Config: Drop backslash in invalid escape sequences in subsections

These are ignored by C git when parsing:

$ git config -f - --list <<EOF
[foo "x\0y"]
bar = baz
[foo "x\qy"]
bar = baz
[foo "x\by"]
bar = baz
[foo "x\ny"]
bar = baz
[foo "x\ty"]
bar = baz
EOF
foo.x0y.bar=baz
foo.xqy.bar=baz
foo.xby.bar=baz
foo.xny.bar=baz
foo.xty.bar=baz

This behavior is different from value parsing, where an invalid escape
sequence is an error (which JGit already does as well):

$ git config -f - --list <<EOF
[foo]
bar = x\qy
EOF
fatal: bad config line 2 in standard input

Change-Id: Ifd40129b37d9a62df3d886d8d7e22f766f54e9d1

1 files changed, 9 insertions, 8 deletions

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 a952db764f..2609f6745e 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
@@ -1056,16 +1056,17 @@ public class ConfigTest {
 	public void testParseInvalidSubsections() {
 		assertInvalidSubsection(
 				JGitText.get().newlineInQuotesNotAllowed, "\"x\ny\"");
-		assertInvalidSubsection(
-				MessageFormat.format(JGitText.get().badEscape, 'q'), "\"x\\q\"");
+	}
 
+	@Test
+	public void testDropBackslashFromInvalidEscapeSequenceInSubsectionName()
+			throws ConfigInvalidException {
+		assertEquals("x0", parseEscapedSubsection("\"x\\0\""));
+		assertEquals("xq", parseEscapedSubsection("\"x\\q\""));
 		// Unlike for values, \b, \n, and \t are not valid escape sequences.
-		assertInvalidSubsection(
-				MessageFormat.format(JGitText.get().badEscape, 'b'), "\"x\\b\"");
-		assertInvalidSubsection(
-				MessageFormat.format(JGitText.get().badEscape, 'n'), "\"x\\n\"");
-		assertInvalidSubsection(
-				MessageFormat.format(JGitText.get().badEscape, 't'), "\"x\\t\"");
+		assertEquals("xb", parseEscapedSubsection("\"x\\b\""));
+		assertEquals("xn", parseEscapedSubsection("\"x\\n\""));
+		assertEquals("xt", parseEscapedSubsection("\"x\\t\""));
 	}
 
 	private static void assertValueRoundTrip(String value)