tox3: Support provision of tox 4 with the min_version option (#2714)

Fixes https://github.com/tox-dev/tox/issues/2661

8 files changed, 84 insertions, 26 deletions

diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
index a52a041c..b848af03 100644
--- a/.github/workflows/check.yml
+++ b/.github/workflows/check.yml
@@ -1,7 +1,7 @@
 name: check
 on:
   push:
-    branches: [master, 'test-me-*']
+    branches: [legacy, 'test-me-*']
     tags:
   pull_request:
   schedule:
diff --git a/docs/changelog/2661.feature.rst b/docs/changelog/2661.feature.rst
new file mode 100644
index 00000000..15e28720
--- /dev/null
+++ b/docs/changelog/2661.feature.rst
@@ -0,0 +1 @@
+Support provision of tox 4 with the ``min_version`` option - by :user:`hroncok`
diff --git a/docs/config.rst b/docs/config.rst
index d3b28ff7..d71048cb 100644
--- a/docs/config.rst
+++ b/docs/config.rst
@@ -43,6 +43,12 @@ Global settings are defined under the ``tox`` section as:
    When tox is invoked with the ``--no-provision`` flag,
    the provision won't be attempted, tox will fail instead.
 
+   .. versionchanged:: 3.27.2
+
+    ``min_version`` has the same meaning and usage as ``minversion``
+    to support a best effort provision of tox 4.
+
+
 .. conf:: requires ^ LIST of PEP-508
 
     .. versionadded:: 3.2.0
diff --git a/src/tox/config/__init__.py b/src/tox/config/__init__.py
index 75b9ab92..fdf6e62c 100644
--- a/src/tox/config/__init__.py
+++ b/src/tox/config/__init__.py
@@ -1344,6 +1344,10 @@ class ParseIni(object):
     def handle_provision(self, config, reader):
         config.requires = reader.getlist("requires")
         config.minversion = reader.getstring("minversion", None)
+        # tox 4 prefers the min_version name of this option.
+        # We check is as well in case the config is intended for tox 4.
+        # This allows to make a *best effort* attempt to provision tox 4 from tox 3.
+        config.minversion = config.minversion or reader.getstring("min_version", None)
         config.provision_tox_env = name = reader.getstring("provision_tox_env", ".tox")
         min_version = "tox >= {}".format(config.minversion or Version(tox.__version__).public)
         deps = self.ensure_requires_satisfied(config, config.requires, min_version)
diff --git a/tests/integration/test_provision_int.py b/tests/integration/test_provision_int.py
index f1763e49..ec682978 100644
--- a/tests/integration/test_provision_int.py
+++ b/tests/integration/test_provision_int.py
@@ -25,7 +25,7 @@ def test_provision_missing(initproj, cmd):
             "tox.ini": """\
                 [tox]
                 skipsdist=True
-                minversion = 3.7.0
+                minversion = 3.7.0,<4
                 requires =
                     setuptools == 40.6.3
                 [testenv]
@@ -54,7 +54,7 @@ def test_provision_from_pyvenv(initproj, cmd, monkeypatch):
             "tox.ini": """\
                 [tox]
                 skipsdist=True
-                minversion = 3.7.0
+                minversion = 3.7.0,<4
                 requires =
                     setuptools == 40.6.3
                 [testenv]
@@ -68,6 +68,31 @@ def test_provision_from_pyvenv(initproj, cmd, monkeypatch):
     assert ".tox/.tox/bin/python -m virtualenv" in result.out
 
