Re: [PATCH v2 1/2] osxkeychain: lock for exclusive execution

[Junio C Hamano <gitster@pobox.com>]

"Koji Nakamaru via GitGitGadget" <gitgitgadget@gmail.com> writes:

> From: Koji Nakamaru <koji.nakamaru@gree.net>
>
> Resolves "failed to store: -25299" when "fetch.parallel 0" is configured
> and there are many submodules.

Use of third-person singular without subject for the "observation"
part is highly unusual the log messages in our codebase.

The usual way to compose a log message of this project is to

 - Give an observation on how the current system work in the present
   tense (so no need to say "Currently X is Y", just "X is Y"), and
   discuss what you perceive as a problem in it.

 - Propose a solution (optional---often, problem description
   trivially leads to an obvious solution in reader's minds).

 - Give commands to the codebase to "become like so".

in this order.

> The error code -25299 (errSecDuplicateItem) may be returned by
> SecItemUpdate() in add_internet_password() if multiple instances of
> git-credential-osxkeychain run in parallel. This patch introduces an
> exclusive lock to serialize execution for avoiding this and other
> potential issues.

"This patch introduces" -> "Introduce"

Is this step still needed, though?

> Signed-off-by: Koji Nakamaru <koji.nakamaru@gree.net>
> ---
>  contrib/credential/osxkeychain/git-credential-osxkeychain.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/contrib/credential/osxkeychain/git-credential-osxkeychain.c b/contrib/credential/osxkeychain/git-credential-osxkeychain.c
> index 6a40917b1ef..0884db48d0a 100644
> --- a/contrib/credential/osxkeychain/git-credential-osxkeychain.c
> +++ b/contrib/credential/osxkeychain/git-credential-osxkeychain.c
> @@ -414,6 +414,9 @@ int main(int argc, const char **argv)
>  	if (!argv[1])
>  		die("%s", usage);
>  
> +	if (open(argv[0], O_RDONLY | O_EXLOCK) == -1)
> +		die("failed to lock %s", argv[0]);
> +
>  	read_credential();
>  
>  	if (!strcmp(argv[1], "get"))