[PATCH v0 0/4] Remove obsolete Cygwin support from git-gui

git-gui has many snippets of code guarded by an is_Cygwin test, all of which target a problematic hybrid Cygwin/Windows 8.4.1 Tcl/Tk removed in March 2012. That is when Cygwin switched to a well-supported unix/X11 Tcl/Tk package. 64-bit Cygwin was released later so has always had the unix/X11 package. git-gui runs as-is on more recent Cygwin, treating it as a Linux variant, though two functions are disabled.

The old Tcl/Tk understood Windows pathnames, so git-gui's Cygwin specific code uses Windows pathnames. The unix/X11 code requires use of unix pathnames, so none of the Cygwin specific code is compatible, and all should be removed.

Fortunately, the is_Cygwin funcion in git-gui (on the git master branch) relies upon the old Tcl/Tk and doesn't detect Cygwin. But, commit c5766eae6f2b002396b6cd4f85b62317b707174e on the git-gui master branch "fixed" is_Cygwin, enabling the incompatible code, so upstream git-gui is now broken on Cygwin.

There is Cygwin specific code in the Makefile, intended to allow a completely unsupported configuration with a Windows TclTk. This code misdetects the configuration, creating a non-portable installation. The Cygwin git maintainer comments this code out. The code should be removed.

The existing code for file browsing and creating a desktop icon is shared with Git For Windows support, and uses Windows pathnames. This code does not work on Cygwin, and needs replacement. These functions have not worked since 2012.

patch 1 removes the obsolete Makefile code patch 2 removes all obsolete git-gui.sh code, wrapped in is_Cygwin... patch 3 implements Cygwin specific file browsing support patch 4 implemetns Cygwin specific desktop icon support

Patches 1/2 cause git-gui to function as it has for the last decade on Cygwin, but without bugs masking bugs. Patches 3/4 restore functionality lost with the Tcl/Tk switch in 2012.

Any argument for keeping the old Cygwin code must address who is going to test and maintain that code, on what platform, and who the target audience is. The old Tcl/Tk was only on 32-bit Cygwin and only supported for the Insight debugger, 32-bit Cygwin is no longer supported, git-gui is not supported on 8.4.1 Tcl/Tk, and the Windows versions targeted by 2012'ish 32-bit Cygwin are no longer supported.

Mark Levedahl (4):
  git gui Makefile - remove Cygwin modiifications
  git-gui - remove obsolete Cygwin specific code
  git-gui - use cygstart to browse on Cygwin
  git-gui - use mkshortcut on Cygwin

 Makefile                  |  21 +------
 git-gui.sh                | 126 ++++----------------------------------
 lib/choose_repository.tcl |  27 +-------
 lib/shortcut.tcl          |  31 +++++-----
 4 files changed, 31 insertions(+), 174 deletions(-)