Why doesn't git-fetch obey -c "remote.origin.url" on the command-line?

On a git built from the master branch just now:

 $ ./git config remote.origin.url
https://code.google.com/p/git-core/
$ ./git -c remote.origin.url=git://git.sourceforge.jp/gitroot/git-core/git.git
config remote.origin.url
git://git.sourceforge.jp/gitroot/git-core/git.git
$ GIT_TRACE=1 ./git -c
remote.origin.url=git://git.sourceforge.jp/gitroot/git-core/git.git
fetch 2>&1 | head -n 2
trace: built-in: git 'fetch'
trace: run_command: 'git-remote-https' 'origin'
'https://code.google.com/p/git-core/'

I'd expect this to try to fetch from the remote.origin.url I specified on the command-line, but for some reason fetch doesn't pick that up. Isn't this a bug?

The use case for this is to have a script in cron that does a pull of repositories via http while the developers expecting to occasionally use those repositories as work directories should transparently be able to pull/push from them.

I know about remote.origin.pushurl, but I'd prefer pulls to also be over ssh in those cases, because then you don't have to worry about proxy settings (different for the devs & that automated script).

I could fix this, but I thought I'd first send a question about whether this shouldn't be considered a bug, and I haven't dug into this yet but I think that configuration passed via the -c option should *always* override any other config Git may get from elsewhere.

On Fri, Jun 13, 2014 at 09:37:07AM +0200, Ævar Arnfjörð Bjarmason wrote:

I think this is an alternate version of the report in [1].

The short answer is: remote.*.url is a multi-valued config option, and you can only append to (not override) such options with "git -c". Try using insteadOf.

-Peff

[1] http://article.gmane.org/gmane.comp.version-control.git/250427

From: "Jeff King" <peff@peff.net>

If anything, given Peff's clarification below, it's a bug in the way the documentation has (not) communicated this trap for the unwary.

The question would then become "What warning should be given and where should it/they be placed?" It should go within the documentation where folk look to check that the command innvocations were as expected. (It may also be a 'common knowledge' issue [2]).

I already see that the git(1) man page for the '-c' option doesn't cover the mult-value config option case.

The config-api suggests the common priority order where later values override newer values.

I've done a little documentation patch to cover the current situation.

I've also copied in Robert (fuz) (from [1]) and Tanay (updating the reading of config files).

[2] "It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so." Mark Twain