From 04add3de60e42d4e8de4138824b89a885ebd667b Mon Sep 17 00:00:00 2001
From: Christian Schmidbauer <christian.schmidbauer@risefx.com>
Date: Fri, 10 Jul 2026 12:22:16 +0200
Subject: [PATCH] fix: report a clear error when config has no [requirements]
 section

mirror() crashed with a bare KeyError when the (hand-written) config
file was missing the [requirements] section. Raise a ValueError with a
message pointing at the config file instead.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 morgan/__init__.py |  3 +++
 tests/test_init.py | 29 +++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/morgan/__init__.py b/morgan/__init__.py
index b1a5144..5835c9b 100644
--- a/morgan/__init__.py
+++ b/morgan/__init__.py
@@ -813,6 +813,9 @@ def mirror(args: argparse.Namespace):
     """
 
     m = Mirrorer(args)
+    if not m.config.has_section("requirements"):
+        msg = f"Config file {args.config} has no [requirements] section"
+        raise ValueError(msg)
     for package in m.config["requirements"]:
         reqs = m.config["requirements"][package].splitlines()
         if not reqs:
diff --git a/tests/test_init.py b/tests/test_init.py
index bcce0df..9c3234c 100644
--- a/tests/test_init.py
+++ b/tests/test_init.py
@@ -12,6 +12,7 @@
 import packaging.version
 import pytest
 
+import morgan
 from morgan import (
     PYPI_ADDRESS,
     Mirrorer,
@@ -761,3 +762,31 @@ def test_process_file_rejects_escaping_path(self, mirrorer, monkeypatch):
         with pytest.raises(ValueError, match="Unsafe file path"):
             # pylint: disable=W0212
             mirrorer._process_file(requirement, fileinfo)  # noqa: SLF001
+
+
+class TestMirrorConfigValidation:
+    def test_mirror_reports_missing_requirements_section(self, tmp_path):
+        config_path = os.path.join(tmp_path, "morgan.ini")
+        with open(config_path, "w", encoding="utf-8") as f:
+            f.write(
+                """
+                [env.test_env]
+                python_version = 3.10
+                sys_platform = linux
+                platform_machine = x86_64
+                """,
+            )
+        args = argparse.Namespace(
+            index_path=str(tmp_path),
+            index_url=PYPI_ADDRESS,
+            config=config_path,
+            mirror_all_versions=False,
+            package_type_regex=r"(whl|zip|tar\.gz)",
+            mirror_all_wheels=False,
+            target_url=None,
+            use_pypi_metadata=False,
+            skip_server_copy=True,
+        )
+
+        with pytest.raises(ValueError, match=r"no \[requirements\] section"):
+            morgan.mirror(args)