In UnicodeInCode, allow ASCII_SUB as the last character in the bu…

…ffer #3092 PiperOrigin-RevId: 467666418
google · Aug 15, 2022 · c3d267e · c3d267e
1 parent 3215a56
commit c3d267e
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Showing 2 changed files with 58 additions and 3 deletions.
diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/UnicodeInCode.java b/core/src/main/java/com/google/errorprone/bugpatterns/UnicodeInCode.java
@@ -51,9 +51,7 @@ public Description matchCompilationUnit(CompilationUnitTree tree, VisitorState s
     String sourceCode = state.getSourceCode().toString();
 
     for (int i = 0; i < sourceCode.length(); ++i) {
-      char c = sourceCode.charAt(i);
-
-      if (!isAcceptableAscii(c)) {
+      if (!isAcceptableAscii(sourceCode, i)) {
         violations.add(Range.closedOpen(i, i + 1));
       }
     }
@@ -83,6 +81,19 @@ public Description matchCompilationUnit(CompilationUnitTree tree, VisitorState s
     return NO_MATCH;
   }
 
+  private static boolean isAcceptableAscii(String sourceCode, int i) {
+    char c = sourceCode.charAt(i);
+    if (isAcceptableAscii(c)) {
+      return true;
+    }
+    if (c == 0x1a && i == sourceCode.length() - 1) {
+      // javac inserts ASCII_SUB characters at the end of the input, see:
+      // https://github.com/google/error-prone/issues/3092
+      return true;
+    }
+    return false;
+  }
+
   private static boolean isAcceptableAscii(char c) {
     return (c >= 0x20 && c <= 0x7E) || c == '\n' || c == '\r' || c == '\t';
   }

diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/UnicodeInCodeTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/UnicodeInCodeTest.java
@@ -16,7 +16,21 @@
 
 package com.google.errorprone.bugpatterns;
 
+import static com.google.common.truth.Truth.assertWithMessage;
+import static java.util.Locale.ENGLISH;
+import static java.util.stream.Collectors.joining;
+
+import com.google.common.collect.ImmutableList;
 import com.google.errorprone.CompilationTestHelper;
+import com.google.errorprone.FileManagers;
+import com.sun.source.util.JavacTask;
+import com.sun.tools.javac.api.JavacTool;
+import com.sun.tools.javac.file.JavacFileManager;
+import java.net.URI;
+import javax.tools.Diagnostic;
+import javax.tools.DiagnosticCollector;
+import javax.tools.JavaFileObject;
+import javax.tools.SimpleJavaFileObject;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
@@ -121,4 +135,34 @@ public void suppressibleAtMethodLevel() {
             "}")
         .doTest();
   }
+
+  @Test
+  public void asciiSub() {
+    JavacFileManager fileManager = FileManagers.testFileManager();
+    DiagnosticCollector<JavaFileObject> diagnosticCollector = new DiagnosticCollector<>();
+    JavacTask task =
+        JavacTool.create()
+            .getTask(
+                null,
+                fileManager,
+                diagnosticCollector,
+                ImmutableList.of("-Xplugin:ErrorProne", "-XDcompilePolicy=simple"),
+                ImmutableList.of(),
+                ImmutableList.of(
+                    new SimpleJavaFileObject(
+                        URI.create("file:///Test.java"), JavaFileObject.Kind.SOURCE) {
+                      @Override
+                      public String getCharContent(boolean ignoreEncodingErrors) {
+                        return "class Test {}" + ((char) 0x1a);
+                      }
+                    }));
+    boolean ok = task.call();
+    assertWithMessage(
+            diagnosticCollector.getDiagnostics().stream()
+                .filter(d -> d.getKind() == Diagnostic.Kind.ERROR)
+                .map(d -> d.getMessage(ENGLISH))
+                .collect(joining("\n")))
+        .that(ok)
+        .isTrue();
+  }
 }