git-gui: Fix post-commit status with subject in non-locale encoding

As pointed out in msysgit bug #181, when a non-locale encoding is
used for commits, post-commit status messages display the subject
incorrectly.  It happens because the file handle is not properly
configured before the subject is read back.

This patch fixes it by factoring out the code that is used to setup
the output handle into a separate function, and calling it from
the reading code.

Signed-off-by: Alexander Gavrilov <angavrilov@gmail.com>
Acked-by: Robin Rosenberg <robin.rosenberg@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

lib/commit.tcl

@@ -115,6 +115,23 @@ proc create_new_commit {} {
 	rescan ui_ready
 }
 
+proc setup_commit_encoding {msg_wt {quiet 0}} {
+	global repo_config
+
+	if {[catch {set enc $repo_config(i18n.commitencoding)}]} {
+		set enc utf-8
+	}
+	set use_enc [tcl_encoding $enc]
+	if {$use_enc ne {}} {
+		fconfigure $msg_wt -encoding $use_enc
+	} else {
+		if {!$quiet} {
+			error_popup [mc "warning: Tcl does not support encoding '%s'." $enc]
+		}
+		fconfigure $msg_wt -encoding utf-8
+	}
+}
+
 proc commit_tree {} {
 	global HEAD commit_type file_states ui_comm repo_config
 	global pch_error
@@ -200,16 +217,7 @@ A good commit message has the following format:
 	set msg_p [gitdir GITGUI_EDITMSG]
 	set msg_wt [open $msg_p w]
 	fconfigure $msg_wt -translation lf
-	if {[catch {set enc $repo_config(i18n.commitencoding)}]} {
-		set enc utf-8
-	}
-	set use_enc [tcl_encoding $enc]
-	if {$use_enc ne {}} {
-		fconfigure $msg_wt -encoding $use_enc
-	} else {
-		error_popup [mc "warning: Tcl does not support encoding '%s'." $enc]
-		fconfigure $msg_wt -encoding utf-8
-	}
+	setup_commit_encoding $msg_wt
 	puts $msg_wt $msg
 	close $msg_wt
 
@@ -362,6 +370,7 @@ A rescan will be automatically started now.
 		append reflogm " ($commit_type)"
 	}
 	set msg_fd [open $msg_p r]
+	setup_commit_encoding $msg_fd 1
 	gets $msg_fd subject
 	close $msg_fd
 	append reflogm {: } $subject