patchgit-gui: allow opening work trees from the startup dialog

> From: Mikhail Terekhov <termim@gmail.com>
> 
> In proc _is_git check that supplied path is a valid work tree path.
> This allows the choose_repository::pick dialog to accept path to a
> work tree directory.

> Signed-off-by: Mikhail Terekhov <termim@gmail.com>
> ---
>     git-gui: allow opening work trees from the startup dialog
>     
>     Trying to open a working tree from the "Open Existing Repository" link
>     of the git-gui startup dialog results in an error: Not a Git repository:
>     .... This patch fixes that error.
> 
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-644%2Ftermim%2Fgit-gui-open-worktree-v1
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-644/termim/git-gui-open-worktree-v1
> Pull-Request: https://github.com/gitgitgadget/git/pull/644
> 
>  lib/choose_repository.tcl | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/lib/choose_repository.tcl b/lib/choose_repository.tcl
> index e54f3e66d8f..8f911e89fbb 100644
> --- a/lib/choose_repository.tcl
> +++ b/lib/choose_repository.tcl
> @@ -362,8 +362,19 @@ proc _is_git {path {outdir_var ""}} {
>  		gets $fp line
>  		close $fp
>  		if {[regexp "^gitdir: (.+)$" $line line link_target]} {
> +			set check_path [file normalize $path]
>  			set path [file join [file dirname $path] $link_target]
>  			set path [file normalize $path]
> +

> +			if {[file exists [file join $path gitdir]]} {
> +				set fp [open [file join $path gitdir] r]
> +				gets $fp worktree_path
> +				close $fp
> +				if {[string equal $check_path $worktree_path]} {
> +					set outdir $path
> +					return 1
> +				}
> +			}

> On 26/05/20 03:33PM, Mikhail Terekhov via GitGitGadget wrote:
> > From: Mikhail Terekhov <termim@gmail.com>
> > +                     if {[file exists [file join $path gitdir]]} {
> > +                             set fp [open [file join $path gitdir] r]
> > +                             gets $fp worktree_path
> > +                             close $fp
> > +                             if {[string equal $check_path $worktree_path]} {
> > +                                     set outdir $path
> > +                                     return 1
> > +                             }
> > +                     }
>
> I wonder if there is a way of finding if the path is a worktree path
> using a Git plumbing command. That IMO would be better than rolling our
> own logic to check if something is a worktree.

> From: Mikhail Terekhov <termim@gmail.com>
> 
> In proc _is_git check that supplied path is a valid work tree path.
> This allows the choose_repository::pick dialog to accept path to a
> work tree directory.
> 
> Signed-off-by: Mikhail Terekhov <termim@gmail.com>
> ---
>  lib/choose_repository.tcl | 29 +++++------------------------
>  1 file changed, 5 insertions(+), 24 deletions(-)
> 
> diff --git a/lib/choose_repository.tcl b/lib/choose_repository.tcl
> index e54f3e66d8f..07f29b0b13b 100644
> --- a/lib/choose_repository.tcl
> +++ b/lib/choose_repository.tcl
> @@ -357,31 +357,12 @@ proc _is_git {path {outdir_var ""}} {
>  	if {$outdir_var ne ""} {
>  		upvar 1 $outdir_var outdir
>  	}
> -	if {[file isfile $path]} {
> -		set fp [open $path r]
> -		gets $fp line
> -		close $fp
> -		if {[regexp "^gitdir: (.+)$" $line line link_target]} {
> -			set path [file join [file dirname $path] $link_target]
> -			set path [file normalize $path]
> -		}
> -	}
> -
> -	if {[file exists [file join $path HEAD]]
> -	 && [file exists [file join $path objects]]
> -	 && [file exists [file join $path config]]} {
> -		set outdir $path
> -		return 1
> -	}
> -	if {[is_Cygwin]} {
> -		if {[file exists [file join $path HEAD]]
> -		 && [file exists [file join $path objects.lnk]]
> -		 && [file exists [file join $path config.lnk]]} {
> -			set outdir $path
> -			return 1
> -		}
> +	if {[catch { 
> +		set outdir [git rev-parse --resolve-git-dir $path] 
> +		} ]} {
> +			return 0

> +Cc Eric.
> 
> On 06/06/20 04:33AM, Mikhail Terekhov via GitGitGadget wrote:
> > From: Mikhail Terekhov <termim@gmail.com>
> > 
> > In proc _is_git check that supplied path is a valid work tree path.
> > This allows the choose_repository::pick dialog to accept path to a
> > work tree directory.
> > 
> > Signed-off-by: Mikhail Terekhov <termim@gmail.com>
> > ---
> >  lib/choose_repository.tcl | 29 +++++------------------------
> >  1 file changed, 5 insertions(+), 24 deletions(-)
> > 
> > diff --git a/lib/choose_repository.tcl b/lib/choose_repository.tcl
> > index e54f3e66d8f..07f29b0b13b 100644
> > --- a/lib/choose_repository.tcl
> > +++ b/lib/choose_repository.tcl
> > @@ -357,31 +357,12 @@ proc _is_git {path {outdir_var ""}} {
> >  	if {$outdir_var ne ""} {
> >  		upvar 1 $outdir_var outdir
> >  	}
> > -	if {[file isfile $path]} {
> > -		set fp [open $path r]
> > -		gets $fp line
> > -		close $fp
> > -		if {[regexp "^gitdir: (.+)$" $line line link_target]} {
> > -			set path [file join [file dirname $path] $link_target]
> > -			set path [file normalize $path]
> > -		}
> > -	}
> > -
> > -	if {[file exists [file join $path HEAD]]
> > -	 && [file exists [file join $path objects]]
> > -	 && [file exists [file join $path config]]} {
> > -		set outdir $path
> > -		return 1
> > -	}
> > -	if {[is_Cygwin]} {
> > -		if {[file exists [file join $path HEAD]]
> > -		 && [file exists [file join $path objects.lnk]]
> > -		 && [file exists [file join $path config.lnk]]} {
> > -			set outdir $path
> > -			return 1
> > -		}
> > +	if {[catch { 
> > +		set outdir [git rev-parse --resolve-git-dir $path] 
> > +		} ]} {
> > +			return 0
> 
> I fixed trailing whitespace in a couple lines and a small style nitpick. You 
> can check them here [0]. Will merge. Thanks both.
> 
> [0] https://github.com/prati0100/git-gui/commit/79089e52643ce1ba7d8494f32b2fb1891c926079