First implementation of tox_to_nox for tox 4

nox/tox4_to_nox.jinja2

@@ -0,0 +1,34 @@
+import nox
+
+{% for envname, envconfig in config.items()|sort: %}
+@nox.session({%- if envconfig.base_python %}python='{{envconfig.base_python}}'{%- endif %})
+def {{fixname(envname)}}(session):
+    {%- if envconfig.description != '' %}
+    """{{envconfig.description}}"""
+    {%- endif %}
+    {%- set envs = envconfig.get('set_env', {}) -%}
+    {%- for key, value in envs.items()|sort: %}
+    session.env['{{key}}'] = '{{value}}'
+    {%- endfor %}
+
+    {%- if envconfig.deps %}
+    session.install({{wrapjoin(envconfig.deps)}})
+    {%- endif %}
+
+    {%- if not envconfig.skip_install %}
+    {%- if envconfig.use_develop %}
+    session.install('-e', '.')
+    {%- else %}
+    session.install('.')
+    {%- endif -%}
+    {%- endif %}
+
+    {#- TODO: implement session.chdir -#}
+    {%- if envconfig.changedir and config.toxinidir.bestrelpath(envconfig.changedir) != '.' %}
+    session.chdir('{{config.toxinidir.bestrelpath(envconfig.changedir)}}')
+    {%- endif %}
+
+    {%- for command in envconfig.commands %}
+    session.run('{{command}}')
+    {%- endfor %}
+{% endfor %}

nox/tox_to_nox.py

@@ -21,20 +21,31 @@
 from typing import Any, Iterator
 
 import jinja2
-import tox.config
+from tox import __version__ as TOX_VERSION
 
-_TEMPLATE = jinja2.Template(
-    pkgutil.get_data(__name__, "tox_to_nox.jinja2").decode("utf-8"),  # type: ignore[union-attr]
-    extensions=["jinja2.ext.do"],
-)
+TOX3 = TOX_VERSION[0] == "3"
+
+if TOX3:
+    import tox.config
+    _TEMPLATE = jinja2.Template(
+        pkgutil.get_data(__name__, "tox_to_nox.jinja2").decode("utf-8"),  # type: ignore[union-attr]
+        extensions=["jinja2.ext.do"],
+    )
+else:
+    from subprocess import check_output
+    from configparser import ConfigParser
+    _TEMPLATE = jinja2.Template(
+        pkgutil.get_data(__name__, "tox4_to_nox.jinja2").decode("utf-8"),  # type: ignore[union-attr]
+        extensions=["jinja2.ext.do"],
+    )
 
 
 def wrapjoin(seq: Iterator[Any]) -> str:
     return ", ".join([f"'{item}'" for item in seq])
 
 
 def fixname(envname: str) -> str:
-    envname = envname.replace("-", "_")
+    envname = envname.replace("-", "_").replace(":", "_")
     if not envname.isidentifier():
         print(
             f"Environment {envname!r} is not a valid nox session name.\n"
@@ -49,7 +60,37 @@ def main() -> None:
 
     args = parser.parse_args()
 
-    config = tox.config.parseconfig([])
+    if TOX3:
+        config = tox.config.parseconfig([])
+    else:
+        output = check_output(["tox", "config"], text=True)
+        original_config = ConfigParser()
+        original_config.read_string(output)
+        config = {}
+
+        for name, section in original_config.items():
+            config[name] = dict(section)
+            # Convert set_env from string to dict
+            set_env = {}
+            for var in section.get("set_env", "").strip().splitlines():
+                k, v = var.split("=")
+                if k not in ("PYTHONHASHSEED", "TOX_ENV_DIR", "TOX_ENV_NAME"):
+                    set_env[k] = v
+
+            if set_env:
+                config[name]["set_env"] = set_env
+
+            for option in "deps", "commands":
+                if isinstance(config[name].get(option), str):
+                    config[name][option] = config[name][option].strip().splitlines()
+
+            for option in "skip_install", "use_develop":
+                if config[name].get(option):
+                    if config[name][option] == "False":
+                        config[name][option] = False
+                    else:
+                        config[name][option] = True
+
     output = _TEMPLATE.render(config=config, wrapjoin=wrapjoin, fixname=fixname)
 
     with open(args.output, "w") as outfile:

pyproject.toml

@@ -50,7 +50,7 @@ classifiers = [
 [project.optional-dependencies]
 tox_to_nox = [
   "jinja2",
-  "tox<4",
+  "tox",
 ]
 
 [project.urls]