file-format-changelog.rst

.. _spec-history:

==================================================
Package Description Format Specification History
==================================================

:ref:`pkg-desc` need to specify the version of the
specification they need to be interpreted in via the
:pkg-field:`cabal-version` declaration. The following list describes
changes that occurred in each version of the cabal specification
relative to the respective preceding *published* version.

.. note::

The sequence of specification version numbers is *not*
contiguous because it's synchronised with the version of the
``Cabal`` library. As a consequence, only *even* versions are
considered proper published versions of the specification as *odd*
versions of the ``Cabal`` library denote unreleased development
branches which have no stability guarantee.

``cabal-version: 3.12``
-----------------------

* License fields use identifiers from SPDX License List version
``3.23 2024-02-08``.

``cabal-version: 3.8``
----------------------

* Added field ``code-generators`` to :pkg-section:`test-suite` stanzas. This
enumerates executabes (possibly brought into scope by :pkg-field:`build-tool-depends`) that are run after all other
preprocessors. These executables are invoked with a target dir for
output, a sequence of all source directories with source files of
local lib components that the given test stanza depends on, and
following a double dash, all options cabal would pass to ghc for a
build. They are expected to output a newline-separated list of
generated modules which have been written to the targetdir. This can
be used for driving doctests and other discover-style tests generated
from source code.

* Added fields :pkg-field:`extra-libraries-static` and
:pkg-field:`extra-lib-dirs-static` to allow Haskell libraries to remember
linker flags needed for fully static linking of system libraries into
executables.
The existing field :pkg-field:`pkgconfig-depends` can used to append
the relevant output of ``pkg-config --libs --static`` to these new fields
automatically.
When :pkg-field:`extra-libraries-static` is not given, it defaults to
:pkg-field:`extra-libraries`.
When :pkg-field:`extra-lib-dirs-static` is not given, it defaults to
:pkg-field:`extra-lib-dirs`.

* Wildcard matching has been slightly expanded. Matches are now
allowed of the form ``foo/**/literalFile``. Prior, double-star
wildcards required the trailing filename itself be a wildcard.

* Allow the omission of the `type` field in `test-suite` and `benchmark` stanzas
when the type can be inferred by the presence of `main-is` or `test-module`.

* License fields use identifiers from SPDX License List version
``3.16 2022-02-06``

``cabal-version: 3.6``
----------------------

* License fields use identifiers from SPDX License List version
``3.10 2020-08-03``

* Add :pkg-field:`hsc2hs-options`

``cabal-version: 3.4``
----------------------

* License fields use identifiers from SPDX License List version
``3.9 2020-05-15``

* Dependencies to sublibraries must be specified explicitly,
even for current package.
For example: ``build-depends: mypackage:my-sublib``
This way you can have a sublibrary with the same
name as some external dependency.

* Remove ``-any`` and ``-none`` syntax for version ranges
Use ``>=0`` and ``<0`` respectively.

* :pkg-field:`default-language` is optional.
The Default value is to use the compiler's default language.

* :pkg-field:`mixins` field allow specifying a sublibrary.

``cabal-version: 3.0``
----------------------

* New :pkg-field:`library:visibility` for exposing sublibraries.

* New ``pkg:lib`` and ``pkg:{lib1,lib2}`` syntax in :pkg-field:`build-depends`
for depending on public sublibraries from other packages.

* Added the :pkg-field:`extra-dynamic-library-flavours` field to specify non-trivial
variants of dynamic flavours. It is :pkg-field:`extra-library-flavours` but for
shared libraries. Mainly useful for GHC's RTS library.

* Free text fields (e.g. :pkg-field:`description`) preserve empty lines
and indentation. In other words, you don't need to add dots for blank lines.

* License fields use identifiers from SPDX License List version
``3.6 2019-07-10``

* Remove deprecated ``hs-source-dir``, :pkg-field:`extensions` and
:pkg-field:`build-tools` fields.

* Common stanzas are now allowed also in the beginning of conditional
sections. In other words, the following is valid

::

library
import deps

if flag(foo)
import foo-deps

* Allow redundant leading or trailing commas in package fields with
optional commas, such as :pkg-field:`library:exposed-modules`

* Require fields with optional commas to consistently omit or place
commas between elements.

* Changed the behavior of :pkg-field:`extra-bundled-libraries` field. The naming convention
of dynamic library files (e.g. generated by a custom build script) has
changed. For library names prefixed with "C", the dynamic library file
name(s) must be of the form `lib.*`
instead of the old `libC-ghc.`

* New set-notation syntax for ``==`` and ``^>=`` operators, see
:pkg-field:`build-depends` field documentation for examples.

* Allow more whitespace in :pkg-field:`mixins` field

* Wildcards are disallowed in :pkg-field:`pkgconfig-depends`,
Yet the pkgconfig format is relaxed to accept e.g. versions like ``1.1.0h``.

