Support https://launchpad.net/bugs/<number> as a valid Launchpad bug URL

backend/test_observer/controllers/issues/issue_url_parser.py

@@ -14,12 +14,41 @@
 # SPDX-License-Identifier: AGPL-3.0-only
 
 import re
+from urllib.parse import urlparse
 
+import requests
 from pydantic import HttpUrl
 
 from test_observer.data_access.models_enums import IssueSource
 
 
+def _resolve_launchpad_short_url(bug_id: str) -> tuple[str, str]:
+    """
+    Resolve a short Launchpad bug URL (launchpad.net/bugs/<id>) by following
+    its redirect and extracting the project and key from the canonical URL.
+
+    Returns:
+        (project, key) extracted from the redirect target.
+    Raises:
+        ValueError if the redirect cannot be followed or parsed.
+    """
+    short_url = f"https://launchpad.net/bugs/{bug_id}"
+    try:
+        response = requests.head(short_url, allow_redirects=True, timeout=10)
+        resolved_url = response.url
+    except requests.RequestException as e:
+        raise ValueError(f"Could not resolve Launchpad short URL {short_url}: {e}") from e
+
+    parsed = urlparse(resolved_url)
+    match = re.match(r"^/([^/]+)(?:/\+source/[^/]+)?/\+bug/(\d+)$", parsed.path)
+    if match and parsed.hostname == "bugs.launchpad.net":
+        return match.group(1).lower(), match.group(2)
+
+    raise ValueError(
+        f"Launchpad short URL {short_url} resolved to an unrecognised URL: {resolved_url}"
+    )
+
+
 def issue_source_project_key_from_url(url: HttpUrl) -> tuple[IssueSource, str, str]:
     """
     Extract (source, project, key) from an issue URL.
@@ -44,12 +73,19 @@ def issue_source_project_key_from_url(url: HttpUrl) -> tuple[IssueSource, str, s
         if match:
             return IssueSource.LAUNCHPAD, match.group(1).lower(), match.group(2)
 
+    elif host == "launchpad.net":
+        match = re.match(r"^/bugs/(\d+)$", path)
+        if match:
+            project, key = _resolve_launchpad_short_url(match.group(1))
+            return IssueSource.LAUNCHPAD, project, key
+
     raise ValueError(
         f"Unrecognized issue URL format:\n"
         f"  host = '{host}'\n"
         f"  path = '{path}'\n\n"
         f"Expected formats:\n"
         f"  GitHub:     https://github.com/<owner>/<repo>/issues/<number>\n"
         f"  JIRA:       https://warthogs.atlassian.net/browse/<PROJECT-123>\n"
-        f"  Launchpad:  https://bugs.launchpad.net/<project>/+bug/<number>"
+        f"  Launchpad:  https://bugs.launchpad.net/<project>/+bug/<number>\n"
+        f"  Launchpad:  https://launchpad.net/bugs/<number>"
     )

backend/test_observer/data_access/models.py

@@ -879,7 +879,9 @@ def url(self) -> str:
         elif self.source == IssueSource.JIRA:
             return f"https://warthogs.atlassian.net/browse/{self.project}-{self.key}"
         elif self.source == IssueSource.LAUNCHPAD:
-            return f"https://bugs.launchpad.net/{self.project}/+bug/{self.key}"
+            if self.project:
+                return f"https://bugs.launchpad.net/{self.project}/+bug/{self.key}"
+            return f"https://launchpad.net/bugs/{self.key}"
         raise ValueError("Unrecognized issue source")
 
