add initial page with overview of changes in EasyBuild v5.0

docs/easybuild-v5/overview-of-changes.md

@@ -0,0 +1,154 @@
+# Overview of changes in EasyBuild version 5.0 {: #overview }
+
+!!! warning
+    EasyBuild 5.0 is currently still under development, via the `5.0.x` branches in the EasyBuild GitHub repositories.
+
+    We intend to update this page regularly as the [planned changes][eb5_plans] are being implemented and when there
+    are [proposed changes][eb5_proposals] where we are requesting community feedback.
+
+This page provides a concise overview of the most prominent changes in EasyBuild version 5.0,
+which can be categorized as:
+
+* [Significant enhancements][significant_enhancements]
+* [Backward-incompatible changes][backwards_incompatible]
+* [Deprecated functionality][deprecated_v5]
+
+For in-depth details on a particular change, see the pull requests that are linked from each of the subsections below.
+
+---
+
+## Planned and proposed changes for EasyBuild v5.0 {: #eb5_changes }
+
+At the [EasyBuild User Meeting](https://easybuild.io/eum23), Simon Branford set out the
+[roadmap for EasyBuild v5.0](https://easybuild.io/eum23/#easybuild5).
+
+### Proposed changes for EasyBuild v5.0 {: #eb5_proposals }
+
+There are several proposed changes where the EasyBuild maintainers are seeking community feedback. If you wish to provide
+feedback then please comment in the GitHub issue for the proposal.
+
+* Minimum supported Lmod Version: _proposal forthcoming_
+* Toolchain Support Policy: _proposal forthcoming_
+
+### Planned changes for EasyBuild v5.0 {: #eb5_plans }
+
+* [enable `--trace` by default](https://github.com/easybuilders/easybuild-framework/pull/4250)
+
+!!! note
+    This list is the major planned changes. It is not intended to be a complete list of all changes that are
+    planned for EasyBuild v5.0.
+
+### Tracking development of EasyBuild v5.0
+
+* [GitHub Project board for EasyBuild v5.0](https://github.com/orgs/easybuilders/projects/18)
+
+---
+
+## Significant enhancements in EasyBuild v5.0 {: #significant_enhancements }
+
+Various significant enhancements are included in EasyBuild v5.0, including:
+
+* *(no significant enhancements implemented so far in the `5.0.x` branches)*
+
+---
+
+## Backwards-incompatible changes in EasyBuild v4.0 {: #backwards_incompatible }
+
+A number of *backwards-incompatible* changes are being made in EasyBuild v5.0:
+
+* [Support for Python 2.7 is removed -- Python 3.6+ is required][py36]
+* [Deprecated EasyBuild bootstrap script is removed][bootstrap_script]
+* [Experimental support for the .yeb easyconfig format is removed][yeb]
+
+---
+
+### Support for Python 2.7 is removed -- Python 3.6+ is required {: #py36 }
+
+EasyBuild 5.0 requires Python >= 3.6 to run.
+
+Running EasyBuild with Python 2.7 or a Python 3 version older than Python 3.6 is no longer supported.
+
+Trying to run EasyBuild with a Python version that is too old will result in an error:
+
+```log
+ERROR: No compatible 'python' command found via $PATH (EasyBuild requires Python 3.6+)
+```
+
+Python 2.7 has been [end-of-life since 1 Jan 2020](https://www.python.org/doc/sunset-python-2),
+and dropping compatibility with Python 2.7 and Python 3.5 enabled some significant code cleanup
+(see [easybuild-framework PR #4229](https://github.com/easybuilders/easybuild-framework/pull/4229)).
+
+The [results of the 6th EasyBuild User Survey (2022)](https://easybuild.io/user_survey) show that the impact of
+this breaking change on the EasyBuild community should be very limited, since:
+
+* Only ~13% of survey participants were still running EasyBuild on top of Python 2.7;
+* No survey participants reported using Python 3.5;
+* Over 85% of survey participants reported using Python 3.6, or a more recent version of Python 3;
+* Only 3 out of 118 survey participants (~2.5%) reported that dropping support for running EasyBuild
+  on top of Python 2 would be *problematic* for them;
+
+Along with actively removing code that was only required to retain compatibility with Python 2.7 or 3.5,
