msvc-dev-cmv v1.8.1

Also updating and adding whatever the new version of npm wants to be
updated and added in its package files. This should not affect the
behavior of the action.

.github/workflows/main.yml

@@ -18,6 +18,8 @@ jobs:
         uses: actions/checkout@v2
       - name: Download Internet
         run: npm install
+      - name: Run eslint
+        run: npm run lint
       - name: Enable Developer Command Prompt (amd64)
         uses: ./
         with:

index.js

@@ -116,25 +116,27 @@ function main() {
     const vcvars = `"${findVcvarsall()}" ${args.join(' ')}`
     core.debug(`vcvars command-line: ${vcvars}`)
 
-    const old_environment = child_process.execSync(`set`, {shell: "cmd"}).toString().split('\r\n')
-    const new_environment = child_process.execSync(`${vcvars} && set`, {shell: "cmd"}).toString().split('\r\n')
+    const cmd_output_string = child_process.execSync(`set && cls && ${vcvars} && cls && set`, {shell: "cmd"}).toString()
+    const cmd_output_parts = cmd_output_string.split('\f')
+
+    const old_environment = cmd_output_parts[0].split('\r\n')
+    const vcvars_output   = cmd_output_parts[1].split('\r\n')
+    const new_environment = cmd_output_parts[2].split('\r\n')
 
     // If vsvars.bat is given an incorrect command line, it will print out
     // an error and *still* exit successfully. Parse out errors from output
     // which don't look like environment variables, and fail if appropriate.
-    var failed = false
-    for (let line of new_environment) {
+    const error_messages = vcvars_output.filter((line) => {
         if (line.match(/^\[ERROR.*\]/)) {
-            failed = true
             // Don't print this particular line which will be confusing in output.
-            if (line.match(/Error in script usage. The correct usage is:$/)) {
-                continue
+            if (!line.match(/Error in script usage. The correct usage is:$/)) {
+                return true
             }
-            core.error(line)
         }
-    }
-    if (failed) {
-        throw new Error('invalid parameters')
+        return false
+    })
+    if (error_messages.length > 0) {
+        throw new Error('invalid parameters' + '\r\n' + error_messages.join('\r\n'))
     }
 
     // Convert old environment lines into a dictionary for easier lookup.