[PATCH v1 10/11] git-gui: improve worktree discovery

[Mark Levedahl <mlevedahl@gmail.com>]

git gui's worktree discovery needs update based upon prior work in this
series. In the normal case, all information we need comes directly from
git rev-parse (--show-toplevel, and --show-prefix). Should this work, we
have a valid worktree and all git gui commands can run.

If not, we need to consider:
- if GIT_DIR or GIT_WORK_TREE are in the environment, just stop as we
  the input configuration was wrong, the user must fix that.
- if we have a browser or blame subcommand, no worktree is needed so
  git-gui can run without.
- using the git repository's parent is a valid worktree (if possible),
  restoring prior behavior.

The current directory should be either the root of the worktree, if one
is found, or the top-level of the git repository.

Make it so. Also, make worktree discover directly follow repository
discovery, reducing the locations that might need error trapping to
catch configuration issues.

Signed-off-by: Mark Levedahl <mlevedahl@gmail.com>
---
 git-gui.sh | 56 ++++++++++++++++++++++--------------------------------
 1 file changed, 23 insertions(+), 33 deletions(-)

diff --git a/git-gui.sh b/git-gui.sh
index e326401..3a83dd5 100755
--- a/git-gui.sh
+++ b/git-gui.sh
@@ -1173,6 +1173,28 @@ if {[catch {
 	}
 }
 
+# find worktree, continue without if not required
+if {[catch {
+	set _gitworktree [git rev-parse --show-toplevel]
+	set _prefix [git rev-parse --show-prefix]
+	cd $_gitworktree
+} err]} {
+	if {[is_gitvars_error $err]} {
+		exit 1
+	}
+	set _gitworktree {}
+	set _prefix {}
+	if {[is_enabled bare]} {
+		cd $_gitdir
+	} elseif {![is_parent_worktree]} {
+		catch {wm withdraw .}
+		error_popup [strcat [mc "Cannot use bare repository:"] "\n\n" $_gitdir]
+		exit 1
+	}
+}
+
+# repository and worktree config are complete, export them
+set_gitdir_vars
 
 # Use object format as hash algorithm (either "sha1" or "sha256")
 set hashalgorithm [git rev-parse --show-object-format]
@@ -1189,37 +1211,8 @@ if {$hashalgorithm eq "sha1"} {
 load_config 0
 apply_config
 
-set _gitworktree [git rev-parse --show-toplevel]
 
-if {$_prefix ne {}} {
-	if {$_gitworktree eq {}} {
-		regsub -all {[^/]+/} $_prefix ../ cdup
-	} else {
-		set cdup $_gitworktree
-	}
-	if {[catch {cd $cdup} err]} {
-		catch {wm withdraw .}
-		error_popup [strcat [mc "Cannot move to top of working directory:"] "\n\n$err"]
-		exit 1
-	}
-	set _gitworktree [pwd]
-	unset cdup
-} elseif {![is_enabled bare]} {
-	if {[is_bare]} {
-		catch {wm withdraw .}
-		error_popup [strcat [mc "Cannot use bare repository:"] "\n\n$_gitdir"]
-		exit 1
-	}
-	if {$_gitworktree eq {}} {
-		set _gitworktree [file dirname $_gitdir]
-	}
-	if {[catch {cd $_gitworktree} err]} {
-		catch {wm withdraw .}
-		error_popup [strcat [mc "No working directory"] " $_gitworktree:\n\n$err"]
-		exit 1
-	}
-	set _gitworktree [pwd]
-}
+# Derive a human-readable repository name
 set _reponame [file split [file normalize $_gitdir]]
 if {[lindex $_reponame end] eq {.git}} {
 	set _reponame [lindex $_reponame end-1]
@@ -1227,9 +1220,6 @@ if {[lindex $_reponame end] eq {.git}} {
 	set _reponame [lindex $_reponame end]
 }
 
-# Export the final paths
-set_gitdir_vars
-
 ######################################################################
 ##
 ## global init
-- 
2.54.0.99.14