fix(plan): forward LOCALAPPDATA so Node's compile cache stays outside the workspace

crates/vite_task_bin/tests/e2e_snapshots/fixtures/node_compile_cache_outside_workspace/a.mjs

@@ -0,0 +1 @@
+export const value = 'a';

crates/vite_task_bin/tests/e2e_snapshots/fixtures/node_compile_cache_outside_workspace/b.mjs

@@ -0,0 +1 @@
+export const value = 'b';

crates/vite_task_bin/tests/e2e_snapshots/fixtures/node_compile_cache_outside_workspace/c.mjs

@@ -0,0 +1 @@
+export const value = 'c';

crates/vite_task_bin/tests/e2e_snapshots/fixtures/node_compile_cache_outside_workspace/package.json

@@ -0,0 +1,5 @@
+{
+  "name": "node-compile-cache-outside-workspace-fixture",
+  "private": true,
+  "type": "module"
+}

crates/vite_task_bin/tests/e2e_snapshots/fixtures/node_compile_cache_outside_workspace/run.mjs

@@ -0,0 +1,20 @@
+// Tiny Node script that turns on the v22 compile cache and imports a
+// few sibling modules so the cache directory actually gets some files
+// written to it. On a normally-configured machine the cache lives in
+// the OS temp directory (outside the workspace), so the runner doesn't
+// see those files when it decides whether the run can be cached.
+//
+// If the spawned process doesn't have LOCALAPPDATA (or TMP/TEMP/
+// USERPROFILE) set on Windows, Node ends up putting the cache inside
+// the workspace, the same files are both written and read in this one
+// run, and the runner refuses to cache it. That's the bug this fixture
+// catches.
+import { enableCompileCache } from 'node:module';
+
+enableCompileCache();
+
+await import('./a.mjs');
+await import('./b.mjs');
+await import('./c.mjs');
+
+console.log('done');

crates/vite_task_bin/tests/e2e_snapshots/fixtures/node_compile_cache_outside_workspace/snapshots.toml

@@ -0,0 +1,20 @@
+[[e2e]]
+name = "node_compile_cache_does_not_poison_workspace"
+comment = """
+Runs a small Node script that turns on Node's compile cache. The cache should land in the OS temp directory (outside the workspace), so two `vt run --cache build` calls should be a miss then a hit. On Windows, if the spawned task env doesn't have `LOCALAPPDATA`, Node puts the cache inside the workspace instead, the runner sees the same files both written and read, and refuses to cache the run — so the second call becomes another miss with a "not cached because it modified its input" message.
+"""
+ignore = true
+steps = [
+  { argv = [
+    "vt",
+    "run",
+    "--cache",
+    "build",
+  ], comment = "first run: cache miss" },
+  { argv = [
+    "vt",
+    "run",
+    "--cache",
+    "build",
+  ], comment = "second run: cache hit" },
+]

crates/vite_task_bin/tests/e2e_snapshots/fixtures/node_compile_cache_outside_workspace/snapshots/node_compile_cache_does_not_poison_workspace.md

@@ -0,0 +1,24 @@
+# node_compile_cache_does_not_poison_workspace
+
+Runs a small Node script that turns on Node's compile cache. The cache should land in the OS temp directory (outside the workspace), so two `vt run --cache build` calls should be a miss then a hit. On Windows, if the spawned task env doesn't have `LOCALAPPDATA`, Node puts the cache inside the workspace instead, the runner sees the same files both written and read, and refuses to cache the run — so the second call becomes another miss with a "not cached because it modified its input" message.
+
+## `vt run --cache build`
+
+first run: cache miss
+
+```
+$ node run.mjs
+done
+```
+
+## `vt run --cache build`
+
+second run: cache hit
+
+```
+$ node run.mjs ◉ cache hit, replaying
+done
+
+---
+vt run: cache hit.
+```

crates/vite_task_bin/tests/e2e_snapshots/fixtures/node_compile_cache_outside_workspace/vite-task.json

@@ -0,0 +1,8 @@
+{
+  "tasks": {
+    "build": {
+      "command": "node run.mjs",
+      "cache": true
+    }
+  }
+}

crates/vite_task_bin/tests/e2e_snapshots/main.rs

@@ -392,6 +392,30 @@ fn run_case(
             // On Windows, ensure common executable extensions are included in PATHEXT for command resolution in subprocesses.
             if cfg!(windows) {
                 cmd.env("PATHEXT", ".COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC");
+                // Forward the Windows env vars Node needs to find a real
+                // temp directory. Without these, Node's compile cache and
+                // similar helpers fall back to a workspace-relative path
+                // and break cached runs. Values come from cargo-test's
+                // own env when present.
+                for name in [
+                    "TMP",
+                    "TEMP",
+                    "APPDATA",
+                    "LOCALAPPDATA",
+                    "PROGRAMDATA",
+                    "USERPROFILE",
+                    "HOMEDRIVE",
+                    "HOMEPATH",
+                    "WINDIR",
+                    "SYSTEMROOT",
+                    "SYSTEMDRIVE",
+                    "ProgramFiles",
+                    "ProgramFiles(x86)",
+                ] {
+                    if let Some(value) = env::var_os(name) {
+                        cmd.env(name, value);
+                    }
+                }
             }
             for (k, v) in step.envs() {
                 let resolved = resolve_env_placeholder(v.as_str());

crates/vite_task_graph/src/config/mod.rs

@@ -445,6 +445,11 @@ pub const DEFAULT_UNTRACKED_ENV: &[&str] = &[
     "RUNNER_*",
     // Windows specific
     "APPDATA",
+    // Node's compile cache uses LOCALAPPDATA to pick its cache directory
+    // on Windows. Without it the cache lands inside the workspace and
+    // breaks every cached task that opts into the compile cache. See
+    // the `node_compile_cache_outside_workspace` e2e fixture.
+    "LOCALAPPDATA",
     "PROGRAMDATA",
     "SYSTEMROOT",
     "SYSTEMDRIVE",