fix(env): Do not clobber defined 'env' script

If an env script is already defined, run that
instead of the default.

PR-URL: #2655
Credit: @isaacs
Close: #2655
Reviewed-by: @ljharb

lib/run-script.js

@@ -41,7 +41,7 @@ const runScript = async (args) => {
 
   if (event === 'restart' && !scripts.restart)
     scripts.restart = 'npm stop --if-present && npm start'
-  else if (event === 'env')
+  else if (event === 'env' && !scripts.env)
     scripts.env = isWindowsShell ? 'SET' : 'env'
 
   pkg.scripts = scripts

package.json

@@ -45,7 +45,6 @@
     "@npmcli/arborist": "^2.2.1",
     "@npmcli/ci-detect": "^1.2.0",
     "@npmcli/config": "^1.2.9",
-    "@npmcli/installed-package-contents": "^1.0.7",
     "@npmcli/run-script": "^1.8.2",
     "abbrev": "~1.1.1",
     "ansicolors": "~0.3.2",

test/lib/run-script.js

@@ -126,12 +126,14 @@ t.test('default env, start, and restart scripts', async t => {
         scriptShell: undefined,
         stdio: 'inherit',
         stdioString: true,
-        pkg: { name: 'x',
+        pkg: {
+          name: 'x',
           version: '1.2.3',
           _id: '[email protected]',
           scripts: {
             env: 'env',
-          } },
+          },
+        },
         event: 'env',
       },
     ])
@@ -185,6 +187,67 @@ t.test('default env, start, and restart scripts', async t => {
   RUN_SCRIPTS.length = 0
 })
 
+t.test('non-default env script', async t => {
+  npm.localPrefix = t.testdir({
+    'package.json': JSON.stringify({
+      name: 'x',
+      version: '1.2.3',
+      scripts: {
+        env: 'hello',
+      },
+    }),
+  })
+
+  await runScript(['env'], er => {
+    if (er)
+      throw er
+
+    t.match(RUN_SCRIPTS, [
+      {
+        path: npm.localPrefix,
+        args: [],
+        scriptShell: undefined,
+        stdio: 'inherit',
+        stdioString: true,
+        pkg: {
+          name: 'x',
+          version: '1.2.3',
+          _id: '[email protected]',
+          scripts: {
+            env: 'hello',
+          },
+        },
+        event: 'env',
+      },
+    ])
+  })
+  RUN_SCRIPTS.length = 0
+
+  await runScriptWin(['env'], er => {
+    if (er)
+      throw er
+
+    t.match(RUN_SCRIPTS, [
+      {
+        path: npm.localPrefix,
+        args: [],
+        scriptShell: undefined,
+        stdio: 'inherit',
+        stdioString: true,
+        pkg: { name: 'x',
+          version: '1.2.3',
+          _id: '[email protected]',
+          scripts: {
+            env: 'hello',
+          },
+        },
+        event: 'env',
+      },
+    ])
+  })
+  RUN_SCRIPTS.length = 0
+})
+
 t.test('try to run missing script', t => {
   npm.localPrefix = t.testdir({
     'package.json': JSON.stringify({