[PATCH] mergetools/meld: Use --help output to detect --output support
- From
Jonathan Nieder <jrnieder@gmail.com>
- Date
- Feb 10, 2012, 21:57 UTC
- Message-ID
- <20120210215755.GL19216@burratino>
- In-Reply-To
- <7vwr7unzs8.fsf@alter.siamese.dyndns.org>
In v1.7.7-rc0~3^2 (2011-08-19), git mergetool's "meld" support learned to use the --output option when calling versions of meld that are detected to support it (1.5.0 and newer, hopefully).
Alas, it misdetects old versions (before 1.1.5, 2006-06-11) of meld as supporting the option, so on systems with such meld, instead of getting a nice merge helper, the operator gets a dialog box with the text "Wrong number of arguments (Got 5)". (Version 1.1.5 is when meld switched to using optparse. One consequence of that change was that errors in usage are detected and signalled through the exit status even when --help was passed.)
Luckily there is a simpler check that is more reliable: the usage string printed by "meld --help" reliably reflects whether --output is supported in a given version. Use it.
Reported-by: Jeff Epler <jepler@unpythonic.net> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> --- Junio C Hamano wrote:
> When an older meld fails when given --output for real (not with the dry > run current code tries with --help), can we sanely detect that particular > failure?
Unfortunately it just pops up a GUI with a modal dialog box like this: ___________________________________ | | | Wrong number of arguments (Got 5) | | | | [Quit] [OK] | |___________________________________|
If I choose "Quit", the exit status is 0.
But how about this? "meld --help | grep -e --output" seems to detect support for the option reliably. With 2>&1 on the upstream of the pipe, this even seems futureproof. ;-)
mergetools/meld | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/mergetools/meld b/mergetools/meld index eaa115cc..cb672a55 100644 --- a/mergetools/meld +++ b/mergetools/meld @@ -23,7 +23,7 @@ check_meld_for_output_version () { meld_path="$(git config mergetool.meld.path)" meld_path="${meld_path:-meld}" - if "$meld_path" --output /dev/null --help >/dev/null 2>&1 + if "$meld_path" --help 2>&1 | grep -e --output >/dev/null then meld_has_output_option=true else
-- 1.7.9