Re: [PATCH] checkout: Don't crash when switching away from an invalid branch.

Johannes Schindelin [off-list ref] writes:

quoted

diff --git a/builtin-checkout.c b/builtin-checkout.c
index 57b94d2..7c1b8cd 100644
--- a/builtin-checkout.c
+++ b/builtin-checkout.c

@@ -47,7 +47,8 @@ static int post_checkout_hook(struct commit *old, struct commit *new,
 
 	memset(&proc, 0, sizeof(proc));
 	argv[0] = name;
-	argv[1] = xstrdup(sha1_to_hex(old->object.sha1));
+	argv[1] = old ? xstrdup(sha1_to_hex(old->object.sha1))
+		      : "0000000000000000000000000000000000000000";

I guess you want to use the variable null_sha1 here.

I could, though it seemed to me a bit silly to format and strdup a
string that is a known constant. But I'm happy to change it if needed.

quoted

@@ -492,10 +493,13 @@ static void update_refs_for_switch(struct checkout_opts *opts,
 	}
 
 	old_desc = old->name;
-	if (!old_desc)
+	if (!old_desc && old->commit)
 		old_desc = sha1_to_hex(old->commit->object.sha1);
-	strbuf_addf(&msg, "checkout: moving from %s to %s",
-		    old_desc, new->name);
+	if (old_desc)
+		strbuf_addf(&msg, "checkout: moving from %s to %s",
+			    old_desc, new->name);
+	else
+		strbuf_addf(&msg, "checkout: moving to %s", new->name);

Why not
		old_desc ? old_desc : "(invalid)"
?

IMO it looks more friendly to not display a branch that doesn't exist,
rather than printing something like (invalid) or (null).

-- 
Alexandre Julliard
julliard@winehq.org