Remove setup.py develop command (#6424)

* Remove setup.py develop command.

* Protect from setuptools>=80 incompatibility.

* Relocate What's New entry.

Author: trexfeathers

benchmarks/asv_delegated.py

@@ -41,6 +41,24 @@ def _prep_env_override(self, env_parent_dir: Path) -> Path:
         # The project checkout.
         build_dir = Path(self._build_root) / self._repo_subdir
 
+        # Older iterations of setup.py are incompatible with setuptools>=80.
+        #  (Most dependencies are protected by lock-files, but build
+        #   dependencies in pyproject.toml are independent).
+        setup_py = build_dir / "setup.py"
+        pyproject = build_dir / "pyproject.toml"
+        if setup_py.is_file() and "setuptools.command.develop" in setup_py.read_text():
+            with pyproject.open("r+") as file_write:
+                lines = file_write.readlines()
+                for i, line in enumerate(lines):
+                    if line == "requires = [\n":
+                        next_line = lines[i + 1]
+                        indent = next_line[: len(next_line) - len(next_line.lstrip())]
+
+                        lines.insert(i + 1, f'{indent}"setuptools<80",\n')
+                        break
+                file_write.seek(0)
+                file_write.writelines(lines)
+
         class Mode(enum.Enum):
             """The scenarios where the correct env setup script is known."""
 

docs/src/whatsnew/latest.rst

@@ -36,7 +36,10 @@ This document explains the changes made to Iris for this release
 🐛 Bugs Fixed
 =============
 
-#. N/A
+#. `@trexfeathers`_ removed the custom ``setup.py develop`` command, since
+   Setuptools are deprecating ``develop``; developers should instead
+   use ``pip install -e .``. See `Running setuptools commands`_ for more.
+   (:pull:`6424`)
 
 
 💣 Incompatible Changes
@@ -85,4 +88,6 @@ This document explains the changes made to Iris for this release
 
 
 .. comment
-    Whatsnew resources in alphabetical order:
+    Whatsnew resources in alphabetical order:
+
+.. _Running setuptools commands: https://setuptools.pypa.io/en/latest/deprecated/commands.html

setup.py

@@ -5,7 +5,6 @@
 
 from setuptools import Command, setup
 from setuptools.command.build_py import build_py
-from setuptools.command.develop import develop
 
 
 class BaseCommand(Command):
@@ -49,8 +48,7 @@ def finalize_options(self):
             cmd.finalize_options(self)
 
             if not hasattr(self, "editable_mode") or self.editable_mode is None:
-                # Default to editable i.e., applicable to "std_names" and
-                # and "develop" commands.
+                # Default to editable i.e., applicable to "std_names".
                 self.editable_mode = True
 
         def run(self):
@@ -76,7 +74,6 @@ def run(self):
 
 
 custom_commands = {
-    "develop": custom_command(develop),
     "build_py": custom_command(build_py),
     "std_names": custom_command(BaseCommand, help="generate CF standard names"),
 }