
.. include:: /Includes.rst.txt

===================
Documenting Changes
===================

Motivation and goals
====================

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Spreading information about important Core changes has been a problematic issue
ever since. With the switch to the new release cycle with version 7 of the
TYPO3 CMS Core this situation should be improved.

A dedicated changelog of important changes is established to inform users,
developers and other Core related teams or projects:

-   Overview for documentation team which changes trigger documentation changes.

-   Overview for Release Managers and other "Spread the word" related works on
    important changes.

-   Hints for extension developers, integrators and project developers whose
    own code areas may need adjustments on Core updates.

-   Standardized format for easy usage in scripts like a Core migration or
    release notes system.


Different changelog types
=========================

A changelog handles one of these change types:

Breaking change
    A patch moved or removed a specific part of Core functionality that may
    break extensions if they use this part. Removal of deprecated code or an
    interface change are good examples of this type.

Deprecation
    A patch deprecates a certain Core functionality for a planned removal.

Feature
    A patch adds new functionality.

Important
    Any other important message which may require manual action.

Casual bug fixes do not need changelog files, but every change that may be of
special interest for extension developers or documentation writers should
receive an entry. The changelog file must be provided as part of the patch that
introduces the change.


Location
========

New changelog files are added to the directory of the minor version that they
will be released in, for example
:file:`typo3/sysext/core/Documentation/Changelog/12.1` directory.

This way it can be easily seen which change has been introduced in which
released TYPO3 version.

In rare cases, patches worth a changelog file need to be backported to stable
LTS and / or old stable LTS versions. Those should be put into a different
directory, depending on target LTS versions. We'll explain this by example:

Suppose Core is currently developing v12, a first 12.0 has been released, so
the Git branch `main` will become version 12.1.0 with the
next sprint release. So new Changelog entries will be saved in folder
:file:`typo3/sysext/core/Documentation/Changelog/12.0`.
The stable LTS version is currently 11.5.3, so the Git branch `11.5` will
become version 11.5.4 with the next stable LTS patch level release.
The old stable LTS version is currently 10.4.21, so the Git branch `10.4`
will become version 10.4.22 with next old stable LTS
patch level release.

Example scenarios:

*   **A patch is only added to main:** Put the :file:`.rst` file into the
    :file:`typo3/sysext/core/Documentation/Changelog/12.1`
    directory in the `main` branch. The Core team will re-review files in
    this directory shortly before the 12.1 release.

*   **A patch is not only added to main, but also backported to v11:**
    Put the :file:`.rst` file into the
    :file:`typo3/sysext/core/Documentation/Changelog/11.5.x` directory in
    the `main` branch.
    The backport to `11.5` branch includes the changelog file into
    :file:`11.5.x` directory, too.
    Users upgrading to latest patch level release of 11.5 will then see the
    new file in the :file:`11.5.x` directory.

*   **A patch is not only added to main, but backported to v11 and v10:**
    Put the :file:`.rst` file into
    :file:`typo3/sysext/core/Documentation/Changelog/11.5.x` and a duplicate into
    :file:`typo3/sysext/core/Documentation/Changelog/10.4.x` directories in the
    `main` branch.
    The backport to the `11.5` branch has the two identical files in both
    directories, too.
    The `10.4 branch backport contains only the
    :file:`typo3/sysext/core/Documentation/Changelog/10.4.x`, the `11.5.x`
    directory does not exist in the version 10 branch.

    Users upgrading to latest 10.4 patch level or the latest 11.5 patch level
    will then see the new file in :file:`11.5.x` directory or in :file:`10.4.x`
    directory, respectively.

The main goal of this approach is to have a consistent state of changelog file
across branches. Changelog files are added to the oldest release branch where
a change has been backported to, thus basically the first TYPO3 version where
a change is visible. Changelog files from older releases are never deleted in
younger branches.

