Add more entry and package cache guards to env modules.

src/env/has-loader-value.js

@@ -2,6 +2,7 @@ import { extname, sep } from "../safe/path.js"
 
 import CHAR_CODE from "../constant/char-code.js"
 
+import Loader from "../loader.js"
 import Module from "../module.js"
 
 import esmResolveFilename from "../module/esm/resolve-filename.js"
@@ -48,15 +49,38 @@ function init() {
   }
 
   function tryResolveFilename(request, parent, isMain) {
-    try {
-      return esmResolveFilename(request, parent, isMain)
-    } catch {}
+    const entryState = shared.entry
+    const entryCache = entryState.cache
+
+    const pkgState = Loader.state.package
+    const pkgCache = pkgState.cache
+
+    entryState.cache = new WeakMap
+    pkgState.cache = new Map
+
+    let result
+    let threw = true
 
     try {
-      return Module._resolveFilename(request, parent, isMain)
+      result = esmResolveFilename(request, parent, isMain)
+      threw = false
     } catch {}
 
-    return ""
+    if (threw) {
+      try {
+        result = Module._resolveFilename(request, parent, isMain)
+        threw = false
+      } catch {}
+    }
+
+    entryState.cache = entryCache
+    pkgState.cache = pkgCache
+
+    if (threw) {
+      return ""
+    }
+
+    return result
   }
 
   return hasLoaderValue

src/env/is-sideloaded.js

@@ -17,12 +17,16 @@ function init() {
 
     const args = argv.slice(2)
 
-    let filename
-    let nodeModulesIndex = -1
+    if (args.length === 0) {
+      return false
+    }
+
+    const filename = realpath(argv[1])
+    const nodeModulesIndex = normalize(filename).lastIndexOf("/node_modules/")
 
-    if (args.length) {
-      filename = realpath(argv[1])
-      nodeModulesIndex = normalize(filename).lastIndexOf("/node_modules/")
+    if (nodeModulesIndex === -1 ||
+        ! hasLoaderArg(args)) {
+      return false
     }
 
     const entryState = shared.entry
@@ -36,11 +40,8 @@ function init() {
 
     let result = false
 
-    // From a package like Mocha.
-    if (nodeModulesIndex !== -1 &&
-        hasLoaderArg(args) &&
-        (Package.get(cwd()) !== null ||
-         Package.get(filename.slice(0, nodeModulesIndex + 1)) !== null)) {
+    if (Package.get(cwd()) !== null ||
+        Package.get(filename.slice(0, nodeModulesIndex + 1)) !== null) {
       result = true
     }