9. Package Description Format Specification History

Package descriptions need to specify the version of the specification they need to be interpreted in via the 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.

9.1. cabal-version: 3.8

  • Added field code-generators to test-suite stanzas. This enumerates executabes (possibly brought into scope by 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 extra-libraries-static and 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 pkgconfig-depends can used to append the relevant output of pkg-config --libs --static to these new fields automatically. When extra-libraries-static is not given, it defaults to extra-libraries. When extra-lib-dirs-static is not given, it defaults to 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

9.2. cabal-version: 3.6

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

  • Add hsc2hs-options

9.3. 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:internal-lib This way you can have an internal library with the same name as some external dependency.

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

  • default-language is optional. The Default value is to use the compiler’s default language.

  • mixins field allow specifying a sublibrary.

9.4. cabal-version: 3.0

  • New library:visibility for exposing sublibraries.

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

  • Added the extra-dynamic-library-flavours field to specify non-trivial variants of dynamic flavours. It is extra-library-flavours but for shared libraries. Mainly useful for GHC’s RTS library.

  • Free text fields (e.g. 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, extensions and 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 library:exposed-modules

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

  • Changed the behavior of 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<library-name>.<dyn-library-extension>* instead of the old libC<library-name>-ghc<ghc-flavour><ghc-version>.<dyn-library-extension>

  • New set-notation syntax for == and ^>= operators, see build-depends field documentation for examples.

  • Allow more whitespace in mixins field

  • Wildcards are disallowed in pkgconfig-depends, Yet the pkgconfig format is relaxed to accept e.g. versions like 1.1.0h.

  • New autogen-includes for specifying install-includes which are autogenerated (e.g. by a configure script).

  • New asm-sources and asm-options fields added for supporting bundled foreign routines implemented in assembler.

  • New cmm-sources and cmm-options fields added for supporting bundled foreign primops implemented in C–.

9.5. 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 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

9.6. cabal-version: 2.2

  • New common stanzas and import pseudo-field added.

  • New library:virtual-modules field added.

  • New cxx-sources and cxx-options fields added for supporting bundled foreign routines implemented in C++.

  • New 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 build-type field to infer “build-type:” for “Simple”/”Custom” automatically.

  • 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 build-depends.

9.7. cabal-version: 2.0

9.8. cabal-version: 1.24

  • New custom-setup stanza and 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 extra-framework-dirs field added for specifying extra locations to find OS X frameworks.

9.9. cabal-version: 1.22

9.10. cabal-version: 1.20

  • Add support for new license-files field for declaring multiple license documents.

  • New CPP Macro MIN_TOOL_VERSION_$buildtool.

  • New license types BSD2 and MPL-2.0 added.

9.11. cabal-version: 1.18

  • Add support for new extra-doc-files field for specifying extra file assets referenced by the Haddock documentation.

  • New license type AGPL and AGPL-3 added.

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

  • Add getSysconfDir operation to Paths_ API.

9.12. cabal-version: 1.16

Todo

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

9.13. cabal-version: 1.12

  • Change syntax of cabal-version to support the new recommended cabal-version: x.y style