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UIA in conhost: issues with visible ranges #5481
Description
Environment
Windows build number: [run `[Environment]::OSVersion` for powershell, or `ver` for cmd] next (19613.1000).
Windows Terminal version (if applicable): Inbox console
Any other software? NVDA
Steps to reproduce
-
Download this list of domains.
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Start Windows Console and NVDA (with UIA in Windows Console enabled in advanced preferences).
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Run a python interpreter:
python. -
Run:
fin=open("domains.txt")
fin.readlines()
Expected behaviour
Like in pre-21H1 conhost and Windows Terminal 0.11, NVDA reads current output immediately.
Actual behaviour
At this point, NVDA's auto-read lags far behind the actual output in the buffer. Quitting Python with quit() continues reading very old output.
Context
When a text change event is received, NVDA takes a diff of the old and new text and reads only the changed portion of the text. Maybe there's a bug in our diffing algorithm (implemented here, in LiveText._calculateNewText)?
Activity
codeofdusk commentedon Apr 23, 2020
Cc Carlos Zamora (@carlos-zamora).
codeofdusk commentedon Apr 29, 2020
Do you still intend to look at this for 21H1? It would mean a lot for NVDA. Thanks!
codeofdusk commentedon Apr 29, 2020
This bug is not reproducible in Windows Terminal but it is in Conhost.
carlos-zamora commentedon Apr 29, 2020
Bill Dengler (@codeofdusk) Yup! At least for now, we're hoping to get this in for 21H1. Just a bit caught up with stabilizing the last bit of Windows Terminal at the moment, so some of these ConHost bugs are lower priority.
codeofdusk commentedon Jun 5, 2020
Carlos Zamora (@carlos-zamora) Any updates on this one?
carlos-zamora commentedon Jun 5, 2020
Haven't had a chance to look at this one. We're prioritizing some other work right now. I'll be sure to get to this when we start working on ConHost issues though.
codeofdusk commentedon Jul 8, 2020
Do you still plan to get to this for 30 July (21H1)? For context, it's probably the single biggest issue blocking NVDA from using UIA in conhost.
codeofdusk commentedon Aug 16, 2020
Turns out this particular case is due to NVDA's diffing algorithm. Sorry!
codeofdusk commentedon Oct 4, 2020
For future reference, this issue has nothing to do with visible ranges after all! See nvaccess/nvda#11639 for a description of the bug. Thanks Carlos Zamora (@carlos-zamora) for explaining the new behaviour of conhost and helping me track this down!