LFS: handle invalid pointers better

Make sure that SmudgeFilter calls LfsPointer.parseLfsPointer() with
a stream that supports mark/reset, and make sure that parseLfsPointer()
resets the stream properly if it decides that the stream content is not
a LFS pointer.

Add a test.

Bug: 570758
Change-Id: I2593d67cff31b2dfdfaaa48e437331f0ed877915
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

1 files changed, 141 insertions, 0 deletions

diff --git a/org.eclipse.jgit.lfs.test/tst/org/eclipse/jgit/lfs/LfsGitTest.java b/org.eclipse.jgit.lfs.test/tst/org/eclipse/jgit/lfs/LfsGitTest.java
new file mode 100644
index 0000000000..8964310e41
--- /dev/null
+++ b/org.eclipse.jgit.lfs.test/tst/org/eclipse/jgit/lfs/LfsGitTest.java
@@ -0,0 +1,141 @@
+/*
+ * Copyright (C) 2021, Thomas Wolf <thomas.wolf@paranor.ch> and others
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Distribution License v. 1.0 which is available at
+ * https://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+package org.eclipse.jgit.lfs;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.io.File;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+
+import org.eclipse.jgit.api.Git;
+import org.eclipse.jgit.api.ResetCommand.ResetType;
+import org.eclipse.jgit.attributes.FilterCommandRegistry;
+import org.eclipse.jgit.junit.RepositoryTestCase;
+import org.eclipse.jgit.lfs.lib.Constants;
+import org.eclipse.jgit.lib.StoredConfig;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class LfsGitTest extends RepositoryTestCase {
+
+	private static final String SMUDGE_NAME = org.eclipse.jgit.lib.Constants.BUILTIN_FILTER_PREFIX
+			+ Constants.ATTR_FILTER_DRIVER_PREFIX
+			+ org.eclipse.jgit.lib.Constants.ATTR_FILTER_TYPE_SMUDGE;
+
+	private static final String CLEAN_NAME = org.eclipse.jgit.lib.Constants.BUILTIN_FILTER_PREFIX
+			+ Constants.ATTR_FILTER_DRIVER_PREFIX
+			+ org.eclipse.jgit.lib.Constants.ATTR_FILTER_TYPE_CLEAN;
+
+	@BeforeClass
+	public static void installLfs() {
+		FilterCommandRegistry.register(SMUDGE_NAME, SmudgeFilter.FACTORY);
+		FilterCommandRegistry.register(CLEAN_NAME, CleanFilter.FACTORY);
+	}
+
+	@AfterClass
+	public static void removeLfs() {
+		FilterCommandRegistry.unregister(SMUDGE_NAME);
+		FilterCommandRegistry.unregister(CLEAN_NAME);
+	}
+
+	private Git git;
+
+	@Override
+	@Before
+	public void setUp() throws Exception {
+		super.setUp();
+		git = new Git(db);
+		// commit something
+		writeTrashFile("Test.txt", "Hello world");
+		git.add().addFilepattern("Test.txt").call();
+		git.commit().setMessage("Initial commit").call();
+		// prepare the config for LFS
+		StoredConfig config = git.getRepository().getConfig();
+		config.setString("filter", "lfs", "clean", CLEAN_NAME);
+		config.setString("filter", "lfs", "smudge", SMUDGE_NAME);
+		config.save();
+	}
+
+	@Test
+	public void checkoutNonLfsPointer() throws Exception {
+		String content = "size_t\nsome_function(void* ptr);\n";
+		File smallFile = writeTrashFile("Test.txt", content);
+		StringBuilder largeContent = new StringBuilder(
+				LfsPointer.SIZE_THRESHOLD * 4);
+		while (largeContent.length() < LfsPointer.SIZE_THRESHOLD * 4) {
+			largeContent.append(content);
+		}
+		File largeFile = writeTrashFile("large.txt", largeContent.toString());
+		fsTick(largeFile);
+		git.add().addFilepattern("Test.txt").addFilepattern("large.txt").call();
+		git.commit().setMessage("Text files").call();
+		writeTrashFile(".gitattributes", "*.txt filter=lfs");
+		git.add().addFilepattern(".gitattributes").call();
+		git.commit().setMessage("attributes").call();
+		assertTrue(smallFile.delete());
+		assertTrue(largeFile.delete());
+		// This reset will run the two text files through the smudge filter
+		git.reset().setMode(ResetType.HARD).call();
+		assertTrue(smallFile.exists());
+		assertTrue(largeFile.exists());
+		checkFile(smallFile, content);
+		checkFile(largeFile, largeContent.toString());
+		// Modify the large file
+		largeContent.append(content);
+		writeTrashFile("large.txt", largeContent.toString());
+		// This should convert largeFile to an LFS pointer
+		git.add().addFilepattern("large.txt").call();
+		git.commit().setMessage("Large modified").call();
+		String lfsPtr = "version https://git-lfs.github.com/spec/v1\n"
+				+ "oid sha256:d041ab19bd7edd899b3c0450d0f61819f96672f0b22d26c9753abc62e1261614\n"
+				+ "size 858\n";
+		assertEquals("[.gitattributes, mode:100644, content:*.txt filter=lfs]"
+				+ "[Test.txt, mode:100644, content:" + content + ']'
+						+ "[large.txt, mode:100644, content:" + lfsPtr + ']',
+				indexState(CONTENT));
+		// Verify the file has been saved
+		File savedFile = new File(db.getDirectory(), "lfs");
+		savedFile = new File(savedFile, "objects");
+		savedFile = new File(savedFile, "d0");
+		savedFile = new File(savedFile, "41");
+		savedFile = new File(savedFile,
+				"d041ab19bd7edd899b3c0450d0f61819f96672f0b22d26c9753abc62e1261614");
+		String saved = new String(Files.readAllBytes(savedFile.toPath()),
+				StandardCharsets.UTF_8);
+		assertEquals(saved, largeContent.toString());
+
+		assertTrue(smallFile.delete());
+		assertTrue(largeFile.delete());
+		git.reset().setMode(ResetType.HARD).call();
+		assertTrue(smallFile.exists());
+		assertTrue(largeFile.exists());
+		checkFile(smallFile, content);
+		checkFile(largeFile, largeContent.toString());
+		assertEquals("[.gitattributes, mode:100644, content:*.txt filter=lfs]"
+				+ "[Test.txt, mode:100644, content:" + content + ']'
+						+ "[large.txt, mode:100644, content:" + lfsPtr + ']',
+				indexState(CONTENT));
+		git.add().addFilepattern("Test.txt").call();
+		git.commit().setMessage("Small committed again").call();
+		String lfsPtrSmall = "version https://git-lfs.github.com/spec/v1\n"
+				+ "oid sha256:9110463275fb0e2f0e9fdeaf84e598e62915666161145cf08927079119cc7814\n"
+				+ "size 33\n";
+		assertEquals("[.gitattributes, mode:100644, content:*.txt filter=lfs]"
+				+ "[Test.txt, mode:100644, content:" + lfsPtrSmall + ']'
+						+ "[large.txt, mode:100644, content:" + lfsPtr + ']',
+				indexState(CONTENT));
+
+		assertTrue(git.status().call().isClean());
+	}
+}