Re: [BUG] Regression in 'git mergetool --tool-help'

From: René Scharfe <l.s.r@web.de>
Date: Dec 20, 2020, 16:23 UTC
Message-ID: <a9e6f3aa-e88e-6cc2-fb16-c26bdd3bf4d3@web.de>
In-Reply-To: <568f42a0-f630-64ca-9f77-183dcaa56d1e@kdbg.org>

Am 20.12.20 um 11:28 schrieb Johannes Sixt:

Show 32 quoted lines

> Am 20.12.20 um 03:13 schrieb Philippe Blain:
>> Thanks for both answers. Felipe's solution does the trick, but Junio's
>> does not;
>> it seems we do have to have a newline there. The following also works,
>> and I think
>> is portable:
>>
>> diff --git i/git-mergetool--lib.sh w/git-mergetool--lib.sh
>> index 2defef28cd..6f03975493 100644
>> --- i/git-mergetool--lib.sh
>> +++ w/git-mergetool--lib.sh
>> @@ -46,7 +46,7 @@ show_tool_names () {
>>          while read scriptname
>>          do
>>              setup_tool "$scriptname" 2>/dev/null
>> -            variants="$variants$(list_tool_variants)\n"
>> +            variants="$(echo "$variants" && list_tool_variants)"
>>          done
>>          variants="$(echo "$variants" | sort | uniq)"
>>
>> I figured out what was different between the different Ubuntu versions I
>> was testing:
>> the Ubuntu 14 and 18 systems have Bash as /bin/sh, but my Ubuntu 20 system
>> has /usr/bin/dash as /bin/sh (the default for Ubuntu these days).
>>
>> I'll try to send a formal patch with the diff above, time permitting...
>
> If possible, please do not use sub-processes like in your suggested
> patch. How about
>
> 		variants="$variants
> $(list_tool_variants)"

This still starts a subshell in the last line. How about something like this?

diff --git a/git-mergetool--lib.sh b/git-mergetool--lib.sh
index 7225abd811..79d5ed1fa9 100644
--- a/git-mergetool--lib.sh
+++ b/git-mergetool--lib.sh
@@ -46,11 +46,9 @@ show_tool_names () {
 		while read scriptname
 		do
 			setup_tool "$scriptname" 2>/dev/null
-			variants="$variants$(list_tool_variants)\n"
-		done
-		variants="$(echo "$variants" | sort | uniq)"
-
-		for toolname in $variants
+			list_tool_variants
+		done | sort | uniq |
+		while read toolname
 		do
 			if setup_tool "$toolname" 2>/dev/null &&
 				(eval "$condition" "$toolname")

It requires setup_tool to be silent, though.

> It leaves a blank line at the beginning of $variants instead of the end
> and should not make a difference in the outcome of
>
> 	variants="$(echo "$variants" | sort | uniq)"
>
> BTW, is `sort -u` not available everywhere?

It's used by the function mergetool_find_win32_cmd in the same file
and by several test scripts, so that shouldn't be a problem.

René