filtermail: strip any empty lines at the end (#496)

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## untagged
 
+- filtermail: don't require exactly 2 lines after openPGP payload
+  ([#497](https://github.com/chatmail/chatmail/pull/497))
+
 - cmdeploy dns: offer alternative DKIM record format for some web interfaces
   ([#470](https://github.com/deltachat/chatmail/pull/470))
 

chatmaild/src/chatmaild/filtermail.py

@@ -80,7 +80,9 @@ def check_armored_payload(payload: str):
         return False
     payload = payload.removeprefix(prefix)
 
-    suffix = "-----END PGP MESSAGE-----\r\n\r\n"
+    while payload.endswith("\r\n"):
+        payload = payload.removesuffix("\r\n")
+    suffix = "-----END PGP MESSAGE-----"
     if not payload.endswith(suffix):
         return False
     payload = payload.removesuffix(suffix)

chatmaild/src/chatmaild/tests/test_filtermail.py

@@ -205,10 +205,20 @@ UN4fiB0KR9JyG2ayUdNJVkXZSZLnHyRgiaadlpUo16LVvw==\r
 =b5Kp\r
 -----END PGP MESSAGE-----\r
 \r
+\r
 """
 
     assert check_armored_payload(payload) == True
 
+    payload = payload.removesuffix("\r\n")
+    assert check_armored_payload(payload) == True
+
+    payload = payload.removesuffix("\r\n")
+    assert check_armored_payload(payload) == True
+
+    payload = payload.removesuffix("\r\n")
+    assert check_armored_payload(payload) == True
+
     payload = """-----BEGIN PGP MESSAGE-----\r
 \r
 HELLOWORLD