 
+@pytest.mark.skipif(
+    "sys.version_info < (3, 7)",
+    reason="tox 4 only supports Python >= 3.7",
+)
+def test_provision_tox_4(initproj, cmd, monkeypatch):
+    initproj(
+        "pkg123-0.7",
+        filedefs={
+            "tox.ini": """\
+                [tox]
+                no_package=True
+                min_version = 4
+                [testenv]
+                commands=python -c "import os; print('assert this')"
+            """,
+        },
+    )
+    result = cmd("-e", "py", "-vvv")
+    # result.assert_success() has some assumptions about output that tox 4 doesn't follow
+    assert result.ret == 0, result.output()
+    assert "assert this" in result.out
+    # this exact line is only in tox 3:
+    assert "  congratulations :)" not in result.out.splitlines()
+
+
 @pytest.mark.skipif(INFO.IS_PYPY, reason="TODO: process numbers work differently on pypy")
 @pytest.mark.skipif(
     "sys.platform == 'win32'",
@@ -83,7 +108,7 @@ def test_provision_interrupt_child(initproj, monkeypatch, capfd, signal_type):
             "tox.ini": """
                     [tox]
                     skipsdist=True
-                    minversion = 3.7.0
+                    minversion = 3.7.0,<4
                     requires = setuptools == 40.6.3
                                tox == 3.7.0
                     [testenv:b]
@@ -144,7 +169,7 @@ def test_provision_race(initproj, cmd, monkeypatch):
             "tox.ini": """\
                 [tox]
                 skipsdist=True
-                minversion = 3.7.0
+                minversion = 3.7.0,<4
                 requires =
                     setuptools == 40.6.3
                 [testenv]
diff --git a/tests/unit/session/test_parallel.py b/tests/unit/session/test_parallel.py
index e08ef1f0..3fa2331b 100644
--- a/tests/unit/session/test_parallel.py
+++ b/tests/unit/session/test_parallel.py
@@ -272,8 +272,7 @@ def test_parallel_result_json_concurrent(cmd, parallel_project, tmp_path):
             # needs to be process to have it's own stdout
             invoke_result[thread_name] = subprocess.check_output(
                 [sys.executable, "-m", "tox", "-p", "all", "--result-json", str(result_json)],
-                universal_newlines=True,
-            )
+            ).decode("utf-8")
         except subprocess.CalledProcessError as exception:
             invoke_result[thread_name] = exception
 
diff --git a/tests/unit/session/test_provision.py b/tests/unit/session/test_provision.py
index 24f7b3d8..0ebaf8af 100644
--- a/tests/unit/session/test_provision.py
+++ b/tests/unit/session/test_provision.py
@@ -27,14 +27,21 @@ def next_tox_major():
     return "10.0.0"
 
 
-def test_provision_min_version_is_requires(newconfig, next_tox_major):
+@pytest.fixture(scope="session", params=["minversion", "min_version"])
+def minversion_option(request):
+    """both possible names for the minversion config option"""
+    return request.param
+
+
+def test_provision_min_version_is_requires(newconfig, minversion_option, next_tox_major):
     with pytest.raises(MissingRequirement) as context:
         newconfig(
             [],
             """\
             [tox]
-            minversion = {}
+            {} = {}
             """.format(
+                minversion_option,
                 next_tox_major,
             ),
         )
@@ -49,17 +56,20 @@ def test_provision_min_version_is_requires(newconfig, next_tox_major):
     assert config.ignore_basepython_conflict is False
 
 
-def test_provision_config_has_minversion_and_requires(newconfig, next_tox_major):
+def test_provision_config_has_minversion_and_requires(
+    newconfig, minversion_option, next_tox_major
+):
     with pytest.raises(MissingRequirement) as context:
         newconfig(
             [],
             """\
             [tox]
-            minversion = {}
+            {} = {}
             requires =
                 setuptools > 2
                 pip > 3
             """.format(
+                minversion_option,
                 next_tox_major,
             ),
         )
@@ -89,17 +99,18 @@ def test_provision_tox_change_name(newconfig):
     assert config.provision_tox_env == "magic"
 
 
-def test_provision_basepython_global_only(newconfig, next_tox_major):
+def test_provision_basepython_global_only(newconfig, minversion_option, next_tox_major):
     """we don't want to inherit basepython from global"""
     with pytest.raises(MissingRequirement) as context:
         newconfig(
             [],
             """\
             [tox]
-            minversion = {}
+            {} = {}
             [testenv]
             basepython = what
             """.format(
+                minversion_option,
                 next_tox_major,
             ),
         )
@@ -108,17 +119,18 @@ def test_provision_basepython_global_only(newconfig, next_tox_major):
     assert base_python == sys.executable
 
