[JGIT PATCH 2/2] improve the handling of empty lines

Mark Struberg· Sep 2, 2009, 18:00 UTC · lore

[JGIT PATCH 1/2] fixed error in whitespace handling of RefDatabase#readLine

jgit fails with "cannot checkout; no HEAD advertised by remote" in guessHEAD on some repositories.

JGIT used to work on my test repo for the maven-scm-providers-git until a few weeks. I tracked it down with git bisect and found commit 72b1f0d334729a49cc52e4762093148be62bea39 to be the bad one.

I glimpsed at the code and it appears that the new code in RefDatabase#readLine is not Windows CR+LF aware. (This hits me although I use Linux because our SVN at apache.org seems to have it stored with CR+LF.)

Fixed by subsequently removing all Character.isWhitespaceChar() from the end of the buffer

Signed-off-by: Mark Struberg <struberg@yahoo.de>
---
 .../src/org/spearce/jgit/lib/RefDatabase.java      |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

Show changes to org.spearce.jgit/src/org/spearce/jgit/lib/RefDatabase.java +5 −1

diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/RefDatabase.java b/org.spearce.jgit/src/org/spearce/jgit/lib/RefDatabase.java
index ba4b654..477dc62 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/lib/RefDatabase.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/lib/RefDatabase.java
@@ -500,8 +500,12 @@ private static String readLine(final File file)
 		int n = buf.length;
 		if (n == 0)
 			return null;
-		if (buf[n - 1] == '\n')
+		
+		// remove trailing whitespaces
+		while (n > 0 && Character.isWhitespace(buf[n - 1])) {
 			n--;
+		}
+		
 		return RawParseUtils.decode(buf, 0, n);
 	}

-- 
1.6.2.5

Mark Struberg· Sep 2, 2009, 18:00 UTC · re: Mark Struberg · lore

Move the 'empty-line' check in RefDatabase#readLine down a bit after we removed all the whitespaces. This way we consistently return null regardless if the line is empty or if it does only contain whitespaces.

Signed-off-by: Mark Struberg <struberg@yahoo.de>
---
 .../src/org/spearce/jgit/lib/RefDatabase.java      |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

Show changes to org.spearce.jgit/src/org/spearce/jgit/lib/RefDatabase.java +4 −3

diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/RefDatabase.java b/org.spearce.jgit/src/org/spearce/jgit/lib/RefDatabase.java
index 477dc62..acc835b 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/lib/RefDatabase.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/lib/RefDatabase.java
@@ -498,14 +498,15 @@ private static String readLine(final File file)
 			throws FileNotFoundException, IOException {
 		final byte[] buf = NB.readFully(file, 4096);
 		int n = buf.length;
-		if (n == 0)
-			return null;
 		
 		// remove trailing whitespaces
 		while (n > 0 && Character.isWhitespace(buf[n - 1])) {
 			n--;
 		}
-		
+
+		if (n == 0)
+			return null;
+
 		return RawParseUtils.decode(buf, 0, n);
 	}

-- 
1.6.2.5

patch, 2 partsimprove the handling of empty lines