From beb9fd90acdc948e9d8bdd8da89a31c79518c8a0 Mon Sep 17 00:00:00 2001
From: eleanorjboyd <26030610+eleanorjboyd@users.noreply.github.com>
Date: Mon, 2 Mar 2026 21:29:52 -0800
Subject: [PATCH 1/2] feat: pre-warm environment manager caches during
 activation and background refresh

---
 src/extension.ts                          | 14 +++++++++++++-
 src/managers/common/nativePythonFinder.ts |  5 +++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/extension.ts b/src/extension.ts
index 1cd59fb2..070f2cc0 100644
--- a/src/extension.ts
+++ b/src/extension.ts
@@ -10,7 +10,7 @@ import {
     window,
 } from 'vscode';
 import { PythonEnvironment, PythonEnvironmentApi, PythonProjectCreator } from './api';
-import { ENVS_EXTENSION_ID } from './common/constants';
+import { ENVS_EXTENSION_ID, SYSTEM_MANAGER_ID, VENV_MANAGER_ID } from './common/constants';
 import { ensureCorrectVersion } from './common/extVersion';
 import { registerLogger, traceError, traceInfo, traceWarn } from './common/logging';
 import { clearPersistentState, setPersistentState } from './common/persistentState';
@@ -547,6 +547,18 @@ export async function activate(context: ExtensionContext): Promise<PythonEnviron
                 safeRegister('shellStartupVars', shellStartupVarsMgr.initialize()),
             ]);
 
+            // Pre-warm system and venv manager caches before initial environment selection.
+            await Promise.all([
+                envManagers
+                    .getEnvironmentManager(SYSTEM_MANAGER_ID)
+                    ?.getEnvironments('all')
+                    .catch(() => {}),
+                envManagers
+                    .getEnvironmentManager(VENV_MANAGER_ID)
+                    ?.getEnvironments('all')
+                    .catch(() => {}),
+            ]);
+
             await applyInitialEnvironmentSelection(envManagers, projectManager, nativeFinder, api);
 
             // Register manager-agnostic terminal watcher for package-modifying commands
diff --git a/src/managers/common/nativePythonFinder.ts b/src/managers/common/nativePythonFinder.ts
index 33f690e7..eefdedea 100644
--- a/src/managers/common/nativePythonFinder.ts
+++ b/src/managers/common/nativePythonFinder.ts
@@ -238,6 +238,11 @@ class NativePythonFinderImpl implements NativePythonFinder {
             1,
             'NativeRefresh-task',
         );
+
+        // Start discovery immediately so the cache is warm before managers call initialize().
+        void this.refresh(false).catch((err) => {
+            traceWarn('[pet] Background pre-warm refresh failed:', err);
+        });
     }
 
     public async resolve(executable: string): Promise<NativeEnvInfo> {

From bb1377c9d300e154b9d0efdc09eedd1a9edaded0 Mon Sep 17 00:00:00 2001
From: eleanorjboyd <26030610+eleanorjboyd@users.noreply.github.com>
Date: Mon, 2 Mar 2026 21:39:58 -0800
Subject: [PATCH 2/2] updates

---
 src/extension.ts | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/extension.ts b/src/extension.ts
index 070f2cc0..42382c4c 100644
--- a/src/extension.ts
+++ b/src/extension.ts
@@ -549,14 +549,16 @@ export async function activate(context: ExtensionContext): Promise<PythonEnviron
 
             // Pre-warm system and venv manager caches before initial environment selection.
             await Promise.all([
-                envManagers
-                    .getEnvironmentManager(SYSTEM_MANAGER_ID)
-                    ?.getEnvironments('all')
-                    .catch(() => {}),
-                envManagers
-                    .getEnvironmentManager(VENV_MANAGER_ID)
-                    ?.getEnvironments('all')
-                    .catch(() => {}),
+                (
+                    envManagers.getEnvironmentManager(SYSTEM_MANAGER_ID)?.getEnvironments('all') ?? Promise.resolve()
+                ).catch((err) => {
+                    traceWarn('[pre-warm] System manager cache warm-up failed:', err);
+                }),
+                (envManagers.getEnvironmentManager(VENV_MANAGER_ID)?.getEnvironments('all') ?? Promise.resolve()).catch(
+                    (err) => {
+                        traceWarn('[pre-warm] Venv manager cache warm-up failed:', err);
+                    },
+                ),
             ]);
 
             await applyInitialEnvironmentSelection(envManagers, projectManager, nativeFinder, api);