     @url.inplace.expression
@@ -906,11 +908,20 @@ def _url_expression(cls) -> ColumnElement[str]:
             ),
             (
                 cls.source == IssueSource.LAUNCHPAD,
-                func.concat(
-                    "https://bugs.launchpad.net/",
-                    cls.project,
-                    "/+bug/",
-                    cls.key,
+                case(
+                    (
+                        cls.project != "",
+                        func.concat(
+                            "https://bugs.launchpad.net/",
+                            cls.project,
+                            "/+bug/",
+                            cls.key,
+                        ),
+                    ),
+                    else_=func.concat(
+                        "https://launchpad.net/bugs/",
+                        cls.key,
+                    ),
                 ),
             ),
             else_="https://invalid",

backend/tests/controllers/issues/test_issue_url_parser.py

@@ -14,6 +14,7 @@
 # SPDX-License-Identifier: AGPL-3.0-only
 
 import pytest
+import requests_mock as req_mock
 from pydantic import HttpUrl
 
 from test_observer.controllers.issues.issue_url_parser import (
@@ -98,3 +99,70 @@ def test_from_url(url: str, expected: tuple[IssueSource, str, str] | None):
         assert expected is None
     else:
         assert result == expected
+
+
+def test_launchpad_short_url_resolves_project():
+    """launchpad.net/bugs/<id> should follow the redirect and return the project."""
+    with req_mock.Mocker() as m:
+        m.head(
+            "https://launchpad.net/bugs/1951586",
+            status_code=301,
+            headers={"Location": "https://bugs.launchpad.net/netplan/+bug/1951586"},
+        )
+        m.head(
+            "https://bugs.launchpad.net/netplan/+bug/1951586",
+            status_code=200,
+        )
+        result = issue_source_project_key_from_url(HttpUrl("https://launchpad.net/bugs/1951586"))
+    assert result == (IssueSource.LAUNCHPAD, "netplan", "1951586")
+
+
+def test_launchpad_short_url_with_source_package():
+    """+source/ paths in the resolved URL are handled correctly."""
+    with req_mock.Mocker() as m:
+        m.head(
+            "https://launchpad.net/bugs/2137746",
+            status_code=301,
+            headers={"Location": "https://bugs.launchpad.net/ubuntu/+source/linux-meta/+bug/2137746"},
+        )
+        m.head(
+            "https://bugs.launchpad.net/ubuntu/+source/linux-meta/+bug/2137746",
+            status_code=200,
+        )
+        result = issue_source_project_key_from_url(HttpUrl("https://launchpad.net/bugs/2137746"))
+    assert result == (IssueSource.LAUNCHPAD, "ubuntu", "2137746")
+
+
+def test_launchpad_short_url_bad_key():
+    """Non-numeric bug ID in launchpad.net/bugs/ path raises ValueError."""
+    with pytest.raises(ValueError):
+        issue_source_project_key_from_url(HttpUrl("https://launchpad.net/bugs/abc"))
+
+
+def test_launchpad_short_url_unknown_path():
+    """Unrecognised launchpad.net path raises ValueError."""
+    with pytest.raises(ValueError):
+        issue_source_project_key_from_url(HttpUrl("https://launchpad.net/unknown/1951586"))
+
+
+def test_launchpad_short_url_network_error():
+    """Network failure while resolving the redirect raises ValueError."""
+    import requests
+
+    with req_mock.Mocker() as m:
+        m.head("https://launchpad.net/bugs/1951586", exc=requests.ConnectionError("network down"))
+        with pytest.raises(ValueError, match="Could not resolve"):
+            issue_source_project_key_from_url(HttpUrl("https://launchpad.net/bugs/1951586"))
+
+
+def test_launchpad_short_url_unexpected_redirect_target():
+    """If the redirect resolves to an unexpected URL, ValueError is raised."""
+    with req_mock.Mocker() as m:
+        m.head(
+            "https://launchpad.net/bugs/1951586",
+            status_code=301,
+            headers={"Location": "https://example.com/unexpected"},
+        )
+        m.head("https://example.com/unexpected", status_code=200)
+        with pytest.raises(ValueError, match="unrecognised URL"):
+            issue_source_project_key_from_url(HttpUrl("https://launchpad.net/bugs/1951586"))