Re: [PATCH] use strbuf_addstr() for adding constant strings to a strbuf, part 2

Am 15.09.2016 um 22:01 schrieb Junio C Hamano:

René Scharfe [off-list ref] writes:

quoted

Take this for example:

-			strbuf_addf(&o->obuf, _("(bad commit)\n"));
+			strbuf_addstr(&o->obuf, _("(bad commit)\n"));

If there's a language that uses percent signs instead of parens or as
regular letters, then they need to be escaped in the translated string
before, but not after the patch.  As I wrote: silly.

Ahh, OK, so "This use of addf only has format part and nothing else,
hence the format part can be taken as-is" which is the Coccinelle rule
used to produce this patch is incomplete and always needs manual
inspection, in case the format part wanted to give a literal % in
the output.  E.g. it is a bug to convert this

	strbuf_addf(&buf, _("this is 100%% wrong!"));

to

	strbuf_addstr(&buf, _("this is 100%% wrong!"));

Right.  Such strings seem to be quite rare in practice, though. 

Thanks for clarification.  Perhaps the strbuf.cocci rule file can
have some comment to warn the person who builds *.patch file to look
for % in E2, or something?

Something like this?

---
 contrib/coccinelle/strbuf.cocci | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/contrib/coccinelle/strbuf.cocci b/contrib/coccinelle/strbuf.cocci
index 7932d48..3f535ca 100644
--- a/contrib/coccinelle/strbuf.cocci
+++ b/contrib/coccinelle/strbuf.cocci

@@ -1,3 +1,5 @@
+// Careful, this is not fully equivalent: "%" is no longer treated
+// specially.  Check for "%%", "%m" etc. in the format string (E2).
 @@
 expression E1, E2;
 @@

-- 
2.10.0