completion: fix completion after 'git --option <TAB>'

The bash completion doesn't work when certain options to git itself are specified, e.g. 'git --no-pager <TAB>' errors out with error: invalid key: alias.--no-pager The main _git() completion function finds out the git command name by looping through all the words on the command line and searching for the first word that is not a known option for the git command. Unfortunately the list of known git options was not updated in a long time, and newer options are not skipped but mistaken for a git command. Such a misrecognized "command" is then passed to __git_aliased_command(), which in turn passes it to a 'git config' query, hence the error. Currently the following options are misrecognized for a git command: -c --no-pager --exec-path --html-path --man-path --info-path --no-replace-objects --work-tree= --namespace= To fix this we could just update the list of options to be skipped, but the same issue will likely arise, if the git command learns a new option in the future. Therefore, to make it more future proof against new options, this patch changes that loop to skip all option-looking words, i.e. words starting with a dash. We also have to handle the '-c' option specially, because it takes a configutation parameter in a separate word, which must be skipped, too. [fc: added tests] Signed-off-by: SZEDER Gábor <szeder@ira.uka.de> Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>