git-gui: fix problem with gui.maxfilesdisplayed

gui.maxfilesdisplayed (added in dd6451f)
was applied brute force on the file list in alphabetic order. As a result,
files that had modifications might not be displayed by git-gui. Even
worse, files that are already in the index might not be displayed, which
makes git-gui hard to use in some workflows.

This fix changes the meaning of gui.maxfilesdisplayed, making it a soft
limit that only applies to "_O" files, i.e. files that are "Untracked,
not staged".

Signed-off-by: Csaba Kiraly <kiraly@disi.unitn.it>
Signed-off-by: Pat Thoyts <patthoyts@users.sourceforge.net>

git-gui.sh

@@ -1965,20 +1965,22 @@ proc display_all_files {} {
 
 	set to_display [lsort [array names file_states]]
 	set display_limit [get_config gui.maxfilesdisplayed]
-	if {[llength $to_display] > $display_limit} {
-		if {!$files_warning} {
-			# do not repeatedly warn:
-			set files_warning 1
-			info_popup [mc "Displaying only %s of %s files." \
-				$display_limit [llength $to_display]]
-		}
-		set to_display [lrange $to_display 0 [expr {$display_limit-1}]]
-	}
+	set displayed 0
 	foreach path $to_display {
 		set s $file_states($path)
 		set m [lindex $s 0]
 		set icon_name [lindex $s 1]
 
+		if {$displayed > $display_limit && [string index $m 1] eq {O} } {
+			if {!$files_warning} {
+				# do not repeatedly warn:
+				set files_warning 1
+				info_popup [mc "Display limit (gui.maxfilesdisplayed = %s) reached, not showing all %s files." \
+					$display_limit [llength $to_display]]
+			}
+			continue
+		}
+
 		set s [string index $m 0]
 		if {$s ne {U} && $s ne {_}} {
 			display_all_files_helper $ui_index $path \
@@ -1993,6 +1995,7 @@ proc display_all_files {} {
 		if {$s ne {_}} {
 			display_all_files_helper $ui_workdir $path \
 				$icon_name $s
+			incr displayed
 		}
 	}