revise landing page with overview of changes in EasyBuild v5.0

Author: boegel

docs/easybuild-v5/backwards-incompatible-changes.md

@@ -1,17 +1,17 @@
 # Changes in default configuration in EasyBuild v5.0
 
-*(for a full overview of changes in EasyBuild v5.0, see [here](overview-of-changes.md))*
+*(for a full overview of changes in EasyBuild v5.0, see [here](index.md))*
 
-Various changes in default configuration included in EasyBuild v5.0, including:
+The default value for several EasyBuild configuration settings has been changed in EasyBuild v5.0:
 
-* [Enable RPATH linking by default][rpath]
-* [Enable `--trace` by default][trace]
+- [RPATH linking is enabled by default (`--rpath`)](rpath)
+- [Trace output is enabled by default (`--trace`)](trace)
 
 ---
 
 ## Enable RPATH linking by default {: #rpath }
 
-[RPATH linking][rpath_support] is enabled by default in EasyBuild v5.0 (see [easybuild-framework PR #4448](https://github.com/easybuilders/easybuild-framework/pull/4448)).
+[RPATH linking][rpath_support] is enabled by default in EasyBuild v5.0.
 
 The benefits for enabling RPATH are explained in [Why RPATH?][rpath_support_why].
 
@@ -20,31 +20,34 @@ will continue to be appended by the environment module files EasyBuild generates
 unless it is configured to filter these variables (via `--filter-env-vars`,
 see also [Relation to `$LD_LIBRARY_PATH`][rpath_support_LD_LIBRARY_PATH]).
 
+The RPATH part of the EasyBuild sanity check has been relaxed (by default,
+to allow for installing software that uses RPATH linking on top of existing software installations that do not use RPATH.
+The RPATH sanity check can be made strict again via the `strict-rpath-sanity-check` EasyBuild configuration setting.
+
 To disable RPATH linking, either:
 
-* Use the `--disable-rpath` command line option;
-* Set the `$EASYBUILD_DISABLE_RPATH` environment variable;
-* Disable RPATH linking in an EasyBuild [configuration file](../configuration.md#configuration_file):
+- Use the `--disable-rpath` command line option;
+- Set the `$EASYBUILD_DISABLE_RPATH` environment variable;
+- Disable RPATH linking in an EasyBuild [configuration file](../configuration.md#configuration_file):
 
     ``` ini
     [override]
     rpath=0
     ```
 
-
 ---
 
 ## Enable `--trace` by default {: #trace }
 
-The [`--trace` option](../tracing-progress.md) is enabled by default (see [easybuild-framework PR #4250](https://github.com/easybuilders/easybuild-framework/pull/4250)).
+The [`--trace` option](../tracing-progress.md) is enabled by default.
 
 This makes the output produced by the `eb` command more informative, by providing more information about what's going on in the background.
 
 To disable trace output, either:
 
-* Use the `--disable-trace` command line option;
-* Set the `$EASYBUILD_DISABLE_TRACE` environment variable;
-* Disable trace mode in a [configuration file](../configuration.md#configuration_file):
+- Use the `--disable-trace` command line option;
+- Set the `$EASYBUILD_DISABLE_TRACE` environment variable;
+- Disable trace mode in a [configuration file](../configuration.md#configuration_file):
 
     ``` ini
     [override]

docs/easybuild-v5/changes-in-default-configuration.md

@@ -1,19 +1,20 @@
 # Deprecated functionality in EasyBuild v5.0
 
-*(for a full overview of changes in EasyBuild v5.0, see [here](overview-of-changes.md))*
+*(for a full overview of changes in EasyBuild v5.0, see [here](index.md))*
 
 Some functionality is being deprecated in EasyBuild v5.0, and will no longer be supported in EasyBuild v6.0:
 
-* [`run_cmd` and `run_cmd_qa` functions][run_cmd]
-* [`easybuild.tools.py2vs3` module][py2vs3]
+- [`run_cmd` and `run_cmd_qa` functions][run_cmd]
+- [`easybuild.tools.py2vs3` module][py2vs3]
 
 If you trigger any deprecated functionality when using EasyBuild v5.0, a warning message will be printed.
 
 ---
 
 ## `run_cmd` and `run_cmd_qa` functions {: #run_cmd }
 
-The `run_cmd` and `run_cmd_qa` functions will be deprecated.
+The `run_cmd` and `run_cmd_qa` functions have been deprecated,
+and are scheduled to be removed in EasyBuild v6.0.
 
 You should migrate to the new [`run_shell_cmd`](run_shell_cmd.md) function instead.
 
@@ -22,8 +23,6 @@ You should migrate to the new [`run_shell_cmd`](run_shell_cmd.md) function inste
 
 ## `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 |

docs/easybuild-v5/deprecated-functionality.md

@@ -1,19 +1,20 @@
 # Enhancements in EasyBuild v5.0
 
-*(for a full overview of changes in EasyBuild v5.0, see [here](overview-of-changes.md))*
+*(for a full overview of changes in EasyBuild v5.0, see [here](index.md))*
 
 Various significant enhancements are included in EasyBuild v5.0, including:
 
-* [`run_shell_cmd` function][run_shell_cmd]
-* [Granular exit codes][granular_exit_codes]
-* [Reproducible tarballs][reproducible_tarballs]
+- [`run_shell_cmd` function][run_shell_cmd]
+- [Granular exit codes][granular_exit_codes]
+- [Reproducible tarballs][reproducible_tarballs]
 
 ---
 
 ## `run_shell_cmd` function { : #run_shell_cmd }
 
 See dedicated page on the new [`run_shell_cmd` function](run_shell_cmd.md).
 
