Bug 560055 - Empty @throws-tag is not visibleI20210211-1810

- fix AbstractCommentParser.parseThrows() to reset properly
  after an invalid tag (e.g. missing throws name) to prevent
  an exception later and allowing the empty tag to be added
- add new tests to JavadocTestForMethod and ASTRewritingJavadocTest

Change-Id: I111099c144529e6609a246b72ad89bee67a961d8

3 files changed, 157 insertions, 3 deletions

diff --git a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/JavadocTestForMethod.java b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/JavadocTestForMethod.java
index e4d3006ec3..99c0af5c46 100644
--- a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/JavadocTestForMethod.java
+++ b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/JavadocTestForMethod.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2014 IBM Corporation and others.
+ * Copyright (c) 2000, 2021 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -4941,4 +4941,42 @@ public class JavadocTestForMethod extends JavadocTest {
 			"Javadoc: Invalid parameters declaration\n" +
 			"----------\n");
 	}
+
+	public void test164() {
+		this.runNegativeReferenceTest(
+			new String[] {
+				"X.java",
+				"package test;\n"
+					+ "public class X {\n"
+					+ "	/**\n"
+					+ "	 * Invalid param and throws tags\n"
+					+ "	 * \n"
+					+ "	 * @param\n"
+					+ "	 * @throws\n"
+					+ "	 */\n"
+					+ "	public void s_foo(int a) throws Exception {\n"
+					+ "	}\n"
+					+ "}\n" },
+					"----------\n"
+					+ "1. ERROR in X.java (at line 6)\n"
+					+ "	* @param\n"
+					+ "	   ^^^^^\n"
+					+ "Javadoc: Missing parameter name\n"
+					+ "----------\n"
+					+ "2. ERROR in X.java (at line 7)\n"
+					+ "	* @throws\n"
+					+ "	   ^^^^^^\n"
+					+ "Javadoc: Missing class name\n"
+					+ "----------\n"
+					+ "3. ERROR in X.java (at line 9)\n"
+					+ "	public void s_foo(int a) throws Exception {\n"
+					+ "	                      ^\n"
+					+ "Javadoc: Missing tag for parameter a\n"
+					+ "----------\n"
+					+ "4. ERROR in X.java (at line 9)\n"
+					+ "	public void s_foo(int a) throws Exception {\n"
+					+ "	                                ^^^^^^^^^\n"
+					+ "Javadoc: Missing tag for declared exception Exception\n"
+					+ "----------\n");
+	}
 }
diff --git a/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/rewrite/describing/ASTRewritingJavadocTest.java b/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/rewrite/describing/ASTRewritingJavadocTest.java
index 348e246ac1..5719c502da 100644
--- a/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/rewrite/describing/ASTRewritingJavadocTest.java
+++ b/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/rewrite/describing/ASTRewritingJavadocTest.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2015 IBM Corporation and others.
+ * Copyright (c) 2000, 2021 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -86,6 +86,116 @@ public class ASTRewritingJavadocTest extends ASTRewritingTest {
 		assertEqualString(preview, buf.toString());
 	}
 
