[PATCH 5/7] worktree: `list` escape lock reason in --porcelain

[Rafael Silva <rafaeloliveira.cs@gmail.com>]

"git worktree list" porcelain format shows one attribute per line, each
attribute is listed with a label and value separated by a single space.
If any worktree is locked, a "locked" attribute is listed followed by the
reason, if available, otherwise only "locked" is shown.

In case the lock reason contains newline characters (i.e: LF or CRLF)
this will cause the format to break as each line should correspond to
one attribute. This leads to unwanted behavior, specially as the
porcelain is intended to be machine-readable. To address this shortcoming
let's teach "git worktree list" to escape any newline character before
outputting the locked reason for porcelain format.

Signed-off-by: Rafael Silva <rafaeloliveira.cs@gmail.com>
---
 builtin/worktree.c | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/builtin/worktree.c b/builtin/worktree.c
index dedd4089e5..9156ccd67e 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -567,6 +567,24 @@ static int add(int ac, const char **av, const char *prefix)
 	return add_worktree(path, branch, &opts);
 }
 
+static char *worktree_escape_reason(char *reason)
+{
+	struct strbuf escaped = STRBUF_INIT;
+	char *r;
+
+	for (r = reason; *r; r++) {
+		if (*r == '\r' && *(r + 1) && *(r + 1) == '\n') {
+			strbuf_addstr(&escaped, "\\r\\n");
+			r++;
+		} else if (*r == '\n')
+			strbuf_addstr(&escaped, "\\n");
+		else
+			strbuf_addch(&escaped, *r);
+	}
+
+	return strbuf_detach(&escaped, NULL);
+}
+
 static void show_worktree_porcelain(struct worktree *wt)
 {
 	printf("worktree %s\n", wt->path);
@@ -580,9 +598,11 @@ static void show_worktree_porcelain(struct worktree *wt)
 			printf("branch %s\n", wt->head_ref);
 
 		if (worktree_lock_reason(wt)) {
-			if (*wt->lock_reason)
-				printf("locked %s\n", wt->lock_reason);
-			else
+			if (*wt->lock_reason) {
+				char *reason = worktree_escape_reason(wt->lock_reason);
+				printf("locked %s\n", reason);
+				free(reason);
+			} else
 				printf("locked\n");
 		}
 
-- 
2.30.0.391.g469bf2a980