An error in a regular expression dictionary entry can result in entry deletion rather than giving the user a correction opportunity

[XLTechie]

Steps to reproduce:

1. Open the temporary speech dictionary: NVDA+n, p, d, t.
2. Press Alt+A to add a new entry.
3. Set the pattern as "\(test\)", and the replacement as "\1".
4. Press Alt+E to set as regular expression.
5. Press enter.
6. Press enter.

Note: this is a test string to demonstrate the case. When I encountered this issue, I had entered a very long regexp (about 200 characters), and made some kind of grouping error with one of the groups.

Actual behavior:

NVDA waits until after the dictionary dialog is closed (not the add dialog, the enclosing dictionary dialog). It then:

• Plays an error sound.
• Irrecoverably deletes the added dictionary entry.
• Records something like the following in the log:

ERROR - speechDictHandler.SpeechDict.sub (20:42:36.514) - MainThread (5848):
Invalid dictionary entry 1 in temporary dictionary: "\(test\)", invalid group reference 1 at position 1

Possibly even worse than the addition case I demonstrated here, if you edit an existing entry, and cause a grouping error, the entry is also deleted, rather than, at least, reverting back to its pre-edited state.

Expected behavior:

The dictionary entry is validated when the entry add/edit dialog attempts to close, and if it fails, the user remains in the dialog, and is given a chance to continue work on the entry, without having to re-enter the whole thing as a new entry.

The dictionary already does this for non-grouping errors. For example, try a pattern like: "(\", and a replacement of "test". In that case, when hitting OK to accept the entry, a dialog is shown as follows:

Regular Expression error: "bad escape (end of pattern) at position 1".

Pressing OK in that dialog, returns you to the add/edit dialog, with the existing pattern and replacement still available for further editing.
That is what I would expect for group errors as well.

Furthermore, I'm testing this on alpha, with debug logging. I don't know if a user with disabled logging on a stable branch, would even hear the error beep. If not, then it means the user has no idea this happened.

System configuration

Installed NVDA alpha-20566,dfbda72e, no other versions tested.
Windows 10 Version 2004 (OS Build 19041.388)

Add-ons, reboot, and reg fix tool: N/A

[Adriani90]

cc: @JulienCochuyt

[JulienCochuyt]

Indeed, some errors arise only when using the regex, compiling is not enough.
Adding a substitution attempt after compiling solves at least the simple reported example.
Upcoming PR.