sapi5: skip over invalid voices rather than causing the entire driver to fail

[michaelDCurran]

Link to issue number:

Fixes #20128

Summary of the issue:

The sapi5 driver can fail completely at initialization, if there is an invalid voice token found in the registry.
Currently NVDA asks sapi5 to enumerate all voices itself using ISpeechVoice::getVoices, however any invalid voice causes the entire enumeration to fail with a COM error.

Description of user facing changes:

• SAPI5 will no longer completely fail if an invalid voice is found on the system. (NVDA 2026.1 can't load sapi 5 64 bit synthesizer #20128)

Description of developer facing changes:

Description of development approach:

• The list of available voice tokens is now generated by manually enumerating the voice keys in the registry, and creating each token from its ID. If one fails to create, it is skipped over.
• Setting the voice now directly converts an ID into a token, rather than re-fetching all tokens and finding which one has the given voiceID.

Testing strategy:

• Locally run both sapi5 64 and sapi5 32 synth drivers in NvDA, moving through voices in the synth settings ring.
• Verify with the issue author that the problem is fixed for their specific case.

Known issues with pull request:

None known.

Code Review Checklist:

• Documentation:
  • Change log entry
  • User Documentation
  • Developer / Technical Documentation
  • Context sensitive help for GUI changes
• Testing:
  • Unit tests
  • System (end to end) tests
  • Manual testing
• UX of all users considered:
  • Speech
  • Braille
  • Low Vision
  • Different web browsers
  • Localization in other languages / culture than English
• API is compatible with existing add-ons.
• Security precautions taken.

[Copilot]

Pull request overview

This PR updates the SAPI5 (64-bit) synth driver initialization so that malformed/invalid voice tokens no longer cause the entire driver to fail. It does this by enumerating voice token IDs directly from the registry and creating tokens one-by-one, skipping those that fail to instantiate.

Changes:

• Add registry-based enumeration of SAPI5 voice token IDs and per-token creation/validation.
• Update _getVoiceTokens to return only successfully created tokens (skipping invalid ones).
• Update voice selection to create a token directly from the stored voice ID, avoiding a full re-enumeration.

[cary-rowen]

Can this be included in the 2026.2?

[michaelDCurran]

Probably not. This needs a lot of testing on alpha.

[seanbudd]

should this target beta since #20128 is on the 2026.2 milestone?

[michaelDCurran]

I have rebased this on beta.