Files
haskell.nix/test
Hamish Mackenzie 0366537651 Use new cleanSourceWith to filter component source (#209)
When trying to build haskell packages from local source using nix (
source code you have used `git clone` to retrieve and have modified)
it is often annoying that small changes can trigger a lot of components
to be built unnecessarily.  For instance if you change the code for
a test in a package it will often trigger builds of the library and
all its dependencies.

To avoid this problem we could manually set up `cleanSourceWith` calls
in nix to filter out files that are not need, but to do this every
component would be difficult and error prone.

This change automates this process using the information in the
packages `.cabal` file to filter the source of each component
automatically  when using `callCabalPlanToNix` (we should be able to
add it to `callStackToNix` too).

## How does it work?

* A new version on `cleanSourceWith` is used that adds a `subDir`
  argument.  It allows descending into a subdirectory to compose with
  cleaning the source.

* A new `--full` argument is passed to `plan-to-nix` by
  `callCabalPlanToNix` telling it to output extra information about
  the cabal packages in the plan (directories and filenames).

* `callCabalProjectToNix` uses the new `subDir` argument of
  `cleanSourceWith` when setting the packageSrc.

* `comp-builder.nix` and `setup-builder.nix` use a new
  `cleanCabalComponent` function to further clean the packageSrc
  using the new information in the `package` and `component`.

## hpack wildcards
`package.yaml` files can include wild cards and these are not handled
yet (they do not map to anything in the `.cabal` file and so are lost).
They will need to be added manually to the appropriate field
(eg. `packages.xyz.package.dataFiles`)

If your hpack file does not contain wildcards or if you are willing to
add the wildcards entries manually in nix it is still useful to
enable cleaning on hpack.

For example:

```
packages.ghc-toolkit.package.cleanHpack = true;
packages.ghc-toolkit.components.library.extraSrcFiles = [
  "genapply/**/**"
  "boot-libs/**/**"
  "ghc-libdir/**/**"
  ];
```
2019-08-26 12:27:47 +02:00
..

Haskell infrastructure test cases

To build the test cases, run from the test directory:

nix-build --no-out-link default.nix

To run all tests (includes impure tests), use the script:

./tests.sh

Generated code

If you change the test Cabal files or need to regenerate the code with nix-tools, then see regen.nix. Run it like this:

$(nix-build --no-out-link regen.nix)