Default for global (user) git ignore file

C git has a default for git config core.excludesfile: "Its default
value is $XDG_CONFIG_HOME/git/ignore. If $XDG_CONFIG_HOME is either
not set or empty, $HOME/.config/git/ignore is used instead." [1]

Implement this in the WorkingTreeIterator$RootIgnoreNode.

To make this testable, mock the "user.home" directory for all JGit
tests, otherwise tests might pick up a real user's git ignore file.
Also ensure that JGit code always reads "user.home" via the
SystemReader.

Add tests for both locations.

[1] https://git-scm.com/docs/gitignore#_description

Bug: 436127
Change-Id: Ie510259320286c3c13a6464a37da1bd9ca1e373a
Signed-off-by: Thomas Wolf <twolf@apache.org>

2 files changed, 115 insertions, 3 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/ignore/IgnoreNodeTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/ignore/IgnoreNodeTest.java
index 05a953e081..ab08c99796 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/ignore/IgnoreNodeTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/ignore/IgnoreNodeTest.java
@@ -20,14 +20,18 @@ import java.io.ByteArrayInputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Arrays;
 
+import org.eclipse.jgit.junit.MockSystemReader;
 import org.eclipse.jgit.junit.RepositoryTestCase;
 import org.eclipse.jgit.lib.FileMode;
 import org.eclipse.jgit.treewalk.FileTreeIterator;
 import org.eclipse.jgit.treewalk.TreeWalk;
 import org.eclipse.jgit.treewalk.WorkingTreeIterator;
+import org.eclipse.jgit.util.FS;
 import org.eclipse.jgit.util.FileUtils;
 import org.eclipse.jgit.util.SystemReader;
 import org.junit.After;
@@ -698,6 +702,110 @@ public class IgnoreNodeTest extends RepositoryTestCase {
 	}
 
