fix(github-http): return None on malformed GHES port instead of raising

src/specify_cli/_github_http.py

@@ -127,7 +127,14 @@ def _is_asset_path(segments: list[str]) -> bool:
     if hostname == "github.com":
         api_base = "https://api.github.com"
     elif is_ghes:
-        authority = hostname if parsed.port is None else f"{hostname}:{parsed.port}"
+        # ``parsed.port`` raises ValueError on a malformed port (e.g.
+        # ``host:notaport``); the function's contract is to return None for
+        # anything it can't resolve, not to raise.
+        try:
+            port = parsed.port
+        except ValueError:
+            return None
+        authority = hostname if port is None else f"{hostname}:{port}"
         api_base = f"{parsed.scheme}://{authority}/api/v3"
     else:
         return None

tests/test_github_http.py

@@ -233,6 +233,23 @@ def recording_open(url, timeout=None, extra_headers=None):
         assert result is None
         assert called == []
 
+    def test_returns_none_on_malformed_ghes_port(self):
+        """A malformed port on an allowlisted GHES host returns None, not a
+        ValueError (contract: resolve or return None, never raise)."""
+        called = []
+
+        def open_never(url, timeout=None, extra_headers=None):
+            called.append(url)
+            raise AssertionError("open_url_fn must not be called")
+
+        result = resolve_github_release_asset_api_url(
+            "https://ghes.example:notaport/o/r/releases/download/v1/ext.zip",
+            open_never,
+            github_hosts=("ghes.example",),
+        )
+        assert result is None
+        assert called == []
+
     def test_passthrough_for_unlisted_ghes_api_asset_url(self):
         """A direct GHES /api/v3 asset URL passes through even when the host is
         not allowlisted: passthrough issues no API request, and the download