Subject: Re: [PATCH] t9001: avoid not portable '\n' with sed

From: Junio C Hamano <[email-masked]>
Date: Wed, 04 Jun 2014 11:13:47 -0700

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

> Torsten Bögershausen <[email-masked]> writes:
>
>> t9001 used a '\n' in a sed expression to split one line into two lines.
>> Some versions of sed simply ignore the '\' before the 'n', treating
>> '\n' as 'n'.
>>
>> As the test already requires perl as a prerequisite, use perl instead of sed.
>>
>> Signed-off-by: Torsten Bögershausen <[email-masked]>
>> ---
>
> Hmph.  I read this in pubs.opengroup.org/onlinepubs/9699919799/utilities/sed.html
>
>     The escape sequence '\n' shall match a <newline> embedded in the
>     pattern space.
>
> so it may be better to be a bit more explicit in the log message to
> say whose implementation has this issue to warn people.
>
>>  t/t9001-send-email.sh | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/t/t9001-send-email.sh b/t/t9001-send-email.sh
>> index 64d9434..2bf48d1 100755
>> --- a/t/t9001-send-email.sh
>> +++ b/t/t9001-send-email.sh
>> @@ -1342,7 +1342,7 @@ test_cover_addresses () {
>>  	git format-patch --cover-letter -2 -o outdir &&
>>  	cover=`echo outdir/0000-*.patch` &&
>>  	mv $cover cover-to-edit.patch &&
>> -	sed "s/^From:/$header: [email-masked]\nFrom:/" cover-to-edit.patch >"$cover" &&
>> +	"$PERL_PATH" -pe "s/^From:/$header: extra\@address.com\nFrom:/" cover-to-edit.patch | tr Q "$LF" >"$cover" &&
>
> We have a shell function "perl" in test-lib-function.sh these days
> so that you do not have to write "$PERL_PATH" yourself in tests ;-)

Also, piping output from perl to tr feels somewhat suboptimal.  I do
not see where in the test material we use "Q to LF", and we may want
to remove that altogether, but without that removal, an updated
patch may look like this.

 t/t9001-send-email.sh | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/t/t9001-send-email.sh b/t/t9001-send-email.sh
index 64d9434..9f06b8c 100755
--- a/t/t9001-send-email.sh
+++ b/t/t9001-send-email.sh
@@ -1342,7 +1342,10 @@ test_cover_addresses () {
 	git format-patch --cover-letter -2 -o outdir &&
 	cover=`echo outdir/0000-*.patch` &&
 	mv $cover cover-to-edit.patch &&
-	sed "s/^From:/$header: [email-masked]\nFrom:/" cover-to-edit.patch >"$cover" &&
+	perl -pe "
+		s/^From:/$header: extra\@address.com\nFrom:/;
+		y/Q/\n/;
+	" cover-to-edit.patch >"$cover" &&
 	git send-email \
 	  --force \
 	  --from="Example <[email-masked]>" \