Fix source map generation in BaseTranspiler.

There's some spooky action going on in Compiler#toSource that populates the source map that had already been returned from compile(). So we need to call toSource() before SourceMap#appendTo. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=141129216
google · Dec 6, 2016 · 72cd039 · 72cd039
1 parent 0c4173c
commit 72cd039
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Showing 2 changed files with 8 additions and 5 deletions.
diff --git a/src/com/google/javascript/jscomp/transpile/BaseTranspiler.java b/src/com/google/javascript/jscomp/transpile/BaseTranspiler.java
@@ -88,6 +88,7 @@ public static class CompilerSupplier {
     public CompileResult compile(String path, String code) {
       Compiler compiler = compiler();
       Result result = compiler.compile(EXTERNS, SourceFile.fromCode(path, code), options());
+      String source = compiler.toSource();
       StringBuilder sourceMap = new StringBuilder();
       if (result.sourceMap != null) {
         try {
@@ -96,11 +97,12 @@ public CompileResult compile(String path, String code) {
           // impossible, and not a big deal even if it did happen.
         }
       }
+      boolean transpiled = !result.transpiledFiles.isEmpty();
       return new CompileResult(
-          compiler.toSource(),
+          source,
           result.errors,
-          !result.transpiledFiles.isEmpty(),
-          sourceMap.toString());
+          transpiled,
+          transpiled ? sourceMap.toString() : "");
     }
 
     public String runtime(String library) {

diff --git a/test/com/google/javascript/jscomp/transpile/BaseTranspilerTest.java b/test/com/google/javascript/jscomp/transpile/BaseTranspilerTest.java
@@ -70,15 +70,16 @@ public void testCompilerSupplier_compileChanged() {
     assertThat(result.source).isEqualTo("var x = function() {\n  return 42;\n};\n");
     assertThat(result.errors).isEmpty();
     assertThat(result.transpiled).isTrue();
-    assertThat(result.sourceMap).contains("\"mappings\":\";\"");
+    assertThat(result.sourceMap)
+        .contains("\"mappings\":\"AAAA,IAAMA,IAAIA,QAAA,EAAM;AAAA,SAAA,EAAA;AAAA,CAAhB;;\"");
   }
 
   public void testCompilerSupplier_compileNoChange() {
     BaseTranspiler.CompileResult result = compiler.compile("source.js", "var x = 42;");
     assertThat(result.source).isEqualTo("var x = 42;\n");
     assertThat(result.errors).isEmpty();
     assertThat(result.transpiled).isFalse();
-    assertThat(result.sourceMap).contains("\"mappings\":\";\"");
+    assertThat(result.sourceMap).isEmpty();
   }
 
   public void testCompilerSupplier_runtime() {