Tk Source Code: View Ticket

Ticket UUID:	ab839efc5f783731a882c875cb7aa0a5cb690917
Title:	text edit undo: clearing text instead of restoring
Type:	Bug	Version:	8.6.10 and on
Submitter:	anonymous	Created on:	2024-04-18 03:53:31
Subsystem:	18. [text]	Assigned To:	fvogel
Priority:	5 Medium	Severity:	Important
Status:	Closed	Last Modified:	2024-04-21 11:15:59
Resolution:	Fixed	Closed By:	fvogel
		Closed on:	2024-04-21 11:15:59
Description:	Tk 8.6.10+, Linux and Windows. Run the code snippet below, then select 3rd line using Shift+ArrowUp press Delete key => now 1-2 lines seen only click Undo => now text restored select 3rd line using Shift+ArrowUp press Delete key => now 1-2 lines seen only click Undo => text cleared What??? The text has been cleared instead of restoring it. The worst of all is that after this you cannot restore the original text using undo/redo actions incl. Ctrl+Z and Ctrl+Shift+Z. The issue doesn't appear at: using "event generate" of Undo procedure or using the mouse instead of Shift+ArrowUp keys to select lines The latter is nearly mystical. `puts "Tk v[package require Tk]" #_______________________ proc Undo {} { catch {.txt edit undo} # catch {event generate .txt <<Undo>>} focus .txt } #_______________________ pack [text .txt -height 10 -width 50 -undo 1] pack [ttk::button .but1 -text Undo -command ::Undo] -side left .txt insert 1.0 {1. 123 5 789012 LINE-1 2. 3. 123 5 789012 LINE-3 } focus .txt #_______________________ update`
User Comments:	fvogel added on 2024-04-21 11:15:59: Merged. fvogel added on 2024-04-20 10:14:24: Fixed, with a non-regression test added. See branch bug-ab839efc5f. Will merge soon (to the legacy text widget only). fvogel added on 2024-04-18 20:44:17: Basically, the fix is: Index: generic/tkText.c ================================================================== --- generic/tkText.c +++ generic/tkText.c @@ -5270,15 +5270,17 @@ if (objc != 3) { Tcl_WrongNumArgs(interp, 3, objv, NULL); return TCL_ERROR; } canRedo = TkUndoCanRedo(textPtr->sharedTextPtr->undoStack); + TkUndoInsertUndoSeparator(textPtr->sharedTextPtr->undoStack); if (TextEditUndo(textPtr)) { Tcl_SetObjResult(interp, Tcl_NewStringObj("nothing to undo", -1)); Tcl_SetErrorCode(interp, "TK", "TEXT", "NO_UNDO", NULL); return TCL_ERROR; } + TkUndoInsertUndoSeparator(textPtr->sharedTextPtr->undoStack); canUndo = TkUndoCanUndo(textPtr->sharedTextPtr->undoStack); if (!canRedo \|\| !canUndo) { GenerateUndoStackEvent(textPtr); } break; I believe [1669632] forgot to address this. fvogel added on 2024-04-18 20:03:13: Thanks for the report. I see what's happening and will fix this. Note to myself: this bug does not affect revised_text.