Fix previous detection of empty arrays

1 files changed, 3 insertions, 2 deletions

diff --git a/setuptools/config/pyprojecttoml.py b/setuptools/config/pyprojecttoml.py
index 0ee1b8f9..e20d71d2 100644
--- a/setuptools/config/pyprojecttoml.py
+++ b/setuptools/config/pyprojecttoml.py
@@ -282,11 +282,12 @@ class _ConfigExpander:
         )
         # `None` indicates there is nothing in `tool.setuptools.dynamic` but the value
         # might have already been set by setup.py/extensions, so avoid overwriting.
-        self.project_cfg.update({k: v for k, v in obtained_dynamic.items() if v})
+        updates = {k: v for k, v in obtained_dynamic.items() if v is not None}
+        self.project_cfg.update(updates)
 
     def _ensure_previously_set(self, dist: "Distribution", field: str):
         previous = _PREVIOUSLY_DEFINED[field](dist)
-        if not previous and not self.ignore_option_errors:
+        if previous is None and not self.ignore_option_errors:
             msg = (
                 f"No configuration found for dynamic {field!r}.\n"
                 "Some dynamic fields need to be specified via `tool.setuptools.dynamic`"