+
 ## Granular exit codes { : #granular_exit_codes }
 
 EasyBuild v5 now uses a range of ~50 exit codes instead of just 0 for normal
@@ -27,6 +28,7 @@ EasyBuild will always return its own exit codes on termination. Other exit
 codes from external processes executed through `run_shell_cmd` or HTTP response
 status codes are reported in the corresponding logs.
 
+
 ## Reproducible tarballs { : #reproducible_tarballs}
 
 EasyBuild can now generate reproducible tarballs of sources cloned from Git

docs/easybuild-v5/enhancements.md

@@ -1,13 +1,91 @@
 # EasyBuild v5.0
 
+A high-level overview of changes in EasyBuild version 5.0 is listed below.
+
+Click on a particular item for more information.
+
+!!! warning "EasyBuild version 5.0.0 is not released yet"
+
+    EasyBuild v5.0.0 is still under active development via the `5.0.x` branches in the EasyBuild GitHub repositories.
+
+    Shortly before the release of EasyBuild v5.0.0, the `5.0.x` branches will be collapsed in the corresponding
+    `develop` branches, and the `5.0.x` branches will then only be used as a staging area for additional EasyBuild
+    v5.0.x releases.
+
+    The overview below is known to be incomplete, and will be gradually completed as we approach
+    the release of EasyBuild v5.0.0.
+
+---
+
+## Breaking changes {: #breaking-changes }
+
+EasyBuild v5.0 includes a number of backwards-incompatible changes:
+
+- [Python 3.6+ is required to run EasyBuild v5.0.0](python36-required.md)
+
+See also the [overview of removed functionality][removed-functionality] below.
+
+
+---
+
+## Changes in default configuration
+
+The default value for several EasyBuild configuration settings has been changed in EasyBuild v5.0:
+
+- [RPATH linking is enabled by default (`--rpath`)](changes-in-default-configuration.md#rpath)
+- [Trace output is enabled by default (`--trace`)](changes-in-default-configuration.md#trace)
+
+
+---
+
+## Enhancements
+
+Various significant enhancements are included in EasyBuild v5.0, including:
+
+- [`run_shell_cmd` function](run_shell_cmd.md)
+- [Granular exit codes](enhancements.md#granular_exit_codes)
+- [Reproducible tarballs](enhancements.md#reproducible_tarballs)
+ 
+
+---
+
+## Removed functionality {: #removed-functionality }
+
+Functionality that was deprecated a while ago has been removed:
+
+- [EasyBuild bootstrap script is removed](removed-functionality.md#bootstrap_script) 
+- [Experimental support for `.yeb` easyconfig format is removed](removed-functionality.md#yeb)
+
+
+---
+
+## Deprecated functionality {: #deprecated-functionality }
+
+Some functionality is being deprecated in EasyBuild v5.0, and will no longer be supported in EasyBuild v6.0:
+
+- [`run_cmd` and `run_cmd_qa` functions](deprecated-functionality.md#run_cmd)
+- [`easybuild.tools.py2vs3` module](deprecated-functionality.md#py2vs3)
+
+
+---
+
+## Other changes
+
+*(coming soon)*
+
+
+---
+
+## FAQ
+
+*(coming soon)*
+
+
+---
+
+## Other links
 
 - [Beta releases and release candidates](release-candidates.md)
-- [Overview of changes](overview-of-changes.md)
-    - [Backwards-incompatible changes](backwards-incompatible-changes.md)
-    - [Changes in default configuration](changes-in-default-configuration.md)
-    - [Enhancements](enhancements.md)
-        - [`run_shell_cmd` function](run_shell_cmd.md)
-    - [Deprecated functionality](deprecated-functionality.md)
-    - [Policies](policies.md)
-- [GitHub Project board](https://github.com/orgs/easybuilders/projects/18)
+- [GitHub Project board for EasyBuild v5.0](https://github.com/orgs/easybuilders/projects/18)
 - [Talk on EasyBuild 5.0 at EasyBuild User Meeting 2023](https://easybuild.io/eum23/#easybuild5)
+- [Talk on EasyBuild 5.0 at EasyBuild User Meeting 2024](https://easybuild.io/eum24/#eb5)

docs/easybuild-v5/index.md

@@ -0,0 +1,28 @@
+# Python 3.6+ is required to run EasyBuild v5.0.0
+
+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 [here](deprecated-functionality.md#py2vs3)).

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

@@ -0,0 +1,25 @@
+# Removed functionality in EasyBuild v5.0
+
+*(for a full overview of changes in EasyBuild v5.0, see [here](index.md))*
+
+Functionality that was deprecated a while ago has been removed:
+
+- [EasyBuild bootstrap script is removed][bootstrap_script]
+- [Experimental support for `.yeb` easyconfig format is removed][yeb]
+
+---
+
+## 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.md) for the suggested methods for installing EasyBuild.
+
+---
+
+## Experimental support for `.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 at all.

docs/easybuild-v5/policies.md

@@ -1,6 +1,6 @@
 # `run_shell_cmd` function
 
-*(for a full overview of changes in EasyBuild v5.0, see [here](overview-of-changes.md))*
+*(for a full overview of changes in EasyBuild v5.0, see [here](index.md))*
 
 In EasyBuild v5.0, a new function named `run_shell_cmd` is introduced to run shell commands.