git-gui: Allow gitk to be started on Cygwin with native Tcl/Tk

diff --git a/git-gui.sh b/git-gui.sh
index c8375029dd35964bb299b87612b4978cdcfda85b..9682418e1225499caf99151e8a91968cdb106c2c 100755 (executable)
--- a/git-gui.sh
+++ b/git-gui.sh
@@ -1468,7 +1468,27 @@ proc do_gitk {revs} {
        if {! [file exists $exe]} {
                error_popup "Unable to start gitk:\n\n$exe does not exist"
        } else {
+               global env
+
+               if {[info exists env(GIT_DIR)]} {
+                       set old_GIT_DIR $env(GIT_DIR)
+               } else {
+                       set old_GIT_DIR {}
+               }
+
+               set pwd [pwd]
+               cd [file dirname [gitdir]]
+               set env(GIT_DIR) [file tail [gitdir]]
+
                eval exec $cmd $revs &
+
+               if {$old_GIT_DIR eq {}} {
+                       unset env(GIT_DIR)
+               } else {
+                       set env(GIT_DIR) $old_GIT_DIR
+               }
+               cd $pwd
+
                ui_status $::starting_gitk_msg
                after 10000 {
                        ui_ready $starting_gitk_msg