They are still rendered in
:guilabel:`Admin Tools > Upgrade > View Upgrade Documentation` and are
connected to the extension scanner at
:guilabel:`Admin Tools > Upgrade > View Upgrade Documentation`. In our example
above, the `main` branch contains all changelog files for TYPO3 v12, v11 and
v10, the branch `11.5` contains all files for TYPO3 v11 and v10, and the branch
`10.4` contains all v10 files.

Furthermore, documentation files from older releases should be identical in
all branches. If a patch improves some documentation file from a v10 directory,
this change should be put into all branches: `main`, `11.5`
and `10.4` for consistency. The Core Team will check for differences of files
between branches occasionally and will align them in case they diverged.


Filename convention
===================

.. code-block:: none

    <type>-<forgeIssueNumber>-<UpperCamelCaseDescription>.rst

For example

.. code-block:: none

    Deprecation-95800-GeneratingPublicURLForPrivateAssetFiles.rst


File content
============

Like other documentation, changelog files are done in ReST, see
:ref:`h2document:rest-cheat-sheet` for more details.

-   All types contain a "Description" section that should give a short summary
    on which Core part was affected by the change.

-   All types contain an "Impact" section that describes the possible impact of
    a change. An example is "Frontend output may change", "Configuration of xy
    is easier" or "Backend will throw a fatal error".

-   Types "Deprecation" and "Breaking" contain an "Affected installations"
    section that describes when and if a TYPO3 instance is affected by a change.
    Example: "Extension xy is in use" or "TypoScript functionality xy is used"
    or "System is based on PHP 8.1".

-   Types "Deprecation" and "Breaking" contain a "Migration" section to
    describe best practices on how to cope with a specific change.

-   All types contain a list of tags, see below.


Tagging
=======

To provide the possibility to filter ReST files by topics, it is mandatory to
equip every :file:`.rst` file with at least two tags. As a rule of thumb a file
should have no more than five tags. Please limit yourself to the list
provided below. If you are in dearly need to introduce a new tag, you must
also add it to the list (and explain it) in this file as a reference
for everyone.

The tag list should be located at the end of a ReST file prefixed with the
index keyword, example: `.. index:: Backend, JavaScript, NotScanned`.

List of all possible tags:

TypoScript
    Changes that imply or introduce alterations to some TypoScript settings or
    modify the behavior of TypoScript itself. Frontend TypoScript only.

TSconfig
    Changes or modifications on the PageTS or UserTS or the behavior of this
    field.

TCA
    Every change related to TCA.

FlexForm
    Changes affecting FlexForm functionality.

LocalConfiguration
    Changes that affect the :file:`system/settings.php` or the subordinated
    :file:`system/additional.php`.

Fluid
    Changes that alter behavior of Fluid like introducing new tags or
    modifying already established ones.

FAL
    Changes to File Abstraction Layer.

Database
    Changes that modify behavior of the database abstraction or introduces or removes new fields.

JavaScript
    Modifying or introducing JavaScript.

PHP-API
    Implementations of mandatory changes of the PHP-API.

Frontend
    Changes that will affect the behavior or rendering of the TYPO3 Frontend.

Backend
    Changes that will affect the behavior or rendering of the TYPO3 Backend.

CLI
    Changes affecting CLI functionality.

RTE
    Changes to RTE functionality.

ext:xyz
    Changes on extension xyz. Please refer to this tag only when changing system extensions.

Furthermore, exactly one of the following tags **must** be added for all
`Deprecation` and `Breaking` ReST files since TYPO3 v9 and above:

NotScanned
    If this ReST file is not covered by the extension scanner at all.

PartiallyScanned
    If some parts of the deprecated / removed functionality can be found by
    the extension scanner.

FullyScanned
    If usages of all deprecated / removed functionality this ReST file is
    about can be found by the extension scanner. This tag is used by
    the extension scanner to mark a ReST file as "You are not affected by this
    in your codebase" if it does not find a match in extensions.