 
-def test_provision_basepython_local(newconfig, next_tox_major):
+def test_provision_basepython_local(newconfig, minversion_option, next_tox_major):
     """however adhere to basepython when explicitly set"""
     with pytest.raises(MissingRequirement) as context:
         newconfig(
             [],
             """\
             [tox]
-            minversion = {}
+            {} = {}
             [testenv:.tox]
             basepython = what
             """.format(
+                minversion_option,
                 next_tox_major,
             ),
         )
@@ -199,14 +211,17 @@ def test_provision_does_not_fail_with_no_provision_no_reason(cmd, initproj, json
 
 
 @parametrize_json_path
-def test_provision_fails_with_no_provision_next_tox(cmd, initproj, next_tox_major, json_path):
+def test_provision_fails_with_no_provision_next_tox(
+    cmd, initproj, minversion_option, next_tox_major, json_path
+):
     p = initproj(
         "test-0.1",
         {
             "tox.ini": """\
                              [tox]
-                             minversion = {}
+                             {} = {}
                              """.format(
+                minversion_option,
                 next_tox_major,
             )
         },
@@ -238,17 +253,21 @@ def test_provision_fails_with_no_provision_missing_requires(cmd, initproj, json_
 
 
 @parametrize_json_path
-def test_provision_does_not_fail_with_satisfied_requires(cmd, initproj, next_tox_major, json_path):
+def test_provision_does_not_fail_with_satisfied_requires(
+    cmd, initproj, minversion_option, json_path
+):
     p = initproj(
         "test-0.1",
         {
             "tox.ini": """\
                              [tox]
-                             minversion = 0
+                             {} = 0
                              requires =
                                  setuptools > 2
                                  pip > 3
-                             """
+                             """.format(
+                minversion_option
+            )
         },
     )
     result = cmd("--no-provision", *([json_path] if json_path else []))
@@ -257,17 +276,20 @@ def test_provision_does_not_fail_with_satisfied_requires(cmd, initproj, next_tox
 
 
 @parametrize_json_path
-def test_provision_fails_with_no_provision_combined(cmd, initproj, next_tox_major, json_path):
+def test_provision_fails_with_no_provision_combined(
+    cmd, initproj, minversion_option, next_tox_major, json_path
+):
     p = initproj(
         "test-0.1",
         {
             "tox.ini": """\
                              [tox]
-                             minversion = {}
+                             {} = {}
                              requires =
                                  setuptools > 2
                                  pip > 3
                              """.format(
+                minversion_option,
                 next_tox_major,
             )
         },
@@ -389,15 +411,16 @@ def space_path2url(path):
     return urljoin("file:", pathname2url(os.path.abspath(at_path)))
 
 
-def test_provision_does_not_occur_in_devenv(newconfig, next_tox_major):
+def test_provision_does_not_occur_in_devenv(newconfig, minversion_option, next_tox_major):
     """Adding --devenv should not change the directory where provisioning occurs"""
     with pytest.raises(MissingRequirement) as context:
         newconfig(
             ["--devenv", "my_devenv"],
             """\
             [tox]
-            minversion = {}
+            {} = {}
             """.format(
+                minversion_option,
                 next_tox_major,
             ),
         )
diff --git a/tox.ini b/tox.ini
index c2557528..aad28783 100644
--- a/tox.ini
+++ b/tox.ini
@@ -57,7 +57,7 @@ commands =
 
 [testenv:coverage]
 description = [run locally after tests]: combine coverage data and create report;
-    generates a diff coverage against origin/master (can be changed by setting DIFF_AGAINST env var)
+    generates a diff coverage against origin/legacy (can be changed by setting DIFF_AGAINST env var)
 passenv =
     {[testenv]passenv}
     DIFF_AGAINST
@@ -73,7 +73,7 @@ commands =
     coverage report -m
     coverage xml -o {toxworkdir}/coverage.xml
     coverage html -d {toxworkdir}/htmlcov
-    diff-cover --compare-branch {env:DIFF_AGAINST:origin/master} {toxworkdir}/coverage.xml
+    diff-cover --compare-branch {env:DIFF_AGAINST:origin/legacy} {toxworkdir}/coverage.xml
 depends = py27, py35, py36, py37, py38, py39, py310, py311, pypy, pypy3
 
 [testenv:docs]