Re: [PATCH] Teach 'git-apply --whitespace=strip' to remove empty lines at the end of file

From

MCMarco Costalba <mcostalba@gmail.com>

Date

May 20, 2007, 12:45 UTC

Message-ID

<e5bfff550705200545kcf1f7f9n4f3f6d7d25955e1@mail.gmail.com>

In-Reply-To

<7vabvzoij8.fsf@assigned-by-dhcp.cox.net>

On 5/20/07, Junio C Hamano <junkio@cox.net> wrote:

>
> I was starting to suspect that I misunderstood what you were
> trying to do.  I thought you were trying to avoid a patch that
> adds (one or more) blank line(s) at the end of the file, but is
> it that you do not want to have a hunk that adds more than one
> blank line anywhere?  However, the comment "Only fragments that
> add lines at the bottom ends with '+' lines" suggests otherwise.
>

No, you understand right.

>
> Because we had the same mistake in our earlier code as you made
> in this patch, which assumed that a hunk that ends with '+' only
> apply at the end (and we still assume that by default), if you
> apply this with patch git-apply without --unidiff-zero option,
> you get an error.  If you use the option this patch can be
> applied correctly.
>

This patch is on top of git 1.5.2

Please check it.

builtin-apply.c |   34 ++++++++++++++++++++++++++++++++++
 1 files changed, 34 insertions(+), 0 deletions(-)

diff --git a/builtin-apply.c b/builtin-apply.c
index 0399743..6032f78 100644
--- a/builtin-apply.c
+++ b/builtin-apply.c
@@ -1671,6 +1671,7 @@ static int apply_one_fragment(struct buffer_desc *desc,
 	char *new = xmalloc(size);
 	const char *oldlines, *newlines;
 	int oldsize = 0, newsize = 0;
+	int trailing_added_lines = 0;
 	unsigned long leading, trailing;
 	int pos, lines;

@@ -1699,6 +1700,17 @@ static int apply_one_fragment(struct buffer_desc *desc,
 			else if (first == '+')
 				first = '-';
 		}
+		/*
+		 * Count lines added at the end of the file.
+		 * This is not enough to get things right in case of
+		 * patches generated with --unified=0, but it's a
+		 * useful upper bound.
+		*/
+		if (first == '+')
+			trailing_added_lines++;
+		else
+			trailing_added_lines = 0;
+
 		switch (first) {
 		case '\n':
 			/* Newer GNU diff, empty context line */
@@ -1738,6 +1750,24 @@ static int apply_one_fragment(struct buffer_desc *desc,
 		newsize--;
 	}

+	if (new_whitespace == strip_whitespace) {
+		/* Any added empty lines is already cleaned-up here
+		 * becuase of 'strip_whitespace' flag, so just count '\n'
+		*/
+		int empty = 0;
+		while (   empty < trailing_added_lines
+		       && newsize - empty > 0
+		       && new[newsize - empty - 1] == '\n')
+			empty++;
+
+		if (empty < trailing_added_lines)
+			empty--;
+
+		/* these are the empty lines added at
+		 * the end of the file, modulo u0 patches.
+		 */
+		trailing_added_lines = empty;
+	}
 	oldlines = old;
 	newlines = new;
 	leading = frag->leading;
@@ -1770,6 +1800,10 @@ static int apply_one_fragment(struct buffer_desc *desc,
 		if (match_beginning && offset)
 			offset = -1;
 		if (offset >= 0) {
+
+			if (desc->size - oldsize - offset == 0) /* end of file? */
+				newsize -= trailing_added_lines;
+
 			int diff = newsize - oldsize;
 			unsigned long size = desc->size + diff;
 			unsigned long alloc = desc->alloc;