 	@Test
+	public void testUserGitIgnoreFound() throws IOException {
+		File homeDir = FS.DETECTED.userHome();
+		Path userIgnore = homeDir.toPath().resolve(".config").resolve("git")
+				.resolve("ignore");
+		Files.createDirectories(userIgnore.getParent());
+		Files.writeString(userIgnore, "x");
+		try {
+			writeTrashFile(".foo", "");
+			writeTrashFile("a/x/file", "");
+			writeTrashFile("b/x", "");
+			writeTrashFile("x/file", "");
+
+			beginWalk();
+			assertEntry(F, tracked, ".foo");
+			assertEntry(D, tracked, "a");
+			assertEntry(D, ignored, "a/x");
+			assertEntry(F, ignored, "a/x/file");
+			assertEntry(D, tracked, "b");
+			assertEntry(F, ignored, "b/x");
+			assertEntry(D, ignored, "x");
+			assertEntry(F, ignored, "x/file");
+			endWalk();
+		} finally {
+			Files.deleteIfExists(userIgnore);
+		}
+	}
+
+	@Test
+	public void testXdgIgnoreFound() throws IOException {
+		File tmp = getTemporaryDirectory();
+		Path xdg = tmp.toPath().resolve("xdg");
+		Path userIgnore = xdg.resolve("git").resolve("ignore");
+		Files.createDirectories(userIgnore.getParent());
+		Files.writeString(userIgnore, "x");
+		SystemReader system = SystemReader.getInstance();
+		assertTrue(system instanceof MockSystemReader);
+		((MockSystemReader) system).setProperty("XDG_CONFIG_HOME",
+				xdg.toAbsolutePath().toString());
+		// Also create the one in the home directory -- it should not be active
+		File homeDir = FS.DETECTED.userHome();
+		Path userIgnore2 = homeDir.toPath().resolve(".config").resolve("git")
+				.resolve("ignore");
+		Files.createDirectories(userIgnore2.getParent());
+		Files.writeString(userIgnore2, "a");
+		try {
+			writeTrashFile(".foo", "");
+			writeTrashFile("a/x/file", "");
+			writeTrashFile("b/x", "");
+			writeTrashFile("x/file", "");
+
+			beginWalk();
+			assertEntry(F, tracked, ".foo");
+			assertEntry(D, tracked, "a");
+			assertEntry(D, ignored, "a/x");
+			assertEntry(F, ignored, "a/x/file");
+			assertEntry(D, tracked, "b");
+			assertEntry(F, ignored, "b/x");
+			assertEntry(D, ignored, "x");
+			assertEntry(F, ignored, "x/file");
+			endWalk();
+		} finally {
+			((MockSystemReader) system).setProperty("XDG_CONFIG_HOME", null);
+			Files.deleteIfExists(userIgnore2);
+		}
+	}
+
+	@Test
+	public void testXdgWrong() throws IOException {
+		File tmp = getTemporaryDirectory();
+		Path xdg = tmp.toPath().resolve("xdg");
+		SystemReader system = SystemReader.getInstance();
+		assertTrue(system instanceof MockSystemReader);
+		// Valid value, but the directory doesn't exist
+		((MockSystemReader) system).setProperty("XDG_CONFIG_HOME",
+				xdg.toAbsolutePath().toString());
+		// Also create the one in the home directory -- it should not be active
+		File homeDir = FS.DETECTED.userHome();
+		Path userIgnore2 = homeDir.toPath().resolve(".config").resolve("git")
+				.resolve("ignore");
+		Files.createDirectories(userIgnore2.getParent());
+		Files.writeString(userIgnore2, "x");
+		try {
+			writeTrashFile(".foo", "");
+			writeTrashFile("a/x/file", "");
+			writeTrashFile("b/x", "");
+			writeTrashFile("x/file", "");
+
+			beginWalk();
+			assertEntry(F, tracked, ".foo");
+			assertEntry(D, tracked, "a");
+			assertEntry(D, tracked, "a/x");
+			assertEntry(F, tracked, "a/x/file");
+			assertEntry(D, tracked, "b");
+			assertEntry(F, tracked, "b/x");
+			assertEntry(D, tracked, "x");
+			assertEntry(F, tracked, "x/file");
+			endWalk();
+		} finally {
+			((MockSystemReader) system).setProperty("XDG_CONFIG_HOME", null);
+			Files.deleteIfExists(userIgnore2);
+		}
+	}
+
+	@Test
 	public void testToString() throws Exception {
 		assertEquals(Arrays.asList("").toString(), new IgnoreNode().toString());
 		assertEquals(Arrays.asList("hello").toString(),
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/CommitTemplateConfigTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/CommitTemplateConfigTest.java
index 42bafb60ca..3ccd0ef021 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/CommitTemplateConfigTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/CommitTemplateConfigTest.java
@@ -17,7 +17,9 @@ import java.io.IOException;
 
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.junit.JGitTestUtil;
+import org.eclipse.jgit.junit.LocalDiskRepositoryTestCase;
 import org.eclipse.jgit.storage.file.FileRepositoryBuilder;
+import org.eclipse.jgit.util.FS;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
@@ -27,7 +29,7 @@ import org.junit.rules.TemporaryFolder;
  * test using bazel which doesn't allow tests to create files in the home
  * directory
  */
-public class CommitTemplateConfigTest {
+public class CommitTemplateConfigTest extends LocalDiskRepositoryTestCase {
 
 	@Rule
 	public TemporaryFolder tmp = new TemporaryFolder();
@@ -42,9 +44,11 @@ public class CommitTemplateConfigTest {
 		String templateContent = "content of the template";
 		JGitTestUtil.write(tempFile, templateContent);
 		// proper evaluation of the ~/ directory
-		String homeDir = System.getProperty("user.home");
+		File homeDir = FS.DETECTED.userHome();
 		File tempFileInHomeDirectory = File.createTempFile("fileInHomeFolder",
-				".tmp", new File(homeDir));
+				".tmp", homeDir);
+		// The home directory should be a mocked temporary directory, but
+		// still...
 		tempFileInHomeDirectory.deleteOnExit();
 		JGitTestUtil.write(tempFileInHomeDirectory, templateContent);
 		String expectedTemplatePath = "~/" + tempFileInHomeDirectory.getName();