Subject: Re: Is there a way to get the "format-patch" formatted file name?

From: Junio C Hamano <[email-masked]>
Date: Fri, 01 Sep 2023 09:04:15 -0700

Junio C Hamano <[email-masked]> writes:

> We can just invent a new label (e.g. "Filesystem-safe-subject:"),
> pass the subject string to pretty.c:format_sanitized_subject() and
> emit the result next to the existing "Subject:" with that label, and
> we can even do so unconditionally without breaking anybody.

Such a change would be quite small and simple.

 mailinfo.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git c/mailinfo.c w/mailinfo.c
index 931505363c..b0eb646f4e 100644
--- c/mailinfo.c
+++ w/mailinfo.c
@@ -5,6 +5,7 @@
 #include "utf8.h"
 #include "strbuf.h"
 #include "mailinfo.h"
+#include "pretty.h"
 
 static void cleanup_space(struct strbuf *sb)
 {
@@ -1166,11 +1167,16 @@ static void handle_info(struct mailinfo *mi)
 		}
 
 		if (!strcmp(header[i], "Subject")) {
+			struct strbuf san = STRBUF_INIT;
+
 			if (!mi->keep_subject) {
 				cleanup_subject(mi, hdr);
 				cleanup_space(hdr);
 			}
 			output_header_lines(mi->output, "Subject", hdr);
+			format_sanitized_subject(&san, hdr->buf, hdr->len);
+			output_header_lines(mi->output, "Filesystem-Safe-Subject", &san);
+			strbuf_release(&san);
 		} else if (!strcmp(header[i], "From")) {
 			cleanup_space(hdr);
 			handle_from(mi, hdr);