+	public void testEmptyParamName() throws Exception {
+		// https://bugs.eclipse.org/bugs/show_bug.cgi?id=560055
+		IPackageFragment pack1= this.sourceFolder.createPackageFragment("test1", false, null);
+		StringBuffer buf= new StringBuffer();
+		buf.append("package test1;\n");
+		buf.append("public class E {\n");
+		buf.append("\n");
+		buf.append("    /**\n");
+		buf.append("     * @param\n");
+		buf.append("     */\n");
+		buf.append("    public void gee(String name) {\n");
+		buf.append("    }\n");
+		buf.append("}\n");
+		ICompilationUnit cu= pack1.createCompilationUnit("E.java", buf.toString(), false, null);
+
+		CompilationUnit astRoot= createAST(cu);
+		ASTRewrite rewrite= ASTRewrite.create(astRoot.getAST());
+		AST ast= astRoot.getAST();
+
+		{  // insert method at first position
+			TypeDeclaration type= findTypeDeclaration(astRoot, "E");
+			MethodDeclaration methodDecl= findMethodDeclaration(type, "gee");
+
+			Javadoc javadoc= methodDecl.getJavadoc();
+			List tags= javadoc.tags();
+			assertTrue("Has one tag", tags.size() == 1);
+
+			TagElement tagElement= (TagElement) tags.get(0);
+			List fragments= tagElement.fragments();
+			assertTrue("Has fragments", fragments.isEmpty());
+
+			TagElement newTagElement = ast.newTagElement();
+			newTagElement.setTagName(TagElement.TAG_PARAM);
+
+			SimpleName newName= ast.newSimpleName("newName");
+			newTagElement.fragments().add(newName);
+
+			rewrite.replace(tagElement, newTagElement, null);
+			}
+
+		String preview= evaluateRewrite(cu, rewrite);
+
+		buf= new StringBuffer();
+		buf.append("package test1;\n");
+		buf.append("public class E {\n");
+		buf.append("\n");
+		buf.append("    /**\n");
+		buf.append("     * @param newName\n");
+		buf.append("     */\n");
+		buf.append("    public void gee(String name) {\n");
+		buf.append("    }\n");
+		buf.append("}\n");
+		assertEqualString(preview, buf.toString());
+	}
+
+	public void testEmptyThrows() throws Exception {
+		// https://bugs.eclipse.org/bugs/show_bug.cgi?id=560055
+		IPackageFragment pack1= this.sourceFolder.createPackageFragment("test1", false, null);
+		StringBuffer buf= new StringBuffer();
+		buf.append("package test1;\n");
+		buf.append("public class E {\n");
+		buf.append("\n");
+		buf.append("    /**\n");
+		buf.append("     * @throws\n");
+		buf.append("     */\n");
+		buf.append("    public void gee(String name) {\n");
+		buf.append("    }\n");
+		buf.append("}\n");
+		ICompilationUnit cu= pack1.createCompilationUnit("E.java", buf.toString(), false, null);
+
+		CompilationUnit astRoot= createAST(cu);
+		ASTRewrite rewrite= ASTRewrite.create(astRoot.getAST());
+		AST ast= astRoot.getAST();
+
+		{  // insert method at first position
+			TypeDeclaration type= findTypeDeclaration(astRoot, "E");
+			MethodDeclaration methodDecl= findMethodDeclaration(type, "gee");
+
+			Javadoc javadoc= methodDecl.getJavadoc();
+			List tags= javadoc.tags();
+			assertTrue("Has one tag", tags.size() == 1);
+
+			TagElement tagElement= (TagElement) tags.get(0);
+			List fragments= tagElement.fragments();
+			assertTrue("Has fragments", fragments.isEmpty());
+
+			TagElement newTagElement = ast.newTagElement();
+			newTagElement.setTagName(TagElement.TAG_THROWS);
+
+			SimpleName newName= ast.newSimpleName("Exception");
+			newTagElement.fragments().add(newName);
+
+			rewrite.replace(tagElement, newTagElement, null);
+			}
+
+		String preview= evaluateRewrite(cu, rewrite);
+
+		buf= new StringBuffer();
+		buf.append("package test1;\n");
+		buf.append("public class E {\n");
+		buf.append("\n");
+		buf.append("    /**\n");
+		buf.append("     * @throws Exception\n");
+		buf.append("     */\n");
+		buf.append("    public void gee(String name) {\n");
+		buf.append("    }\n");
+		buf.append("}\n");
+		assertEqualString(preview, buf.toString());
+	}
+
 	public void testSeeTag1() throws Exception {
 		IPackageFragment pack1= this.sourceFolder.createPackageFragment("test1", false, null);
 		StringBuffer buf= new StringBuffer();
diff --git a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/parser/AbstractCommentParser.java b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/parser/AbstractCommentParser.java
index 937e392886..179236d111 100644
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/parser/AbstractCommentParser.java
+++ b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/parser/AbstractCommentParser.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2020 IBM Corporation and others.
+ * Copyright (c) 2000, 2021 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -1443,6 +1443,7 @@ public abstract class AbstractCommentParser implements JavadocTagConstants {
 	 */
 	protected boolean parseThrows() {
 		int start = this.scanner.currentPosition;
+		boolean isCompletionParser = (this.kind & COMPLETION_PARSER) != 0;
 		try {
 			Object typeRef = parseQualifiedName(true);
 			if (this.abort) return false; // May be aborted by specialized parser
@@ -1455,6 +1456,11 @@ public abstract class AbstractCommentParser implements JavadocTagConstants {
 		} catch (InvalidInputException ex) {
 			if (this.reportProblems) this.sourceParser.problemReporter().javadocInvalidThrowsClass(start, getTokenEndPosition());
 		}
+		if (!isCompletionParser) {
+			this.scanner.currentPosition = start;
+			this.index = start;
+		}
+		this.currentTokenType = -1;
 		return false;
 	}