+the `easybuild.tools.py2vs3` module that was introduced to facilitate supporting both Python 2.7 and Python 3
+has been deprecated ([see also below][py2vs3]).
+
+---
+
+### Deprecated EasyBuild bootstrap script is removed {: #bootstrap_script }
+
+The EasyBuild bootstrap script has been removed (see [easybuild-framework PR #4233](https://github.com/easybuilders/easybuild-framework/pull/4233)).
+Please see the [installation page][installation] for the suggested methods for installing EasyBuild.
+
+---
+
+### Experimental support for the .yeb easyconfig format is removed {: #yeb }
+
+Support for the experimental `.yeb` easyconfig format has been removed (see [easybuild-framework PR #4237](https://github.com/easybuilders/easybuild-framework/pull/4237)).
+This format allowed easyconfigs to be specified in YAML. However, there has been no recent development of this
+format and little suggestion that anyone was using it.
+
+---
+
+## Deprecated functionality in EasyBuild v5.0 {: #deprecated_v5 }
+
+Some functionality is being deprecated in EasyBuild v5.0, and will no longer be supported in EasyBuild v6.0:
+
+* [`easybuild.tools.py2vs3` module][py2vs3]
+
+If you trigger any deprecated functionality, a warning message will be printed.
+
+---
+
+### `easybuild.tools.py2vs3` module {: #py2vs3 }
+
+[easybuild-framework PR #4229](https://github.com/easybuilders/easybuild-framework/pull/4229)
+
+The following table lists the changes required to replace imports from the the `py2vs3` module.
+
+| `from easybuild.tools.py2vs3 import ...` | Replacement |
+|--|--|
+| `ascii_letters` | `from string import ascii_letters` |
+| `ascii_lowercase` | `from string import ascii_lowercase` |
+| `build_opener` | `from urllib.request import build_opener` |
+| `ConfigParser` | `from configparser import ConfigParser` |
+| `configparser` | `import configparser` |
+| `create_base_metaclass` | `from easybuild.base.wrapper import create_base_metaclass` |
+| `extract_method_name` | No import required. Replace `extract_method_name(method)` with `'_'.join(method.__code__.co_names)` |
+| `HTMLParser` | `from html.parser import HTMLParser` |
+| `HTTPError` | `from urllib.request import HTTPError` |
+| `HTTPSHandler` | `from urllib.request import HTTPSHandler` |
+| `json_loads` | `from json import loads` and rename `json_loads` to `loads` |
+| `Mapping` | `from collections.abc import Mapping` |
+| `mk_wrapper_baseclass` | `from easybuild.base.wrapper import mk_wrapper_baseclass` |
+| `OrderedDict` | `from collections import OrderedDict` |
+| `raise_with_traceback` | No import required. Replace `raise_with_traceback(exception, message, tb)` with `raise exception(message).with_traceback(tb)` |
+| `reload` | `from importlib import reload` |
+| `Request` | `from urllib.request import Request` |
+| `string_type` | No import required. Use `str` directly. |
+| `StringIO` | `from io import StringIO` |
+| `std_urllib` | `import urllib.request as std_urllib` |
+| `subprocess_popen_text` | `from easybuild.tools.run import subprocess_popen_text` |
+| `subprocess_terminate` | `from easybuild.tools.run import subprocess_terminate` |
+| `urlencode` | `from urllib.parse import urlencode` |
+| `URLError` | `from urllib.request import URLError` |
+| `urlopen` | `from urllib.request import urlopen` |
+

docs/writing-yeb-easyconfig-files.md

@@ -1,12 +1,7 @@
-# Writing easyconfig files in YAML syntax (`.yeb` format) **[IN DEVELOPMENT]** {: #easyconfig_yeb_format }
+# Writing easyconfig files in YAML syntax (`.yeb` format) **Deprecated** {: #easyconfig_yeb_format }
 
-!!! note
-    Because support for easyconfig files in YAML syntax (a.k.a. `.yeb` files) is still *in development*,
-    using them currently requires enabling the use of experimental features (`--experimental`),
-    see also [Experimental features][experimental_features].
-
-    An up-to-date overview of current progress on support for `.yeb` easyconfigs is available at
-    <https://github.com/easybuilders/easybuild-framework/issues/1407>.
+!!! warning
+    Use of `.yeb` easyconfigs is deprecated and [will be removed in EasyBuild v5.0][yeb].
 
 Useful links: