fix: catch some StopIteration exceptions

src/ahriman/core/alpm/pacman_database.py

@@ -138,8 +138,14 @@ class PacmanDatabase(SyncHttpClient):
 
         Args:
             force(bool): force database synchronization (same as ``pacman -Syy``)
+
+        Raises:
+            PacmanError: on operation error (invalid scheme or incomplete configuration)
         """
-        server = next(iter(self.database.servers))
+        try:
+            server = next(iter(self.database.servers))
+        except StopIteration:
+            raise PacmanError("No configured servers available for database") from None
         filename = f"{self.database.name}.files.tar.gz"
         url = f"{server}/{filename}"
 

src/ahriman/core/exceptions.py

@@ -116,6 +116,19 @@ class GitRemoteError(RuntimeError):
         RuntimeError.__init__(self, "Git remote failed")
 
 
+class GPGError(RuntimeError):
+    """
+    PGP/GPG related exception
+    """
+
+    def __init__(self, details: str) -> None:
+        """
+        Args:
+            details(str): details of the exception
+        """
+        RuntimeError.__init__(self, f"GPG operation failed: {details}")
+
+
 class InitializeError(RuntimeError):
     """
     base service initialization exception

src/ahriman/core/sign/gpg.py

@@ -20,7 +20,7 @@
 from pathlib import Path
 
 from ahriman.core.configuration import Configuration
-from ahriman.core.exceptions import BuildError
+from ahriman.core.exceptions import BuildError, GPGError
 from ahriman.core.http import SyncHttpClient
 from ahriman.core.utils import check_output
 from ahriman.models.sign_settings import SignSettings
@@ -147,12 +147,19 @@ class GPG(SyncHttpClient):
 
         Returns:
             str: full PGP key fingerprint
+
+        Raises:
+            GPGError: if key is in wrong format
         """
-        metadata = check_output("gpg", "--with-colons", "--fingerprint", key, logger=self.logger)
         # fingerprint line will be like
         # fpr:::::::::43A663569A07EE1E4ECC55CC7E3A4240CE3C45C2:
-        fingerprint = next(filter(lambda line: line[:3] == "fpr", metadata.splitlines()))
-        return fingerprint.split(":")[-2]
+        metadata = check_output("gpg", "--with-colons", "--fingerprint", key, logger=self.logger)
+
+        try:
+            fingerprint = next(filter(lambda line: line[:3] == "fpr", metadata.splitlines()))
+            return fingerprint.split(":")[-2]
+        except (IndexError, StopIteration):
+            raise GPGError(f"key {key} has invalid metadata") from None
 
     def key_import(self, server: str, key: str) -> None:
         """

src/ahriman/models/user.py

@@ -88,8 +88,12 @@ class User:
         """
         if not self.password:
             return None
-        algo = next(segment for segment in self.password.split("$") if segment)
-        return f"${algo}$"
+
+        try:
+            algo = next(segment for segment in self.password.split("$") if segment)
+            return f"${algo}$"
+        except StopIteration:
+            return None
 
     @staticmethod
     def generate_password(length: int) -> str: