Re: [PATCH] git-gui: msys2 compatibility patches

From: Pratyush Yadav <me@yadavpratyush.com>
Date: Apr 27, 2020, 19:45 UTC
Message-ID: <20200427194546.7ce4z2ooe4jaab5w@yadavpratyush.com>
In-Reply-To: <pull.612.git.1586900734341.gitgitgadget@gmail.com>

Hi Konstantin,

Thanks for the patch, and sorry for the late reply.

On 14/04/20 09:45PM, Konstantin Podsvirov via GitGitGadget wrote:

> From: Konstantin Podsvirov <konstantin@podsvirov.pro>
> 
> Allow using `git gui` command via MSYS2's MINGW32/64 subsystems (apropriate shells).

I think this should be the commit subject, instead of "msys2 
compatibility patches".

Show 15 quoted lines

> Just install apropriate `tk` package:
> 
> ```bash
> user@host MINGW32 ~
> pacman -S mingw-w64-i686-tk
> ```
> 
> or
> 
> ```bash
> user@host MINGW64 ~
> pacman -S mingw-w64-x86_64-tk
> ```
> 
> For more info see: https://github.com/msys2/MSYS2-packages/pull/1912

Please don't just link to an external website. Put the explanation there 
in the commit message. Explain what the problem was, and how this patch 
fixes it.

Show 51 quoted lines

> Signed-off-by: Konstantin Podsvirov <konstantin@podsvirov.pro>
> ---
>  git-gui.sh | 52 ++++++++++++++++++++++++++++++----------------------
>  1 file changed, 30 insertions(+), 22 deletions(-)
> 
> diff --git a/git-gui.sh b/git-gui.sh
> index 4610e4ca72a..512f4f121aa 100755
> --- a/git-gui.sh
> +++ b/git-gui.sh
> @@ -44,6 +44,28 @@ if {[catch {package require Tcl 8.5} err]
>  
>  catch {rename send {}} ; # What an evil concept...
>  
> +######################################################################
> +##
> +## platform detection
> +
> +set _iscygwin {}
> +
> +proc is_Cygwin {} {
> +	global _iscygwin
> +	if {$_iscygwin eq {}} {
> +		if {$::tcl_platform(platform) eq {windows}} {
> +			if {[catch {set p [exec cygpath --windir]} err]} {
> +				set _iscygwin 0
> +			} else {
> +				set _iscygwin 1
> +			}
> +		} else {
> +			set _iscygwin 0
> +		}
> +	}
> +	return $_iscygwin
> +}
> +
>  ######################################################################
>  ##
>  ## locate our library
> @@ -51,7 +73,14 @@ catch {rename send {}} ; # What an evil concept...
>  if { [info exists ::env(GIT_GUI_LIB_DIR) ] } {
>  	set oguilib $::env(GIT_GUI_LIB_DIR)
>  } else {
> -	set oguilib {@@GITGUI_LIBDIR@@}
> +	if {[is_Cygwin]} {
> +		set oguilib [exec cygpath \
> +			--windows \
> +			--absolute \
> +			@@GITGUI_LIBDIR@@]
> +	} else {
> +		set oguilib {@@GITGUI_LIBDIR@@}
> +	}

This would convert the Windows style path to a Unix style path if we are running in Cygwin, right? This is what I assume the heart of the problem is.

Style nitpick: something like this would probably be better:

  set oguilib {@@GITGUI_LIBDIR@@}
  if {[is_Cygwin]} {
	...
  }

This makes it clear that Cygwin is the exception. For all other cases, we want to use @@GITGUI_LIBDIR@@ directly.

Show 8 quoted lines

>  }
>  set oguirel {@@GITGUI_RELATIVE@@}
>  if {$oguirel eq {1}} {
> @@ -163,7 +192,6 @@ set _isbare {}
>  set _gitexec {}
>  set _githtmldir {}
>  set _reponame {}
> -set _iscygwin {}

Why move the initialization?

Show 19 quoted lines

>  set _search_path {}
>  set _shellpath {@@SHELL_PATH@@}
>  
> @@ -266,26 +294,6 @@ proc is_Windows {} {
>  	return 0
>  }
>  
> -proc is_Cygwin {} {
> -	global _iscygwin
> -	if {$_iscygwin eq {}} {
> -		if {$::tcl_platform(platform) eq {windows}} {
> -			if {[catch {set p [exec cygpath --windir]} err]} {
> -				set _iscygwin 0
> -			} else {
> -				set _iscygwin 1
> -				# Handle MSys2 which is only cygwin when MSYSTEM is MSYS.
> -				if {[info exists ::env(MSYSTEM)] && $::env(MSYSTEM) ne "MSYS"} {
> -					set _iscygwin 0
> -				}

I'm afraid I don't understand this hunk. I don't use Windows, and don't completely understand the difference between cygwin, msys, etc. Could you please explain further why this check is removed? Are there any negative side-effects?

Show 8 quoted lines

> -			}
> -		} else {
> -			set _iscygwin 0
> -		}
> -	}
> -	return $_iscygwin
> -}
> -

Why move the function? Can't this and the _iscygwin initialization just stay in their place? It will make the diff much easier to read.

>  proc is_enabled {option} {
>  	global enabled_options
>  	if {[catch {set on $enabled_options($option)}]} {return 0}

-- 
Regards,
Pratyush Yadav