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Fix hunk apply failure caused by trailing whitespace mismatch (#10)
* Fix hunk apply failure caused by trailing whitespace mismatch * Improve test coverage: migrate to AssertJ and add negative test Switch ApplyCommandTest from JUnit assertTrue to AssertJ assertions for better failure messages. Add negative test to verify genuinely mismatched context lines are still rejected. Extract multiHunkPatch helper method.
1 parent a70606c commit 37244d5

4 files changed

Lines changed: 254 additions & 1 deletion

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‎jgit/build.gradle.kts‎

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@@ -5,6 +5,10 @@ plugins {
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dependencies {
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implementation("com.googlecode.javaewah:JavaEWAH:1.1.13")
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compileOnly("org.slf4j:slf4j-api:1.7.36")
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testImplementation("org.assertj:assertj-core:3.26.3") {
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version { strictly("3.26.3") }
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}
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testRuntimeOnly("org.slf4j:slf4j-simple:1.7.36")
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}
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java {

‎jgit/src/main/java/org/openrewrite/jgit/api/ApplyCommand.java‎

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@@ -760,7 +760,8 @@ private boolean canApplyAt(List<ByteBuffer> hunkLines,
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case ' ':
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case '-':
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if (pos >= limit
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|| !newLines.get(pos).equals(slice(hunkLine, 1))) {
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|| !equalsIgnoringTrailingWhitespace(
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newLines.get(pos), slice(hunkLine, 1))) {
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return false;
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}
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pos++;
@@ -777,6 +778,35 @@ private ByteBuffer slice(ByteBuffer b, int off) {
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return ByteBuffer.wrap(b.array(), newOffset, b.limit() - newOffset);
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}
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private static boolean equalsIgnoringTrailingWhitespace(ByteBuffer a,
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ByteBuffer b) {
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int aEnd = a.limit();
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while (aEnd > a.position()
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&& isWhitespace(a.array()[aEnd - 1])) {
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aEnd--;
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}
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int bEnd = b.limit();
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while (bEnd > b.position()
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&& isWhitespace(b.array()[bEnd - 1])) {
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bEnd--;
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}
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int aLen = aEnd - a.position();
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int bLen = bEnd - b.position();
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if (aLen != bLen) {
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return false;
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}
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for (int i = 0; i < aLen; i++) {
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if (a.array()[a.position() + i] != b.array()[b.position() + i]) {
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return false;
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}
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}
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return true;
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}
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private static boolean isWhitespace(byte b) {
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return b == ' ' || b == '\t' || b == '\r';
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}
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private boolean isNoNewlineAtEndOfFile(FileHeader fh) {
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List<? extends HunkHeader> hunks = fh.getHunks();
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if (hunks == null || hunks.isEmpty()) {

‎jgit/src/main/java/org/openrewrite/jgit/patch/FileHeader.java‎

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@@ -556,6 +556,9 @@ private String parseName(String expect, int ptr, int end) {
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r = decode(UTF_8, buf, ptr, tab - 1);
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}
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if (r.endsWith("\r")) {
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r = r.substring(0, r.length() - 1);
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}
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if (r.equals(DEV_NULL))
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r = DEV_NULL;
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return r;

