chore(test): add #[serial] to env-var tests to prevent concurrent access races

CLAUDE.md

@@ -106,6 +106,12 @@ All user-facing output must go through shared output modules instead of raw prin
 - Run `cargo test` to execute all tests
 - You never need to run `pnpm install` in the test fixtures dir, vite-plus should able to load and parse the workspace without `pnpm install`.
 
+### Environment Variables in Tests
+
+- **Prefer `EnvConfig::test_scope()`**: For tests needing custom config values (VP_HOME, npm registry, etc.), use thread-local `EnvConfig::test_scope()` or `EnvConfig::test_guard()` from `vite_shared` — no `unsafe`, no `#[serial]`, full parallelism
+- **`#[serial]` required for `std::env::set_var`/`remove_var`**: Any test that directly modifies process env vars (PATH, VP_SHIM_TOOL, etc.) MUST have `#[serial_test::serial]` to prevent concurrent access races
+- **Clean up ALL related env vars**: When clearing env vars before a test, clear ALL vars that the function under test reads — not just the one being tested
+
 ## Build
 
 - Run `pnpm bootstrap-cli` from the project root to build all packages and install the global CLI

crates/vite_global_cli/src/shim/mod.rs

@@ -217,10 +217,18 @@ mod tests {
         assert!(!is_potential_package_binary("another-fake-tool"));
     }
 
+    /// Clear both shim env vars to isolate tests.
+    /// SAFETY: caller must be `#[serial]` since this mutates process-global state.
+    unsafe fn clear_shim_env_vars() {
+        unsafe {
+            std::env::remove_var(SHIM_TOOL_ENV_VAR);
+            std::env::remove_var(LEGACY_SHIM_TOOL_ENV_VAR);
+        }
+    }
+
     #[test]
     #[serial]
     fn test_detect_shim_tool_from_env_var() {
-        // SAFETY: We're in a test at startup, no other threads
         unsafe {
             std::env::set_var(SHIM_TOOL_ENV_VAR, "node");
             std::env::remove_var(LEGACY_SHIM_TOOL_ENV_VAR);
@@ -236,7 +244,6 @@ mod tests {
     fn test_detect_shim_tool_from_legacy_env_var() {
         // When only VITE_PLUS_SHIM_TOOL is set (older trampoline), it should
         // fall back to reading the legacy env var.
-        // SAFETY: We're in a test at startup, no other threads
         unsafe {
             std::env::remove_var(SHIM_TOOL_ENV_VAR);
             std::env::set_var(LEGACY_SHIM_TOOL_ENV_VAR, "npm");
@@ -247,43 +254,28 @@ mod tests {
         assert!(std::env::var(LEGACY_SHIM_TOOL_ENV_VAR).is_err());
     }
 
+    /// Tests that argv0-based tool detection works for a given tool name,
+    /// including full path and .exe extension variants.
+    fn assert_detect_shim_tool_from_argv0(tool: &str) {
+        unsafe { clear_shim_env_vars() };
+
+        assert_eq!(detect_shim_tool(tool), Some(tool.to_string()));
+        assert_eq!(
+            detect_shim_tool(&vite_str::format!("/home/user/.vite-plus/bin/{tool}")),
+            Some(tool.to_string()),
+        );
+        assert_eq!(detect_shim_tool(&vite_str::format!("{tool}.exe")), Some(tool.to_string()),);
+    }
+
     #[test]
     #[serial]
     fn test_detect_shim_tool_vpx() {
-        // vpx should be detected via the argv0 check, before the env var check
-        // and before is_shim_tool (which would incorrectly match it as a package binary)
-        // SAFETY: We're in a test
-        unsafe {
-            std::env::remove_var(SHIM_TOOL_ENV_VAR);
-        }
-        let result = detect_shim_tool("vpx");
-        assert_eq!(result, Some("vpx".to_string()));
-
-        // Also works with full path
-        let result = detect_shim_tool("/home/user/.vite-plus/bin/vpx");
-        assert_eq!(result, Some("vpx".to_string()));
-
-        // Also works with .exe extension (Windows)
-        let result = detect_shim_tool("vpx.exe");
-        assert_eq!(result, Some("vpx".to_string()));
+        assert_detect_shim_tool_from_argv0("vpx");
     }
 
     #[test]
+    #[serial]
     fn test_detect_shim_tool_vpr() {
-        // vpr should be detected via the argv0 check, same pattern as vpx
-        // SAFETY: We're in a test
-        unsafe {
-            std::env::remove_var(SHIM_TOOL_ENV_VAR);
-        }
-        let result = detect_shim_tool("vpr");
-        assert_eq!(result, Some("vpr".to_string()));
-
-        // Also works with full path
-        let result = detect_shim_tool("/home/user/.vite-plus/bin/vpr");
-        assert_eq!(result, Some("vpr".to_string()));
-
-        // Also works with .exe extension (Windows)
-        let result = detect_shim_tool("vpr.exe");
-        assert_eq!(result, Some("vpr".to_string()));
+        assert_detect_shim_tool_from_argv0("vpr");
     }
 }

crates/vite_shared/Cargo.toml

@@ -22,5 +22,8 @@ which = { workspace = true }
 [target.'cfg(not(target_os = "windows"))'.dependencies]
 rustls = { workspace = true }
 
+[dev-dependencies]
+serial_test = { workspace = true }
+
 [lints]
 workspace = true

crates/vite_shared/src/home.rs

@@ -64,6 +64,7 @@ mod tests {
     }
 
     #[test]
+    #[serial_test::serial]
     fn test_get_vite_plus_without_home() {
         use std::path::PathBuf;
 

crates/vite_shared/src/path_env.rs

@@ -142,7 +142,7 @@ mod tests {
     }
 
     #[test]
-    #[ignore]
+    #[serial_test::serial]
     fn test_format_path_prepended_always_prepends() {
         // Even if the directory exists somewhere in PATH, it should be prepended
         let test_dir = "/test/node/bin";