Hi all,

The following NVDA Add-ons community directive applies to ALL add-ons going forward and will be applied when reviewing add-ons:

You can query system environment variables by doing:

import os

os.environ[variableString]

A crucial environment variable is system path (os.environ[“path”]). This variable is used by operating systems (in this case, Windows) to search listed directories for executables. The variable is not really a string – it is a list of strings separated by a semicolon.

If an add-on wants to add new paths to environment variables:

# Don’t do this:

os.environ[“path”] = newStr

# Alternative 1:

Os.environ[“path”] += “;” + pathStr

# Alternative 2:

environPath = os.environ[“path”].split(“;”)

environPath.append(newPath)

os.environ[“path”] = “;”.join(environPath)

# Improved alternative 2:

newPath = somePath

environPath = os.environ[“path”].split(“;”)

if newPath not in environPath:

environPath.append(newPath)

  os.environ[“path”] = “;”.join(environPath)

Any add-on that overrides environment variables without preserving old values will break add-ons that opens executables for their features.

Community directive: going forward, if an add-on is found to have modified system environment variables without preserving existing values will be flagged and authors will be asked to release a fix as soon as possible. Or, for that matter, do NOT ever (EVER) modify environment variables just for convenience (especially system path variable, as it will break NVDA, add-ons, and quite possibly Windows). This directive takes effect immediately.

The above directive applies to all add-ons, including those outside community add-ons website.

Affected add-ons:

• Acapela TTS 1.6.5 (based on investigations by an add-on author).
• Others that directly edit environment path variable without preserving existing values.

Next steps:

1. Existing add-ons on community add-ons website should be examined by authors to see if the above community directive should be applied.
2. New add-ons or add-ons currently under review (including ones with pending review requests) will be subject to the directive before review (including pending review) begins.
3. Developers of add-ons hosted outside community add-ons website will be asked to modify their add-ons if the above community directive should be applied to their add-ons.
4. The NVDA Add-ons community urges developers of Acapela TTS add-on to release a fix as soon as possible.

Cheers,

Joseph