console.lua: don't reinsert completion_append after cycling

43ed0a8 avoided reinserting the string that is appended after certain
completions when it is already after the cursor when inserting the
longest common prefix of the suggestions. Do the same when cycling
through them.

player/lua/console.lua

@@ -994,6 +994,13 @@ function max_overlap_length(s1, s2)
     return 0
 end
 
+-- If str starts with the first or last characters of prefix, strip them.
+local function strip_common_characters(str, prefix)
+    return str:sub(1 + math.max(
+        common_prefix_length(prefix, str),
+        max_overlap_length(prefix, str)))
+end
+
 local function cycle_through_suggestions(backwards)
     selected_suggestion_index = selected_suggestion_index + (backwards and -1 or 1)
 
@@ -1005,7 +1012,7 @@ local function cycle_through_suggestions(backwards)
 
     local before_cur = line:sub(1, completion_start_position - 1) ..
                        suggestion_buffer[selected_suggestion_index] .. completion_append
-    line = before_cur .. line:sub(cursor)
+    line = before_cur .. strip_common_characters(line:sub(cursor), completion_append)
     cursor = before_cur:len() + 1
     update()
 end
@@ -1049,15 +1056,10 @@ function complete(backwards)
                 -- If there was only one full match from the list, add
                 -- completer.append to the final string. This is normally a
                 -- space or a quotation mark followed by a space.
-                local after_cur_index = 1
                 completion_append = completer.append or ''
                 if #completions == 1 then
                     prefix = prefix .. completion_append
-
-                    -- calculate offset into after_cur
-                    local prefix_len = common_prefix_length(completion_append, after_cur)
-                    local overlap_size = max_overlap_length(completion_append, after_cur)
-                    after_cur_index = math.max(prefix_len, overlap_size) + 1
+                    after_cur = strip_common_characters(after_cur, completion_append)
                 else
                     table.sort(completions)
                     suggestion_buffer = completions
@@ -1068,7 +1070,7 @@ function complete(backwards)
                 before_cur = before_cur:sub(1, completion_start_position - 1) ..
                              prefix
                 cursor = before_cur:len() + 1
-                line = before_cur .. after_cur:sub(after_cur_index)
+                line = before_cur .. after_cur
                 update()
                 return
             end