Support environment.python.requires option in manifest (#648)

Author: amol-

CHANGELOG.md

@@ -4,6 +4,13 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [??] - ??
+
+### Added
+
+- `rsconnect` now detects Python interpreter version requirements from
+  `.python-version`, `pyproject.toml` and `setup.cfg`
+
 ## [1.25.2] - 2025-02-26
 
 ### Fixed

README.md

@@ -219,24 +219,34 @@ ensuring that you use the same Python that you use to run your Jupyter Notebook:
 #### Python Version
 
 When deploying Python content to Posit Connect,
-the server will require matching `<MAJOR.MINOR>` versions of Python. For example,
-a server with only Python 3.9 installed will fail to match content deployed with
-Python 3.8. Your administrator may also enable exact Python version matching which
-will be stricter and require matching major, minor, and patch versions. For more
-information see the [Posit Connect Admin Guide chapter titled Python Version
+the server will require a version of Python that matches the content
+requirements.
+
+For example, a server with only Python 3.9 installed will fail to match content
+that requires Python 3.8.
+
+`rsconnect` supports detecting Python version requirements in several ways:
+    1. A `.python-version` file exists. In such case
+       `rsconnect` will use its content to determine the python version requirement.
+    2. A `pyproject.toml` with a `project.requires-python` field exists.
+       In such case the requirement specified in the field will be used
+       if no `.python-version` file exists.
+    3. A `setup.cfg` with an `options.python_requires` field exists.
+       In such case the requirement specified in the field will be used
+       if **1** or **2** were not already satisfied.
+    4. If no other source of version requirement was found, then
+       the interpreter in use is considered the one required to run the content.
+
+On Posit Connect `>=2025.03.0` the requirement detected by `rsconnect` is
+always respected. Older Connect versions will instead rely only on the
+python version used to deploy the content to determine the requirement.
+
+For more information see the [Posit Connect Admin Guide chapter titled Python Version
 Matching](https://docs.posit.co/connect/admin/python/#python-version-matching).
 
-We recommend installing a version of Python on your client that is also available
-in your Connect installation. If that's not possible, you can override
-rsconnect-python's detected Python version and request a version of Python
-that is installed in Connect, For example, this command:
-
-```bash
-rsconnect deploy api --override-python-version 3.11.5 my-api/
-```
-
-will deploy the content in `my-api` while requesting that Connect
-use Python version 3.11.5.
+We recommend providing a `pyproject.toml` with a `project.requires-python` field
+if the deployed content is an installable package and a `.python-version` file
+for plain directories.
 
 > **Note**
 > The packages and package versions listed in `requirements.txt` must be

rsconnect/actions.py

@@ -31,13 +31,12 @@
 
 from . import api
 from .bundle import (
-    create_python_environment,
     get_default_entrypoint,
     make_api_bundle,
     make_quarto_source_bundle,
     read_manifest_file,
 )
-from .environment import Environment, EnvironmentException
+from .environment import Environment
 from .exception import RSConnectException
 from .log import VERBOSE, logger
 from .models import AppMode, AppModes
@@ -78,8 +77,6 @@ def failed(err: str):
         passed()
     except RSConnectException as exc:
         failed("Error: " + exc.message)
-    except EnvironmentException as exc:
-        failed("Error: " + str(exc))
     except Exception as exc:
         traceback.print_exc()
         failed("Internal error: " + str(exc))
@@ -375,7 +372,7 @@ def deploy_app(
             )
         )
 
-    environment = create_python_environment(
+    environment = Environment.create_python_environment(
         directory,  # pyright: ignore
         force_generate,
         python,

rsconnect/api.py

@@ -51,7 +51,8 @@
     from typing_extensions import NotRequired, TypedDict
 
 from . import validation
-from .bundle import _default_title, fake_module_file_from_directory
+from .bundle import _default_title
+from .environment import fake_module_file_from_directory
 from .certificates import read_certificate_file
 from .exception import DeploymentFailedException, RSConnectException
 from .http_support import CookieJar, HTTPResponse, HTTPServer, JsonData, append_to_path