[PATCH 08/19] built-in add -p: handle deleted empty files

From: Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>
Date: Dec 13, 2019, 08:07 UTC
Message-ID: <556604361d28377e4f453b851527293ae865c27a.1576224486.git.gitgitgadget@gmail.com>
In-Reply-To: <pull.173.git.1576224486.gitgitgadget@gmail.com>

From: Johannes Schindelin <johannes.schindelin@gmx.de>

This addresses the same problem as 24ab81ae4d (add-interactive: handle deletion of empty files, 2009-10-27), although in a different way: we not only stick the "deleted file" line into its own pseudo hunk, but also the entire remainder (if any) of the same diff.

That way, we do not have to play any funny games with regards to coalescing the diff after the user selected what (possibly pseudo-)hunks to stage.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-patch.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/add-patch.c b/add-patch.c
index 7c1b3b3935..c32541f46d 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -33,6 +33,7 @@ struct add_p_state {
 		struct hunk head;
 		struct hunk *hunk;
 		size_t hunk_nr, hunk_alloc;
+		unsigned deleted:1;
 	} *file_diff;
 	size_t file_diff_nr;
 };
@@ -180,6 +181,8 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 	pend = p + plain->len;
 	while (p != pend) {
 		char *eol = memchr(p, '\n', pend - p);
+		const char *deleted = NULL;
+
 		if (!eol)
 			eol = pend;
 
@@ -196,7 +199,11 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 		} else if (p == plain->buf)
 			BUG("diff starts with unexpected line:\n"
 			    "%.*s\n", (int)(eol - p), p);
-		else if (starts_with(p, "@@ ")) {
+		else if (file_diff->deleted)
+			; /* keep the rest of the file in a single "hunk" */
+		else if (starts_with(p, "@@ ") ||
+			 (hunk == &file_diff->head &&
+			  skip_prefix(p, "deleted file", &deleted))) {
 			file_diff->hunk_nr++;
 			ALLOC_GROW(file_diff->hunk, file_diff->hunk_nr,
 				   file_diff->hunk_alloc);
@@ -207,7 +214,9 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 			if (colored)
 				hunk->colored_start = colored_p - colored->buf;
 
-			if (parse_hunk_header(s, hunk) < 0)
+			if (deleted)
+				file_diff->deleted = 1;
+			else if (parse_hunk_header(s, hunk) < 0)
 				return -1;
 		}

-- 
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