gitk: Synchronize config file writes

diff --git a/gitk b/gitk
index 26a7db4c8c27415738ce9ced7754563cf3f2d28c..0325ab0ca2b60876db2b5fc3209e3fdcc77fe5a0 100755 (executable)
--- a/gitk
+++ b/gitk
@@ -2783,6 +2783,21 @@ proc doprogupdate {} {
     }
 }
 
+proc config_check_tmp_exists {tries_left} {
+    global config_file_tmp
+
+    if {[file exists $config_file_tmp]} {
+       incr tries_left -1
+       if {$tries_left > 0} {
+           after 100 [list config_check_tmp_exists $tries_left]
+       } else {
+           error_popup "There appears to be a stale $config_file_tmp\
+ file, which will prevent gitk from saving its configuration on exit.\
+ Please remove it if it is not being used by any existing gitk process."
+       }
+    }
+}
+
 proc config_init_trace {name} {
     global config_variable_changed config_variable_original
 
@@ -2818,11 +2833,16 @@ proc savestuff {w} {
 
     if {$stuffsaved} return
     if {![winfo viewable .]} return
+    set remove_tmp 0
     if {[catch {
-       if {[file exists $config_file_tmp]} {
-           file delete -force $config_file_tmp
+       set try_count 0
+       while {[catch {set f [open $config_file_tmp {WRONLY CREAT EXCL}]}]} {
+           if {[incr try_count] > 50} {
+               error "Unable to write config file: $config_file_tmp exists"
+           }
+           after 100
        }
-       set f [open $config_file_tmp w]
+       set remove_tmp 1
        if {$::tcl_platform(platform) eq {windows}} {
            file attributes $config_file_tmp -hidden true
        }
@@ -2884,9 +2904,13 @@ proc savestuff {w} {
        puts $f "}"
        close $f
        file rename -force $config_file_tmp $config_file
+       set remove_tmp 0
     } err]} {
         puts "Error saving config: $err"
     }
+    if {$remove_tmp} {
+       file delete -force $config_file_tmp
+    }
     set stuffsaved 1
 }
 
@@ -12177,6 +12201,7 @@ catch {
     }
     source $config_file
 }
+config_check_tmp_exists 50
 
 set config_variables {
     mainfont textfont uifont tabstop findmergefiles maxgraphpct maxwidth