Re: [PATCH] Add a test-case for git-apply trying to add an ending line

From: Linus Torvalds <torvalds@osdl.org>
Date: May 24, 2006, 02:08 UTC
Message-ID: <Pine.LNX.4.64.0605231905470.5623@g5.osdl.org>
In-Reply-To: <7vhd3gxm73.fsf@assigned-by-dhcp.cox.net>

On Tue, 23 May 2006, Junio C Hamano wrote:

Show 10 quoted lines

> 
> Come to think of it, the above argument is bogus.  We _would_
> want to make EOF just like any other context lines.
> 
> The issue is if we can reliably tell if there is such an EOF
> context by looking at the diff.  Not having the same number of
> lines that starts with ' ' in the hunk is not really a nice way
> of doing so (you could make a unified diff that does not have
> trailing context at all), and I do not offhand think of a good
> way to do so.

We can. Something like this should do it.

(The same thing could be done for "match_beginning", perhaps).

Totally untested, of course.

(It might be better to pass in "match_end" to find_offset(), so that it could do the "look forwards" pass to see if it finds a better line offset that is at the end - as it is, this will _fail_ the patch if it could apply better at a non-end thing, even if it would _also_ have applied at the end of the file).

		Linus
---

diff --git a/apply.c b/apply.c
index 0ed9d13..905bf34 100644
--- a/apply.c
+++ b/apply.c
@@ -1333,6 +1333,7 @@ static int apply_line(char *output, cons
 
 static int apply_one_fragment(struct buffer_desc *desc, struct fragment *frag)
 {
+	int match_end;
 	char *buf = desc->buffer;
 	const char *patch = frag->patch;
 	int offset, size = frag->size;
@@ -1395,10 +1396,20 @@ #endif
 	newlines = new;
 	leading = frag->leading;
 	trailing = frag->trailing;
+
+	/*
+	 * If we don't have any trailing data in the patch,
+	 * we want to match the final ending '\0' byte in
+	 * the file too..
+	 */
+	match_end = !trailing;
+
 	lines = 0;
 	pos = frag->newpos;
 	for (;;) {
 		offset = find_offset(buf, desc->size, oldlines, oldsize, pos, &lines);
+		if (match_end && offset + oldsize != desc->size)
+			offset = -1;
 		if (offset >= 0) {
 			int diff = newsize - oldsize;
 			unsigned long size = desc->size + diff;
@@ -1428,6 +1439,10 @@ #endif
 		/* Am I at my context limits? */
 		if ((leading <= p_context) && (trailing <= p_context))
 			break;
+		if (match_end) {
+			match_end = 0;
+			continue;
+		}
 		/* Reduce the number of context lines
 		 * Reduce both leading and trailing if they are equal
 		 * otherwise just reduce the larger context.