Fix `tox -e docs` for macOS (#9765)

* Fix `tox -e docs` for macOS

Co-authored-by: Jake Lishman <jake@binhbar.com>

* Fix two issues. Duh, thanks Jake

* Update Azure job to set RUST_DEBUG

Not strictly necessary since Tox already sets it. But makes things consistent and avoids accidentally
removing this in the future

---------

Co-authored-by: Jake Lishman <jake@binhbar.com>

.azure/docs-linux.yml

@@ -9,6 +9,7 @@ jobs:
 
     variables:
       PIP_CACHE_DIR: $(Pipeline.Workspace)/.pip
+      RUST_DEBUG: 1
 
     steps:
       - checkout: self
@@ -29,8 +30,6 @@ jobs:
       - bash: |
           tox -edocs
         displayName: 'Run Docs build'
-        env:
-          SETUPTOOLS_ENABLE_FEATURES: "legacy-editable"
 
       - task: ArchiveFiles@2
         inputs:

setup.py

@@ -14,8 +14,7 @@
 
 import os
 import re
-import sys
-from setuptools import setup, find_packages, Extension
+from setuptools import setup, find_packages
 from setuptools_rust import Binding, RustExtension
 
 
@@ -100,7 +99,14 @@ setup(
         "Source Code": "https://github.com/Qiskit/qiskit-terra",
     },
     rust_extensions=[
-        RustExtension("qiskit._accelerate", "crates/accelerate/Cargo.toml", binding=Binding.PyO3)
+        RustExtension(
+            "qiskit._accelerate",
+            "crates/accelerate/Cargo.toml",
+            binding=Binding.PyO3,
+            # If RUST_DEBUG is set, force compiling in debug mode. Else, use the default behavior
+            # of whether it's an editable installation.
+            debug=True if os.getenv("RUST_DEBUG") == "1" else None,
+        )
     ],
     zip_safe=False,
     entry_points={

tox.ini

@@ -67,24 +67,16 @@ commands =
   coverage3 report
 
 [testenv:docs]
+# Editable mode breaks macOS: https://github.com/sphinx-doc/sphinx/issues/10943
+usedevelop = False
 basepython = python3
 setenv =
   {[testenv]setenv}
   QISKIT_SUPPRESS_PACKAGING_WARNINGS=Y
+  RUST_DEBUG=1  # Faster to compile.
 deps =
   setuptools_rust  # This is work around for the bug of tox 3 (see #8606 for more details.)
   -r{toxinidir}/requirements-dev.txt
   qiskit-aer
 commands =
   sphinx-build -W -j auto -T --keep-going -b html docs/ docs/_build/html {posargs}
-
-[pycodestyle]
-max-line-length = 105
-# default ignores + E741 because of opflow global variable I
-# + E203 because of a difference of opinion with black
-# codebase does currently comply with: E133, E242, E704, W505
-ignore = E121, E123, E126, E133, E226, E241, E242, E704, W503, W504, W505, E741, E203
-
-[flake8]
-max-line-length = 105
-extend-ignore = E203, E741