[PATCH v4 19/24] python: add devel package requirements to setuptools

[John Snow <jsnow@redhat.com>]

setuptools doesn't have a formal understanding of development requires,
but it has an optional feataures section. Fine; add a "devel" feature
and add the requirements to it.

To avoid duplication, we can modify pipenv to install qemu[devel]
instead. This enables us to run invocations like "pip install -e
.[devel]" and test the package on bleeding-edge packages beyond those
specified in Pipfile.lock.

Importantly, this also allows us to install the qemu development
packages in a non-networked mode: `pip3 install --no-index -e .[devel]`
will now fail if the proper development dependencies are not already
met. This can be useful for automated build scripts where fetching
network packages may be undesirable.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 python/Pipfile      |  5 +----
 python/Pipfile.lock | 14 +++++++++-----
 python/setup.cfg    |  9 +++++++++
 3 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/python/Pipfile b/python/Pipfile
index 214fb175e7a..e7acb8cefa4 100644
--- a/python/Pipfile
+++ b/python/Pipfile
@@ -4,10 +4,7 @@ url = "https://pypi.org/simple"
 verify_ssl = true
 
 [dev-packages]
-flake8 = ">=3.6.0"
-isort = ">=5.0.5"
-mypy = ">=0.770"
-pylint = ">=2.6.0"
+qemu = {editable = true, extras = ["devel"], path = "."}
 
 [packages]
 qemu = {editable = true,path = "."}
diff --git a/python/Pipfile.lock b/python/Pipfile.lock
index 4b4402f49e5..85b3124a491 100644
--- a/python/Pipfile.lock
+++ b/python/Pipfile.lock
@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "e38d142c3fadc2f2ed849e86f7ebd14e25974dc12228751490aef5a9ee074f2f"
+            "sha256": "eff562a688ebc6f3ffe67494dbb804b883e2159ad81c4d55d96da9f7aec13e91"
         },
         "pipfile-spec": 6,
         "requires": {
@@ -35,7 +35,7 @@
                 "sha256:749dbbd6bfd0cf1318af27bf97a14e28e5ff548ef8e5b1566ccfb25a11e7c839",
                 "sha256:aadae8761ec651813c24be05c6f7b4680857ef6afaae4651a4eccaef97ce6c3b"
             ],
-            "index": "pypi",
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3'",
             "version": "==3.8.4"
         },
         "importlib-metadata": {
@@ -51,7 +51,7 @@
                 "sha256:c729845434366216d320e936b8ad6f9d681aab72dc7cbc2d51bedc3582f3ad1e",
                 "sha256:fff4f0c04e1825522ce6949973e83110a6e907750cd92d128b0d14aaaadbffdc"
             ],
-            "index": "pypi",
+            "markers": "python_version >= '3.6' and python_version < '4.0'",
             "version": "==5.7.0"
         },
         "lazy-object-proxy": {
@@ -113,7 +113,7 @@
                 "sha256:e497a544391f733eca922fdcb326d19e894789cd4ff61d48b4b195776476c5cf",
                 "sha256:f5fdf935a46aa20aa937f2478480ebf4be9186e98e49cc3843af9a5795a49a25"
             ],
-            "index": "pypi",
+            "markers": "python_version >= '3.5'",
             "version": "==0.800"
         },
         "mypy-extensions": {
@@ -144,9 +144,13 @@
                 "sha256:bb4a908c9dadbc3aac18860550e870f58e1a02c9f2c204fdf5693d73be061210",
                 "sha256:bfe68f020f8a0fece830a22dd4d5dddb4ecc6137db04face4c3420a46a52239f"
             ],
-            "index": "pypi",
+            "markers": "python_version >= '3.5'",
             "version": "==2.6.0"
         },
+        "qemu": {
+            "editable": true,
+            "path": "."
+        },
         "six": {
             "hashes": [
                 "sha256:30639c035cdb23534cd4aa2dd52c3bf48f06e5f4a941509c8bafd8ce11080259",
diff --git a/python/setup.cfg b/python/setup.cfg
index bc90d52b9ca..11c361501e8 100644
--- a/python/setup.cfg
+++ b/python/setup.cfg
@@ -19,6 +19,15 @@ classifiers =
 python_requires = >= 3.6
 packages = find_namespace:
 
+[options.extras_require]
+# Run `pipenv lock` when changing these requirements.
+devel =
+    flake8 >= 3.6.0
+    isort >= 5.0.5
+    mypy >= 0.770
+    pylint >= 2.6.0
+
+
 [flake8]
 extend-ignore = E722  # Prefer pylint's bare-except checks to flake8's
 
-- 
2.29.2