Add package.readme properties to ensure retrocompatibility

poetry/core/packages/package.py

@@ -351,6 +351,26 @@ def urls(self) -> Dict[str, str]:
 
         return urls
 
+    @property
+    def readme(self) -> Path:
+        import warnings
+
+        warnings.warn(
+            "`readme` is deprecated: you are getting only the first readme file. Please use the plural form `readmes`",
+            DeprecationWarning,
+        )
+        return next(iter(self.readmes), None)
+
+    @readme.setter
+    def readme(self, path: Path) -> None:
+        import warnings
+
+        warnings.warn(
+            "`readme` is deprecated. Please assign a tuple to the plural form `readmes`",
+            DeprecationWarning,
+        )
+        self.readmes = (path,)
+
     def is_prerelease(self) -> bool:
         return self._version.is_unstable()
 

tests/packages/test_package.py

@@ -408,3 +408,22 @@ def test_only_with_dependency_groups(package_with_groups: Package):
 
     assert len(package.requires) == 2
     assert len(package.all_requires) == 2
+
+
+def test_get_readme_property_with_multiple_readme_files():
+    package = Package("foo", "0.1.0")
+
+    package.readmes = ("README.md", "HISTORY.md")
+    with pytest.deprecated_call():
+        assert package.readme == "README.md"
+
+
+def test_set_readme_property():
+    package = Package("foo", "0.1.0")
+
+    with pytest.deprecated_call():
+        package.readme = "README.md"
+
+    assert package.readmes == ("README.md",)
+    with pytest.deprecated_call():
+        assert package.readme == "README.md"