Always attempt MSVC environment setup on Windows

GraalVM native-image (released versions ≤21.0.x) uses a `20\d\d` regex
to find Visual Studio installations, which does not match VS 2026's
`\18\` directory. Previously, the action skipped MSVC setup for JDK 17+
assuming native-image handles it — but it can't find VS 2026.

Now the action always runs vcvarsall.bat on Windows, putting cl.exe on
PATH so native-image skips its own detection. For JDK 17+ and dev
builds, failures are non-fatal (warning instead of error) since future
native-image versions with vswhere support will handle it.

Fixes #220

Author: gastaldi

dist/main.js

@@ -44,42 +44,49 @@ export function setUpWindowsEnvironment(
   graalVMVersion: string,
   isGraalVMforJDK17OrLater: boolean
 ): void {
-  if (!needsWindowsEnvironmentSetup(javaVersion, graalVMVersion, isGraalVMforJDK17OrLater)) {
-    return
-  }
+  const isRequired = needsWindowsEnvironmentSetup(javaVersion, graalVMVersion, isGraalVMforJDK17OrLater)
 
   core.startGroup('Updating Windows environment...')
 
-  const vcvarsallPath = findVcvarsallPath()
-  core.debug(`Calling "${vcvarsallPath}"...`)
-  const [originalEnv, vcvarsallOutput, updatedEnv] = execSync(`set && cls && "${vcvarsallPath}" x64 && cls && set`, {
-    shell: 'cmd'
-  })
-    .toString()
-    .split('\f') // form feed page break (printed by `cls`)
-  core.debug(vcvarsallOutput)
+  try {
+    const vcvarsallPath = findVcvarsallPath()
+    core.debug(`Calling "${vcvarsallPath}"...`)
+    const [originalEnv, vcvarsallOutput, updatedEnv] = execSync(`set && cls && "${vcvarsallPath}" x64 && cls && set`, {
+      shell: 'cmd'
+    })
+      .toString()
+      .split('\f') // form feed page break (printed by `cls`)
+    core.debug(vcvarsallOutput)
 
-  const originalEnvMap = new Map<string, string>()
-  for (const line of originalEnv.split('\r\n')) {
-    if (line.includes('=')) {
-      const [name, value] = line.split('=')
-      originalEnvMap.set(name, value)
-    } else if (line) {
-      core.debug(`Skipping ${line} (does not include '=')...`)
+    const originalEnvMap = new Map<string, string>()
+    for (const line of originalEnv.split('\r\n')) {
+      if (line.includes('=')) {
+        const [name, value] = line.split('=')
+        originalEnvMap.set(name, value)
+      } else if (line) {
+        core.debug(`Skipping ${line} (does not include '=')...`)
+      }
     }
-  }
 
-  for (const line of updatedEnv.split('\r\n')) {
-    if (line.includes('=')) {
-      const [name, value] = line.split('=')
-      const originalValue = originalEnvMap.get(name)
-      if (value !== originalValue) {
-        core.exportVariable(name, value)
-        core.debug(`"${name}" set to "${value}"`)
+    for (const line of updatedEnv.split('\r\n')) {
+      if (line.includes('=')) {
+        const [name, value] = line.split('=')
+        const originalValue = originalEnvMap.get(name)
+        if (value !== originalValue) {
+          core.exportVariable(name, value)
+          core.debug(`"${name}" set to "${value}"`)
+        }
+      } else if (line) {
+        core.debug(`Skipping ${line} (does not include '=')...`)
       }
-    } else if (line) {
-      core.debug(`Skipping ${line} (does not include '=')...`)
     }
+  } catch (error) {
+    if (isRequired) {
+      throw error
+    }
+    core.warning(
+      `${error instanceof Error ? error.message : error}. This is not required for this version of GraalVM but native-image may fail if Visual Studio cannot be detected automatically.`
+    )
   }
 
   core.endGroup()