Do not fail interpreter discovery if accessing Windows registry fails.

[karrtikr]

For #12962

• Pull request represents a single change (i.e. not fixing disparate/unrelated things in a single PR).
• Title summarizes what is changing.
• Has a news entry file (remember to thank yourself!).
• Appropriate comments and documentation strings in the code.
• Has sufficient logging.
• Has telemetry for enhancements.
• Unit tests & system/integration tests are added/updated.
• Test plan is updated as appropriate.
• package-lock.json has been regenerated by running npm install (if dependencies have changed).
• The wiki is updated with any design decisions/details.

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities (and 0 Security Hotspots to review)
0 Code Smells

No Coverage information
1.0% Duplication

[codecov-commenter]

Codecov Report

Merging #13369 into master will decrease coverage by 0.06%.
The diff coverage is 16.66%.

@@ Coverage Diff @@ ## master #13369 +/- ## ========================================== - Coverage 59.75% 59.68% -0.07%  ========================================== Files 670 670 Lines 37303 37347 +44 Branches 5296 5306 +10 ========================================== + Hits 22290 22291 +1  - Misses 13878 13919 +41  - Partials 1135 1137 +2 

Impacted Files	Coverage Δ
src/client/common/platform/registry.ts	27.65% <12.50%> (-1.61%)	⬇️
...covery/locators/services/windowsRegistryService.ts	89.47% <25.00%> (-1.84%)	⬇️
src/client/common/utils/platform.ts	64.70% <0.00%> (-11.77%)	⬇️
src/client/datascience/crossProcessLock.ts	79.41% <0.00%> (-11.77%)	⬇️
...ient/datascience/editor-integration/codewatcher.ts	68.03% <0.00%> (-2.59%)	⬇️
src/client/linters/pydocstyle.ts	86.66% <0.00%> (-2.23%)	⬇️
src/client/datascience/debugLocationTracker.ts	76.56% <0.00%> (-1.57%)	⬇️
src/client/common/process/proc.ts	14.49% <0.00%> (-0.73%)	⬇️
src/datascience-ui/common/index.ts	95.72% <0.00%> (-0.15%)	⬇️
src/client/datascience/commands/commandRegistry.ts	34.50% <0.00%> (-0.03%)	⬇️
... and 4 more

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[karthiknadig]

Look at the getRegistryKeys implementation. We already return empty array. I don't think we will hit this case.

vscode-python/src/client/common/platform/registry.ts

Line 52 in 61b179b

return resolve([]);

[karrtikr]

vscode-python/src/client/common/platform/registry.ts

Lines 54 to 66 in 776a5ad

	async function getRegistryKeys(options: Options): Promise<string[]> {
	// tslint:disable-next-line:no-require-imports
	const Registry = require('winreg') as typeof import('winreg');
	// https://github.com/python/peps/blob/master/pep-0514.txt#L85
	return new Promise<string[]>((resolve) => {
	new Registry(options).keys((error, result) => {
	if (error || !Array.isArray(result)) {
	return resolve([]);
	}
	resolve(result.filter((item) => typeof item.key === 'string').map((item) => item.key));
	});
	});
	}

I think you're assuming that new Registry(options).keys at line 59 does not throw any errors and respects the callback. I checked the error trace user uploaded,

console.ts:137 [Extension Host] Error Python Extension: 2020-07-15 14:50:32: Get Interpreters, Class name = m, completed in 9ms, has a falsy return value, Arg 1: <Uri:c:\Users\chmay\source\mkl\mkl_email_service>, Arg 2: {"onSuggestion":true}, Return Value: undefined Error: spawn EPERM at ChildProcess.spawn (internal/child_process.js:394:11) at spawn (child_process.js:553:9) at y.keys (c:\Users\chmay\.vscode\extensions\ms-python.python-2020.6.91350\out\client\extension.js:1:621980) at c:\Users\chmay\.vscode\extensions\ms-python.python-2020.6.91350\out\client\extension.js:1:617508 at new Promise (<anonymous>) at c:\Users\chmay\.vscode\extensions\ms-python.python-2020.6.91350\out\client\extension.js:1:617483 at c.getKeys (c:\Users\chmay\.vscode\extensions\ms-python.python-2020.6.91350\out\client\extension.js:1:617615) at b.getCompanies (c:\Users\chmay\.vscode\extensions\ms-python.python-2020.6.91350\out\client\extension.js:48:796340) at b.getInterpretersFromRegistry (c:\Users\chmay\.vscode\extensions\ms-python.python-2020.6.91350\out\client\extension.js:48:795831) 

It fails at y.keys in the extension code, which is new Registry(options).keys

[karthiknadig]

I see. Go it.

[karthiknadig]

Same as above.

[karrtikr]

I have put this just to make sure we fix the bug. We should probably have done this with all locators.

[ericsnowcurrently]

LGTM

This feels more like a bandaid than a full fix, but I understand the constraints here.