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contrib/completion/git-completion.bash: declare -g is not portable

Subject: contrib/completion/git-completion.bash: declare -g is not portable

## tl;dr

6 messages between Feb 3, 2018 and Feb 4, 2018.

replies: 5people: 6as markdown or json

Torsten Bögershausen· Feb 3, 2018, 17:20 UTC · lore

Hej Duy, After running t9902-completion.sh on Mac OS I got a failure in this style:

.../projects/git/git.pu/t/../contrib/completion/git-completion.bash: line 300: declare: -g: invalid option declare: usage: declare [-afFirtx] [-p] [name[=value] ...] --- expected 2018-02-03 17:10:18.000000000 +0000 +++ out 2018-02-03 17:10:18.000000000 +0000

@@ -1,15 +1,2 @@
---quiet
---detach
---track
---orphan=
---ours
---theirs
---merge
---conflict=
---patch
---ignore-skip-worktree-bits
---ignore-other-worktrees
---recurse-submodules
---progress
 --no-track
 --no-recurse-submodules
not ok 92 - double dash "git checkout"

What is "declare -g" good for ?

<https://www.gnu.org/software/bash/manual/html_node/Bash-Builtins.html#index-declare>
Andreas Schwab· Feb 3, 2018, 19:51 UTC · re: Torsten Bögershausen · lore

Re: contrib/completion/git-completion.bash: declare -g is not portable

On Feb 03 2018, Torsten Bögershausen <tboegi@web.de> wrote:
> What is "declare -g" good for ?
      -g        create global variables when used in a shell function; otherwise
                ignored
    When used in a function, `declare' makes NAMEs local, as with the `local'
    command.  The `-g' option suppresses this behavior.
    
Andreas.
-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."
Jeff King· Feb 3, 2018, 20:22 UTC · re: Andreas Schwab · lore

Re: contrib/completion/git-completion.bash: declare -g is not portable

On Sat, Feb 03, 2018 at 08:51:16PM +0100, Andreas Schwab wrote:
Show 9 quoted lines
> On Feb 03 2018, Torsten Bögershausen <tboegi@web.de> wrote:
> 
> > What is "declare -g" good for ?
> 
>       -g        create global variables when used in a shell function; otherwise
>                 ignored
> 
>     When used in a function, `declare' makes NAMEs local, as with the `local'
>     command.  The `-g' option suppresses this behavior.

I think the bigger question is why one would use "declare -g" instead of just assigning the variable with "var=value".

Glancing at the code, I suspect it is because the name of the variable itself needs expanded. If that's the case, we could use eval instead, like:

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 3cc815be0d..204d620ff7 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -297,7 +297,7 @@ __gitcomp_builtin ()
 	eval "options=\$$var"
 
 	if [ -z "$options" ]; then
-		declare -g "$var=$(__git ${cmd/_/ } --git-completion-helper)"
+		eval "$var=\$(__git \${cmd/_/ } --git-completion-helper)"
 		eval "options=\$$var"
 	fi
 

-Peff
Duy Nguyen· Feb 4, 2018, 09:45 UTC · re: Torsten Bögershausen · lore

Re: contrib/completion/git-completion.bash: declare -g is not portable

On Sun, Feb 4, 2018 at 12:20 AM, Torsten Bögershausen <tboegi@web.de> wrote:
> Hej Duy,
> After running t9902-completion.sh on Mac OS I got a failure
> in this style:

Sorry I was new with this bash thingy. Jeff already answered this (and I will fix it in the re-roll) but just for my own information, what bash version is shipped with Mac OS?

-- 
Duy
Eric Sunshine· Feb 4, 2018, 09:57 UTC · re: Duy Nguyen · lore

Re: contrib/completion/git-completion.bash: declare -g is not portable

On Sun, Feb 4, 2018 at 4:45 AM, Duy Nguyen <pclouds@gmail.com> wrote:
Show 7 quoted lines
> On Sun, Feb 4, 2018 at 12:20 AM, Torsten Bögershausen <tboegi@web.de> wrote:
>> After running t9902-completion.sh on Mac OS I got a failure
>> in this style:
>
> Sorry I was new with this bash thingy. Jeff already answered this (and
> I will fix it in the re-roll) but just for my own information, what
> bash version is shipped with Mac OS?
The MacOS bash is very old; note the copyright date:
    % /bin/bash --version
    GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin16)
    Copyright (C) 2007 Free Software Foundation, Inc.
A recent bash installed manually (not from Apple):
    % /usr/local/bin/bash --version
    GNU bash, version 4.4.18(1)-release (x86_64-apple-darwin16.7.0)
    Copyright (C) 2016 Free Software Foundation, Inc.
Lucas Werkmeister· Feb 4, 2018, 11:48 UTC · re: Eric Sunshine · lore

Re: contrib/completion/git-completion.bash: declare -g is not portable

On 04.02.2018 10:57, Eric Sunshine wrote:
Show 21 quoted lines
> On Sun, Feb 4, 2018 at 4:45 AM, Duy Nguyen <pclouds@gmail.com> wrote:
>> On Sun, Feb 4, 2018 at 12:20 AM, Torsten Bögershausen <tboegi@web.de> wrote:
>>> After running t9902-completion.sh on Mac OS I got a failure
>>> in this style:
>>
>> Sorry I was new with this bash thingy. Jeff already answered this (and
>> I will fix it in the re-roll) but just for my own information, what
>> bash version is shipped with Mac OS?
> 
> The MacOS bash is very old; note the copyright date:
> 
>     % /bin/bash --version
>     GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin16)
>     Copyright (C) 2007 Free Software Foundation, Inc.
> 
> A recent bash installed manually (not from Apple):
> 
>     % /usr/local/bin/bash --version
>     GNU bash, version 4.4.18(1)-release (x86_64-apple-darwin16.7.0)
>     Copyright (C) 2016 Free Software Foundation, Inc.
>

Specifically, Apple ships the latest version of Bash 3.x, which is the last version published under the GPLv2+ – Bash 4.x switched to GPLv3+. Users can install newer Bash versions themselves, e. g. using Homebrew, but that doesn’t help us here.

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