‎jgit/src/test/java/org/openrewrite/jgit/api/ApplyCommandTest.java‎

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@@ -0,0 +1,216 @@
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/*
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* Copyright (C) 2026, OpenRewrite and others
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*
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* This program and the accompanying materials are made available under the
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* terms of the Eclipse Distribution License v. 1.0 which is available at
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* https://www.eclipse.org/org/documents/edl-v10.php.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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package org.openrewrite.jgit.api;
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import org.junit.jupiter.api.AfterEach;
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import org.junit.jupiter.api.BeforeEach;
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import org.junit.jupiter.api.Test;
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import org.openrewrite.jgit.api.errors.PatchApplyException;
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import org.openrewrite.jgit.lib.Repository;
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import org.openrewrite.jgit.util.FileUtils;
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import java.io.ByteArrayInputStream;
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import java.io.File;
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import java.io.FileOutputStream;
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import java.io.IOException;
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import java.io.InputStream;
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import java.nio.charset.StandardCharsets;
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import java.nio.file.Files;
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import static org.assertj.core.api.Assertions.assertThat;
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import static org.assertj.core.api.Assertions.assertThatThrownBy;
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/**
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* Tests for {@link ApplyCommand}, focusing on multi-hunk patch application.
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*/
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public class ApplyCommandTest {
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private Repository db;
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private Git git;
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private File trash;
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@BeforeEach
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public void setUp() throws Exception {
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trash = Files.createTempDirectory("jgit-apply-test").toFile();
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git = Git.init().setDirectory(trash).call();
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db = git.getRepository();
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}
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@AfterEach
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public void tearDown() throws Exception {
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if (db != null) {
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db.close();
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}
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if (trash != null) {
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FileUtils.delete(trash, FileUtils.RECURSIVE | FileUtils.RETRY);
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}
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}
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/**
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* Test applying a multi-hunk patch where both the file and patch use LF line endings.
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*/
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@Test
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public void testMultiHunkPatchWithLF() throws Exception {
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StringBuilder fileContent = new StringBuilder();
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for (int i = 1; i <= 150; i++) {
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fileContent.append("Line ").append(i).append('\n');
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}
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writeFileAndCommit("test.txt", fileContent.toString());
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String patch = multiHunkPatch("\n");
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ApplyResult result = applyPatch(patch);
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assertThat(result.getUpdatedFiles()).isNotEmpty();
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String resultContent = readFile("test.txt");
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assertThat(resultContent).contains("New Line A1", "New Line A6",
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"New Line B");
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}
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/**
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* Test applying a patch with CRLF line endings to a file with LF line
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* endings.
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*/
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@Test
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public void testMultiHunkPatchWithCRLFPatchAndLFFile() throws Exception {
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StringBuilder fileContent = new StringBuilder();
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for (int i = 1; i <= 150; i++) {
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fileContent.append("Line ").append(i).append('\n');
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}
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writeFileAndCommit("test.txt", fileContent.toString());
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String patch = multiHunkPatch("\r\n");
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ApplyResult result = applyPatch(patch);
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assertThat(result.getUpdatedFiles()).isNotEmpty();
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String resultContent = readFile("test.txt");
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assertThat(resultContent).contains("New Line A1", "New Line B");
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}
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/**
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* Test applying a patch with LF line endings to a file with CRLF line
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* endings.
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*/
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@Test
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public void testMultiHunkPatchWithLFPatchAndCRLFFile() throws Exception {
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StringBuilder fileContent = new StringBuilder();
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for (int i = 1; i <= 150; i++) {
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fileContent.append("Line ").append(i).append("\r\n");
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}
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writeFileAndCommit("test.txt", fileContent.toString());
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String patch = multiHunkPatch("\n");
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ApplyResult result = applyPatch(patch);
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assertThat(result.getUpdatedFiles()).isNotEmpty();
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String resultContent = readFile("test.txt");
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assertThat(resultContent).contains("New Line A1", "New Line B");
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}
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/**
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* Test applying a patch where the file has trailing whitespace on some
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* context lines but the patch does not.
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*/
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@Test
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public void testMultiHunkPatchWithTrailingWhitespaceDifference()
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throws Exception {
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StringBuilder fileContent = new StringBuilder();
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for (int i = 1; i <= 150; i++) {
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if (i == 118 || i == 119 || i == 120) {
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fileContent.append("Line ").append(i).append(" \n");
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} else {
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fileContent.append("Line ").append(i).append('\n');
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}
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}
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writeFileAndCommit("test.txt", fileContent.toString());
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String patch = multiHunkPatch("\n");
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ApplyResult result = applyPatch(patch);
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assertThat(result.getUpdatedFiles()).isNotEmpty();
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String resultContent = readFile("test.txt");
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assertThat(resultContent).contains("New Line A1", "New Line B");
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}
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/**
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* Test that a patch with genuinely mismatched context lines is still
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* rejected.
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*/
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@Test
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public void testMultiHunkPatchWithMismatchedContextIsRejected()
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throws Exception {
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StringBuilder fileContent = new StringBuilder();
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for (int i = 1; i <= 150; i++) {
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fileContent.append("Line ").append(i).append('\n');
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}
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// Replace line 119 with completely different content
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String content = fileContent.toString()
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.replace("Line 119\n", "DIFFERENT CONTENT\n");
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writeFileAndCommit("test.txt", content);
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String patch = multiHunkPatch("\n");
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assertThatThrownBy(() -> applyPatch(patch))
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.isInstanceOf(PatchApplyException.class)
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.hasMessageContaining("hunk");
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}
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private String multiHunkPatch(String eol) {
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return "diff --git a/test.txt b/test.txt" + eol
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+ "--- a/test.txt" + eol
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+ "+++ b/test.txt" + eol
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+ "@@ -10,6 +10,12 @@" + eol
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+ " Line 10" + eol
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+ " Line 11" + eol
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+ " Line 12" + eol
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+ "+New Line A1" + eol
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+ "+New Line A2" + eol
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+ "+New Line A3" + eol
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+ "+New Line A4" + eol
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+ "+New Line A5" + eol
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+ "+New Line A6" + eol
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+ " Line 13" + eol
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+ " Line 14" + eol
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+ " Line 15" + eol
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+ "@@ -118,6 +124,7 @@" + eol
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+ " Line 118" + eol
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+ " Line 119" + eol
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+ " Line 120" + eol
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+ "+New Line B" + eol
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+ " Line 121" + eol
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+ " Line 122" + eol
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+ " Line 123" + eol;
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}
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private void writeFileAndCommit(String name, String content)
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throws Exception {
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File f = new File(trash, name);
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try (FileOutputStream fos = new FileOutputStream(f)) {
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fos.write(content.getBytes(StandardCharsets.UTF_8));
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}
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git.add().addFilepattern(name).call();
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git.commit().setMessage("initial").call();
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}
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private ApplyResult applyPatch(String patch) throws Exception {
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InputStream in = new ByteArrayInputStream(
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patch.getBytes(StandardCharsets.UTF_8));
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return git.apply().setPatch(in).call();
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}
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private String readFile(String name) throws IOException {
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File f = new File(trash, name);
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return new String(Files.readAllBytes(f.toPath()),
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StandardCharsets.UTF_8);
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}
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}

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