Add support for multi-line secrets in setSecret

packages/core/__tests__/core.test.ts

@@ -164,6 +164,15 @@ describe('@actions/core', () => {
     assertWriteCalls([`::add-mask::secret val${os.EOL}`])
   })
 
+  it('setSecret splits multi line secrets into multiple commands', () => {
+    core.setSecret('first\nsecond\r\nthird')
+    assertWriteCalls([
+      `::add-mask::first${os.EOL}`,
+      `::add-mask::second${os.EOL}`,
+      `::add-mask::third${os.EOL}`
+    ])
+  })
+
   it('prependPath produces the correct commands and sets the env', () => {
     const command = 'PATH'
     createFileCommandFile(command)

packages/core/src/core.ts

@@ -97,7 +97,11 @@ export function exportVariable(name: string, val: any): void {
  * @param secret value of the secret
  */
 export function setSecret(secret: string): void {
-  issueCommand('add-mask', {}, secret)
+  secret.split(/\r?\n|\r/).forEach(part => {
+    if (part) {
+      issueCommand('add-mask', {}, part)
+    }
+  })
 }
 
 /**