Add extra logging regarding interpreter discovery (microsoft#21639)

For microsoft#21310

src/client/common/process/rawProcessApis.ts

@@ -100,7 +100,7 @@ export function plainExec(
     const deferred = createDeferred<ExecutionResult<string>>();
     const disposable: IDisposable = {
         dispose: () => {
-            if (!proc.killed && !deferred.completed) {
+            if (!proc.killed) {
                 proc.kill();
             }
         },
@@ -156,10 +156,12 @@ export function plainExec(
             deferred.resolve({ stdout, stderr });
         }
         internalDisposables.forEach((d) => d.dispose());
+        disposable.dispose();
     });
     proc.once('error', (ex) => {
         deferred.reject(ex);
         internalDisposables.forEach((d) => d.dispose());
+        disposable.dispose();
     });
 
     return deferred.promise;

src/client/common/utils/async.ts

@@ -50,11 +50,17 @@ class DeferredImpl<T> implements Deferred<T> {
     }
 
     public resolve(_value: T | PromiseLike<T>) {
+        if (this.completed) {
+            return;
+        }
         this._resolve.apply(this.scope ? this.scope : this, [_value]);
         this._resolved = true;
     }
 
     public reject(_reason?: string | Error | Record<string, unknown>) {
+        if (this.completed) {
+            return;
+        }
         this._reject.apply(this.scope ? this.scope : this, [_reason]);
         this._rejected = true;
     }

src/client/pythonEnvironments/base/locators/lowLevel/activeStateLocator.ts

@@ -20,6 +20,7 @@ export class ActiveStateLocator extends LazyResourceBasedLocator {
             traceVerbose(`Couldn't locate the state binary.`);
             return;
         }
+        traceVerbose(`Searching for active state environments`);
         const projects = await state.getProjects();
         if (projects === undefined) {
             traceVerbose(`Couldn't fetch State Tool projects.`);

src/client/pythonEnvironments/base/locators/lowLevel/microsoftStoreLocator.ts

@@ -87,6 +87,7 @@ export class MicrosoftStoreLocator extends FSWatchingLocator {
 
     protected doIterEnvs(): IPythonEnvsIterator<BasicEnvInfo> {
         const iterator = async function* (kind: PythonEnvKind) {
+            traceVerbose('Searching for windows store envs');
             const exes = await getMicrosoftStorePythonExes();
             yield* exes.map(async (executablePath: string) => ({
                 kind,

src/client/pythonEnvironments/base/locators/lowLevel/posixKnownPathsLocator.ts

@@ -26,6 +26,7 @@ export class PosixKnownPathsLocator extends Locator<BasicEnvInfo> {
         }
 
         const iterator = async function* (kind: PythonEnvKind) {
+            traceVerbose('Searching for interpreters in posix paths locator');
             // Filter out pyenv shims. They are not actual python binaries, they are used to launch
             // the binaries specified in .python-version file in the cwd. We should not be reporting
             // those binaries as environments.

src/client/pythonEnvironments/base/locators/lowLevel/pyenvLocator.ts

@@ -16,6 +16,7 @@ import { traceError, traceVerbose } from '../../../../logging';
  * all the environments (global or virtual) in that directory.
  */
 async function* getPyenvEnvironments(): AsyncIterableIterator<BasicEnvInfo> {
+    traceVerbose('Searching for pyenv environments');
     const pyenvVersionDir = getPyenvVersionsDir();
 
     const subDirs = getSubDirs(pyenvVersionDir, { resolveSymlinks: true });

src/client/pythonEnvironments/base/locators/lowLevel/windowsKnownPathsLocator.ts

@@ -93,6 +93,7 @@ function getDirFilesLocator(
     // rather than in each low-level locator.  In the meantime we
     // take a naive approach.
     async function* iterEnvs(query: PythonLocatorQuery): IPythonEnvsIterator<BasicEnvInfo> {
+        traceVerbose('Searching for windows path interpreters');
         yield* await getEnvs(locator.iterEnvs(query));
         traceVerbose('Finished searching for windows path interpreters');
     }

src/client/pythonEnvironments/base/locators/lowLevel/windowsRegistryLocator.ts

@@ -14,6 +14,7 @@ export class WindowsRegistryLocator extends Locator<BasicEnvInfo> {
     // eslint-disable-next-line class-methods-use-this
     public iterEnvs(): IPythonEnvsIterator<BasicEnvInfo> {
         const iterator = async function* () {
+            traceVerbose('Searching for windows registry interpreters');
             const interpreters = await getRegistryInterpreters();
             for (const interpreter of interpreters) {
                 try {