* New :pkg-field:`autogen-includes` for specifying :pkg-field:`install-includes`
which are autogenerated (e.g. by a ``configure`` script).

* New :pkg-field:`asm-sources` and :pkg-field:`asm-options` fields
added for supporting bundled foreign routines implemented in
assembler.

* New :pkg-field:`cmm-sources` and :pkg-field:`cmm-options` fields
added for supporting bundled foreign primops implemented in
C--.

``cabal-version: 2.4``
----------------------

* Wildcard matching has been expanded. All previous wildcard
expressions are still valid; some will match strictly more files
than before. Specifically:

* Double-star (``**``) wildcards are now accepted for recursive
matching immediately before the final slash; they must be followed
by a filename wildcard (e.g., ``foo/**/*.html`` is valid;
``foo/**/bar/*.html`` and ``foo/**/**/*.html``,
``foo/**/bar.html`` are all invalid). As ``**`` was an error in
globs before, this does not affect any existing ``.cabal`` files
that previously worked.
(Caveat: Double-star wildcards in :pkg-field:`data-files` directories,
e.g. ``data-files: data/**/*.csv``,
`are only supported correctly from Cabal 3.0 `_.)

* Wildcards now match when the pattern's extensions form a suffix of
the candidate file's extension, rather than requiring strict
equality (e.g., previously ``*.html`` did not match
``foo.en.html``, but now it does).

* License fields use identifiers from SPDX License List version
``3.2 2018-07-10``

``cabal-version: 2.2``
----------------------

* New :pkg-section:`common` stanzas and :pkg-field:`import`
pseudo-field added.

* New :pkg-field:`library:virtual-modules` field added.

* New :pkg-field:`cxx-sources` and :pkg-field:`cxx-options` fields
added for supporting bundled foreign routines implemented in C++.

* New :pkg-field:`extra-bundled-libraries` field for specifying
additional custom library objects to be installed.

* Extended ``if`` control structure with support for ``elif`` keyword.

* Changed default rules of :pkg-field:`build-type` field to infer
"build-type:" for "Simple"/"Custom" automatically.

* :pkg-field:`license` field syntax changed to require SPDX
expression syntax (using SPDX license list version ``3.0 2017-12-28``).

* Allow redundant leading or trailing commas in package fields (which
require commas) such as :pkg-field:`build-depends`.

``cabal-version: 2.0``
----------------------

* New :pkg-field:`library:signatures` and :pkg-field:`mixins` fields
added for supporting :ref:`Backpack`.

* New :pkg-field:`build-tool-depends` field added for adding
build-time dependencies of executable components.

* New :pkg-field:`custom-setup:autogen-modules` field added for declaring modules
which are generated at build time.

* Support for new PVP_ caret-style version operator (``^>=``) added to
:pkg-field:`build-depends`.

* Add support for new :pkg-section:`foreign-library` stanza.

* Add support for :ref:`sublibrary stanzas `.

* New CPP Macro ``CURRENT_PACKAGE_VERSION``.

``cabal-version: 1.24``
-----------------------

* New :pkg-section:`custom-setup` stanza and
:pkg-field:`custom-setup:setup-depends` field added for specifying dependencies
of custom ``Setup.hs`` scripts.

* CPP Macros ``VERSION_$pkgname`` and ``MIN_VERSION_$pkgname`` are now
also generated for the current package.

* New CPP Macros ``CURRENT_COMPONENT_ID`` and ``CURRENT_PACKAGE_KEY``.

* New :pkg-field:`extra-framework-dirs` field added for specifying
extra locations to find OS X frameworks.

``cabal-version: 1.22``
-----------------------

* New :pkg-field:`library:reexported-modules` field.

* Support for ``-none`` version constraint added to
:pkg-field:`build-depends`.

* New :pkg-field:`license` type ``ISC`` added.

``cabal-version: 1.20``
-----------------------

* Add support for new :pkg-field:`license-files` field for declaring
multiple license documents.

* New CPP Macro ``MIN_TOOL_VERSION_$buildtool``.

* New :pkg-field:`license` types ``BSD2`` and ``MPL-2.0`` added.

``cabal-version: 1.18``
-----------------------

* Add support for new :pkg-field:`extra-doc-files` field for
specifying extra file assets referenced by the Haddock
documentation.

* New :pkg-field:`license` type ``AGPL`` and ``AGPL-3`` added.

* Add support for specifying a C/C++/obj-C source file in
:pkg-field:`executable:main-is` field.

* Add ``getSysconfDir`` operation to ``Paths_`` API.

``cabal-version: 1.16``
-----------------------

.. todo::

this needs to be researched; there were only few changes between
1.12 and 1.18;

``cabal-version: 1.12``
-----------------------

* Change syntax of :pkg-field:`cabal-version` to support the new recommended
``cabal-version: x.y`` style

.. include:: references.inc