[PATCH v1 06/11] git gui: GIT_DIR / GIT_WORK_TREE make any discovery error fatal

[Mark Levedahl <mlevedahl@gmail.com>]

git accepts any combination of GIT_DIR and GIT_WORK_TREE to override the
normal repository and worktree discovery process.  git-gui should accept
any such valid configuration, but overriding the discovery process means
the user has assured that the combination of current directory, GIT_DIR,
and GIT_WORK_TREE will lead to the correct repository and worktree. As
such, an error found during discovery where either or both of GIT_DIR
and GIT_WORK_TREE are set is a fatal error, no further exploration
should be tried.

Provide a common proc to support displaying an error message and exiting
if GIT_DIR or GIT_WORK_TREE are in the environment.

Signed-off-by: Mark Levedahl <mlevedahl@gmail.com>
---
 git-gui.sh | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/git-gui.sh b/git-gui.sh
index c2cf5f1..2e2ddc0 100755
--- a/git-gui.sh
+++ b/git-gui.sh
@@ -1122,6 +1122,24 @@ unset argv0dir
 ##
 ## repository setup
 
+proc is_gitvars_error {err} {
+	set havevars 0
+	set GIT_DIR {}
+	set GIT_WORK_TREE {}
+	catch {set GIT_DIR $::env(GIT_DIR); set havevars 1}
+	catch {set GIT_WORK_TREE $::env(GIT_WORK_TREE) ; set havevars 1}
+
+	if {$havevars} {
+		catch {wm withdraw .}
+		error_popup [strcat [mc "Invalid configuration:"] \
+		   "\n" "GIT_DIR: " $GIT_DIR \
+		   "\n" "GIT_WORK_TREE: " $GIT_WORK_TREE \
+			"\n\n$err"]
+		return 1
+	}
+	return 0
+}
+
 proc set_gitdir_vars {} {
 	global _gitdir _gitworktree env
 	if {$_gitdir ne {}} {
-- 
2.54.0.99.14