Don't require `setuptools_rust` at runtime (#13952)

1 files changed, 16 insertions, 1 deletions

diff --git a/synapse/util/check_dependencies.py b/synapse/util/check_dependencies.py
index 66f1da7502..3b1e205700 100644
--- a/synapse/util/check_dependencies.py
+++ b/synapse/util/check_dependencies.py
@@ -66,6 +66,21 @@ def _is_dev_dependency(req: Requirement) -> bool:
     )
 
 
+def _should_ignore_runtime_requirement(req: Requirement) -> bool:
+    # This is a build-time dependency. Irritatingly, `poetry build` ignores the
+    # requirements listed in the [build-system] section of pyproject.toml, so in order
+    # to support `poetry install --no-dev` we have to mark it as a runtime dependency.
+    # See discussion on https://github.com/python-poetry/poetry/issues/6154 (it sounds
+    # like the poetry authors don't consider this a bug?)
+    #
+    # In any case, workaround this by ignoring setuptools_rust here. (It might be
+    # slightly cleaner to put `setuptools_rust` in a `build` extra or similar, but for
+    # now let's do something quick and dirty.
+    if req.name == "setuptools_rust":
+        return True
+    return False
+
+
 class Dependency(NamedTuple):
     requirement: Requirement
     must_be_installed: bool
@@ -77,7 +92,7 @@ def _generic_dependencies() -> Iterable[Dependency]:
     assert requirements is not None
     for raw_requirement in requirements:
         req = Requirement(raw_requirement)
-        if _is_dev_dependency(req):
+        if _is_dev_dependency(req) or _should_ignore_runtime_requirement(req):
             continue
 
         # https://packaging.pypa.io/en/latest/markers.html#usage notes that