fix: don't force description and version field

pyproject.toml

@@ -4,7 +4,7 @@
 name = "pdm-backend"
 description = "The build backend used by PDM that supports latest packaging standards"
 authors = [
-  {name = "Frost Ming", email = "mianghong@gmail.com"}
+  { name = "Frost Ming", email = "me@frostming.com" }
 ]
 license = {text = "MIT"}
 requires-python = ">=3.7"
@@ -28,12 +28,13 @@ dependencies = [
 ]
 
 [project.urls]
-homepage = "https://pdm.fming.dev"
-repository = "https://github.com/pdm-project/pdm-backend"
+Homepage = "https://github.com/pdm-project/pdm-backend"
+Repository = "https://github.com/pdm-project/pdm-backend"
+Documentation = "https://pdm-backend.fming.dev"
 
-[project.optional-dependencies]
-[tool.pdm]
-version = {source = "file", path = "src/pdm/backend/__init__.py"}
+[tool.pdm.version]
+source = "file"
+path = "src/pdm/backend/__init__.py"
 
 [tool.pdm.build]
 includes = ["src"]

src/pdm/backend/hooks/setuptools.py

@@ -126,8 +126,8 @@ def format_setup_py(self, context: Context) -> str:
         meta = context.config.metadata
         kwargs = {
             "name": meta["name"],
-            "version": meta["version"],
-            "description": meta["description"],
+            "version": meta.get("version", "0.0.0"),
+            "description": meta.get("description", "UNKNOWN"),
             "url": (meta.get("project-urls", {})).get("homepage", ""),
         }