Config: Match C git behavior more closely in escaping values

So this happened:

$ git config -f foo.config foo.a 'x"y'
$ git config -f foo.config foo.b x\\y
$ git config -f foo.config foo.c $'x\ny'
$ git config -f foo.config foo.d $'x\ty'
$ git config -f foo.config foo.e $'x\by'
$ cat foo.config
[foo]
        a = x\"y
        b = x\\y
        c = x\ny
        d = x\ty
        e = y

That last line is my shell interpreting the backspace byte:

$ python -c 'print repr(open("foo.config").read())'
'[foo]\n\ta = x\\"y\n\tb = x\\\\y\n\tc = x\\ny\n\td = x\\ty\n\te = x\x08y\n'

Change-Id: I1b059e1afb544c39ddb587c07bf79a06e99d0a09

2 files changed, 18 insertions, 7 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/T0003_BasicTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/T0003_BasicTest.java
index ab86bc2e27..aa50697172 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/T0003_BasicTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/T0003_BasicTest.java
@@ -368,7 +368,7 @@ public class T0003_BasicTest extends SampleDataRepositoryTestCase {
 				+ "[user]\n"
 				+ "  email = A U Thor <thor@example.com> # Just an example...\n"
 				+ " name = \"A  Thor \\\\ \\\"\\t \"\n"
-				+ "    defaultCheckInComment = \"a many line\\ncomment\\n to test\"\n";
+				+ "    defaultCheckInComment = a many line\\ncomment\\n to test\n";
 		assertEquals(expectedStr, new String(IO.readFully(cfg), Constants.CHARSET));
 	}
 
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ConfigTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ConfigTest.java
index 44714faa70..a952db764f 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ConfigTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ConfigTest.java
@@ -977,14 +977,25 @@ public class ConfigTest {
 	}
 
 	@Test
-	public void testEscapeSpecialCharacters() throws ConfigInvalidException {
+	public void testNoEscapeSpecialCharacters() throws ConfigInvalidException {
+		assertValueRoundTrip("x\\y", "x\\\\y");
+		assertValueRoundTrip("x\"y", "x\\\"y");
+		assertValueRoundTrip("x\ny", "x\\ny");
+		assertValueRoundTrip("x\ty", "x\\ty");
+		assertValueRoundTrip("x\by", "x\\by");
+	}
+
+	@Test
+	public void testParseLiteralBackspace() throws ConfigInvalidException {
+		// This is round-tripped with an escape sequence by JGit, but C git writes
+		// it out as a literal backslash.
+		assertEquals("x\by", parseEscapedValue("x\by"));
+	}
+
+	@Test
+	public void testEscapeCommentCharacters() throws ConfigInvalidException {
 		assertValueRoundTrip("x#y", "\"x#y\"");
 		assertValueRoundTrip("x;y", "\"x;y\"");
-		assertValueRoundTrip("x\\y", "\"x\\\\y\"");
-		assertValueRoundTrip("x\"y", "\"x\\\"y\"");
-		assertValueRoundTrip("x\ny", "\"x\\ny\"");
-		assertValueRoundTrip("x\ty", "\"x\\ty\"");
-		assertValueRoundTrip("x\by", "\"x\\by\"");
 	}
 
 	@Test