Update TestErrorReporter to deduplicate identical errors

PiperOrigin-RevId: 722805984

Author: Closure Team

src/com/google/javascript/rhino/testing/TestErrorReporter.java

@@ -44,24 +44,28 @@
 import com.google.javascript.rhino.ErrorReporter;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.LinkedHashMap;
 
 /**
  * An error reporter for testing that verifies that messages reported to the reporter are expected.
  */
 public final class TestErrorReporter implements ErrorReporter {
   private final ArrayList<String> expectedErrors = new ArrayList<>();
   private final ArrayList<String> expectedWarnings = new ArrayList<>();
-  private final ArrayList<String> seenErrors = new ArrayList<>();
-  private final ArrayList<String> seenWarnings = new ArrayList<>();
+
+  // Seen diagnostics are stored in a LinkedHashMap to deduplicate identical diagnostics.
+  // The default com.google.javascript.jscomp.SortingErrorManager behaves in this way.
+  private final LinkedHashMap<String, String> seenErrors = new LinkedHashMap<>();
+  private final LinkedHashMap<String, String> seenWarnings = new LinkedHashMap<>();
 
   @Override
   public void error(String message, String sourceName, int line, int lineOffset) {
-    this.seenErrors.add(message);
+    seenErrors.put(fmtDiagnosticKey(message, sourceName, line, lineOffset), message);
   }
 
   @Override
   public void warning(String message, String sourceName, int line, int lineOffset) {
-    this.seenWarnings.add(message);
+    seenWarnings.put(fmtDiagnosticKey(message, sourceName, line, lineOffset), message);
   }
 
   public TestErrorReporter expectAllErrors(String... errors) {
@@ -75,7 +79,11 @@ public TestErrorReporter expectAllWarnings(String... warnings) {
   }
 
   public void verifyHasEncounteredAllWarningsAndErrors() {
-    assertThat(seenWarnings).containsExactlyElementsIn(expectedWarnings).inOrder();
-    assertThat(seenErrors).containsExactlyElementsIn(expectedErrors).inOrder();
+    assertThat(seenWarnings.values()).containsExactlyElementsIn(expectedWarnings).inOrder();
+    assertThat(seenErrors.values()).containsExactlyElementsIn(expectedErrors).inOrder();
+  }
+
+  private String fmtDiagnosticKey(String message, String sourceName, int line, int lineOffset) {
+    return message + ":" + sourceName + ":" + line + ":" + lineOffset;
   }
 }

test/com/google/javascript/jscomp/parsing/ParserTest.java

@@ -4121,6 +4121,21 @@ public void testStringContinuationIssue3492() {
     expectFeatures(Feature.STRING_CONTINUATION);
     strictMode = SLOPPY;
 
+    // This test runs on this input code, which technically has STRING_CONTINUATIONS_WARNINGs at 2
+    // places:
+    // ```
+    // function x() {
+    //    a = "\ <--- STRING_CONTINUATIONS_WARNING
+    //    \ \ <--- STRING_CONTINUATIONS_WARNING
+    //    ";
+    // };
+    // ```
+    // We deduplicate based on the key `sourceName:line_no:col_no:warning` being the same. Here,
+    // even though the `STRING_CONTINUATIONS_WARNING` happens at 2 places, JSCompiler reports the
+    // warnings within a string with a location pointing to the start of the string token. This
+    // happens here `charno(token.location.start)`:
+    // google3/third_party/java_src/jscomp/java/com/google/javascript/jscomp/parsing/IRFactory.java?rcl=719034735&l=3482
+    // Hence, after deduplication, we only get one error.
     parseWarning(
         lines(
             "function x() {", //
@@ -4129,7 +4144,6 @@ public void testStringContinuationIssue3492() {
             "        \";",
             "};"),
         "Unnecessary escape: '\\ ' is equivalent to just ' '",
-        STRING_CONTINUATIONS_WARNING,
         STRING_CONTINUATIONS_WARNING);
   }
 

test/com/google/javascript/rhino/jstype/JSTypeTest.java

@@ -4728,8 +4728,7 @@ public void testTypeOfThisIsProxied() {
   public void testNamedTypeEquals() {
     try (JSTypeResolver.Closer closer = registry.getResolver().openForDefinition()) {
       // test == if references are equal
-      errorReporter.expectAllWarnings(
-          "Bad type annotation. Unknown type type1", "Bad type annotation. Unknown type type1");
+      errorReporter.expectAllWarnings("Bad type annotation. Unknown type type1");
       NamedType a = registry.createNamedType(EMPTY_SCOPE, "type1", "source", 1, 0);
       NamedType b = registry.createNamedType(EMPTY_SCOPE, "type1", "source", 1, 0);
       assertThat(a.equals(b)).isTrue();

test/com/google/javascript/rhino/jstype/UnionTypeBuilderTest.java

@@ -157,7 +157,6 @@ public void testUnknownTypes() {
   @Test
   public void testUnresolvedNamedTypes() {
     errorReporter.expectAllWarnings(
-        "Bad type annotation. Unknown type not.resolved.A",
         "Bad type annotation. Unknown type not.resolved.A",
         "Bad type annotation. Unknown type not.resolved.B");