /*<V>*/ void setValue(ResultDescriptor /*<V>*/ descriptor, dynamic /*V*/
       value, List<TargetedResult> dependedOn) {
+//    {
+//      String valueStr = '$value';
+//      if (valueStr.length > 20) {
+//        valueStr = valueStr.substring(0, 20) + '...';
+//      }
+//      valueStr = valueStr.replaceAll('\n', '\\n');
+//      print(
+//          'setValue $descriptor for $target value=$valueStr deps=$dependedOn');
+//    }
     _validateStateChange(descriptor, CacheState.VALID);
     TargetedResult thisResult = new TargetedResult(target, descriptor);
     if (_partition != null) {
@@ -464,6 +473,7 @@ class CacheEntry {
    * invalidation to other results that depend on it.
    */
   void _invalidate(ResultDescriptor descriptor) {
+//    print('invalidate $descriptor for $target');
     ResultData thisData = _resultMap.remove(descriptor);
     if (thisData == null) {
       return;

pkg/analyzer/lib/src/task/dart.dart

@@ -1331,7 +1331,7 @@ class BuildLibraryElementTask extends SourceBasedAnalysisTask {
         Source partSource = partDirective.source;
         hasPartDirective = true;
         CompilationUnit partUnit = partUnitMap[partSource];
-        if (partUnit != null && context.exists(partSource)) {
+        if (partUnit != null) {
           CompilationUnitElementImpl partElement = partUnit.element;
           partElement.uriOffset = partUri.offset;
           partElement.uriEnd = partUri.end;
@@ -1340,24 +1340,26 @@ class BuildLibraryElementTask extends SourceBasedAnalysisTask {
           // Validate that the part contains a part-of directive with the same
           // name as the library.
           //
-          String partLibraryName =
-              _getPartLibraryName(partSource, partUnit, directivesToResolve);
-          if (partLibraryName == null) {
-            errors.add(new AnalysisError(librarySource, partUri.offset,
-                partUri.length, CompileTimeErrorCode.PART_OF_NON_PART,
-                [partUri.toSource()]));
-          } else if (libraryNameNode == null) {
-            if (partsLibraryName == _UNKNOWN_LIBRARY_NAME) {
-              partsLibraryName = partLibraryName;
-            } else if (partsLibraryName != partLibraryName) {
-              partsLibraryName = null;
+          if (context.exists(partSource)) {
+            String partLibraryName =
+                _getPartLibraryName(partSource, partUnit, directivesToResolve);
+            if (partLibraryName == null) {
+              errors.add(new AnalysisError(librarySource, partUri.offset,
+                  partUri.length, CompileTimeErrorCode.PART_OF_NON_PART,
+                  [partUri.toSource()]));
+            } else if (libraryNameNode == null) {
+              if (partsLibraryName == _UNKNOWN_LIBRARY_NAME) {
+                partsLibraryName = partLibraryName;
+              } else if (partsLibraryName != partLibraryName) {
+                partsLibraryName = null;
+              }
+            } else if (libraryNameNode.name != partLibraryName) {
+              errors.add(new AnalysisError(librarySource, partUri.offset,
+                  partUri.length, StaticWarningCode.PART_OF_DIFFERENT_LIBRARY, [
+                libraryNameNode.name,
+                partLibraryName
+              ]));
             }
-          } else if (libraryNameNode.name != partLibraryName) {
-            errors.add(new AnalysisError(librarySource, partUri.offset,
-                partUri.length, StaticWarningCode.PART_OF_DIFFERENT_LIBRARY, [
-              libraryNameNode.name,
-              partLibraryName
-            ]));
           }
           if (entryPoint == null) {
             entryPoint = _findEntryPoint(partElement);

pkg/analyzer/lib/src/task/driver.dart

@@ -126,6 +126,7 @@ class AnalysisDriver {
       }
       // Create a new WorkOrder.
       TargetedResult request = highestManager.getNextResult();
+//      print('request: $request');
       if (request != null) {
         WorkOrder workOrder =
             createWorkOrderForResult(request.target, request.result);

pkg/analyzer/test/src/context/context_test.dart

@@ -473,6 +473,8 @@ library lib;
 part 'part.dart';''');
     // run all tasks without part
     _analyzeAll_assertFinished();
+    expect(_hasAnalysisErrorWithErrorSeverity(context.getErrors(libSource)),
+        isTrue, reason: "lib has errors");
     // add part and run all tasks
     Source partSource = addSource("/part.dart", r'''
 part of lib;
@@ -481,6 +483,11 @@ part of lib;
     // "libSource" should be here
     List<Source> librariesWithPart = context.getLibrariesContaining(partSource);
     expect(librariesWithPart, unorderedEquals([libSource]));
+    expect(_hasAnalysisErrorWithErrorSeverity(context.getErrors(libSource)),
+        isFalse, reason: "lib doesn't have errors");
+    expect(
+        context.getResolvedCompilationUnit2(partSource, libSource), isNotNull,
+        reason: "part resolved");
   }
 
   void test_performAnalysisTask_changeLibraryContents() {

pkg/analyzer/test/src/task/dart_test.dart

@@ -981,7 +981,12 @@ library lib;
 part 'no-such-file.dart';
 '''
     });
-    expect(libraryElement.parts, isEmpty);
+    expect(libraryElement.parts, hasLength(1));
+    CompilationUnitElement part = libraryElement.parts[0];
+    expect(part, isNotNull);
+    expect(part.source, isNotNull);
+    expect(part.library, same(libraryElement));
+    expect(context.exists(part.source), isFalse);
   }
 
   test_perform_patchTopLevelAccessors() {