From bd0c1a26c244e3075f538d01c65d195bc0aa6a16 Mon Sep 17 00:00:00 2001
From: Edward Betts <edward@4angle.com>
Date: Mon, 18 May 2026 23:20:40 +0100
Subject: [PATCH] Raise edit API errors with response details

---
 add_links/mediawiki_api.py | 17 +++++++++-----
 test_mediawiki_api.py      | 46 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+), 5 deletions(-)
 create mode 100644 test_mediawiki_api.py

diff --git a/add_links/mediawiki_api.py b/add_links/mediawiki_api.py
index 611ab5b..8319c37 100644
--- a/add_links/mediawiki_api.py
+++ b/add_links/mediawiki_api.py
@@ -1,7 +1,6 @@
 """Interface with the mediawiki API."""
 
 import typing
-from pprint import pprint
 from typing import Any, cast
 
 import requests
@@ -12,6 +11,17 @@ from . import mediawiki_oauth
 class APIError(Exception):
     """Unexpected response from the MediaWiki API."""
 
+
+def _format_api_error(data: dict[str, Any]) -> str:
+    """Format a MediaWiki API error response."""
+    error = data.get("error")
+    if isinstance(error, dict):
+        message = error.get("info") or error.get("code")
+        if message:
+            return str(message)
+    return f"Unexpected MediaWiki API response: {data!r}"
+
+
 wiki_hostname = "en.wikipedia.org"
 wiki_api_php = f"https://{wiki_hostname}/w/api.php"
 user_agent = "add-links/0.1"
@@ -103,8 +113,5 @@ def edit_page(
     }
     ret = call(params, timeout=30)
     if "edit" not in ret:
-        print("params")
-        pprint(params)
-        print()
-        pprint(ret)
+        raise APIError(_format_api_error(ret))
     return typing.cast(str, ret["edit"])
diff --git a/test_mediawiki_api.py b/test_mediawiki_api.py
new file mode 100644
index 0000000..b9fdd34
--- /dev/null
+++ b/test_mediawiki_api.py
@@ -0,0 +1,46 @@
+import unittest
+from unittest.mock import patch
+
+from add_links import mediawiki_api
+
+
+class EditPageTests(unittest.TestCase):
+    def test_edit_page_raises_api_error_with_mediawiki_message(self) -> None:
+        with patch(
+            "add_links.mediawiki_api.call",
+            return_value={"error": {"code": "badtoken", "info": "Invalid CSRF token."}},
+        ):
+            with self.assertRaises(mediawiki_api.APIError) as ctx:
+                mediawiki_api.edit_page(
+                    pageid=1,
+                    section=0,
+                    text="text",
+                    summary="summary",
+                    baserevid="123",
+                    token="bad",
+                )
+
+        self.assertEqual(str(ctx.exception), "Invalid CSRF token.")
+
+    def test_edit_page_raises_api_error_for_unexpected_response(self) -> None:
+        response = {"servedby": "mw-api-ext.eqiad.main"}
+
+        with patch("add_links.mediawiki_api.call", return_value=response):
+            with self.assertRaises(mediawiki_api.APIError) as ctx:
+                mediawiki_api.edit_page(
+                    pageid=1,
+                    section=0,
+                    text="text",
+                    summary="summary",
+                    baserevid="123",
+                    token="token",
+                )
+
+        self.assertEqual(
+            str(ctx.exception),
+            "Unexpected MediaWiki API response: {'servedby': 'mw-api-ext.eqiad.main'}",
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()