Development Workflow

[gdevanla]

One challenge I have had while making incremental changes to the code base was that running stack build or stack test takes a while. What is the workflow other contributors follow in these scenarios?

At the least, when I run stack test, I would like to have a way to just run specific tests or just tests within a particular scope. Currently, when I run stack test,a lot of time is spent in building libraries like criterion and 'statistics`. Is there a way to turn them off as needed.

Overall, I would like to contribute to a document (assuming this is not there already) that describes a development workflow which other contributors could use. Can someone point me to any resources or share their workflow. I can create a document by compiling those.

[Lysxia]

I also wonder about this. criterion takes a loooong time to build. However it's only used by benchmarks. Does your stack.yaml mention the benchmarks/ directory? If so, it should be okay to remove it.

If you do want to build benchmarks, there is still a hacky way to avoid rebuilding criterion, which is to rename the version of aeson you're working on so that criterion doesn't depend on it. I don't know whether there is a more principled solution.

+1 to having this documented somewhere.

[bergmark]

I usually use ghci while developing. For stack: stack ghci --stack-yaml stack-nightly.yaml --test
which doesn't include benchmarks. :r to reload and main to run the test suite. Speeds things up a lot!

The tests are run with tasty, I forget how you filter which tests to run, but it seems to be possible e.g. using --pattern.

It think CONTRIBUTING.md is a good place for this info.

Thanks in advance

[bergmark]

You can apply cmd line args inside ghci using withArgs args main

[phadej]

@bergmark also

:main --pattern Foo

[bergmark]

oh, nice!

[phadej]

Also adding historyDuplicates: IgnoreConsecutive to ~/.haskeline would reduce the :r s in your history, improves GHCi driven development experience hugely. https://github.com/judah/haskeline/wiki/UserPreferences

[gdevanla]

With the latest changes on master, I am currently seeing this error. Any tips on how to handle this would be appreciated!

$ stack ghci --stack-yaml stack-nightly.yaml --test
Using main module: 1. Package `aeson' component aeson:test:tests with main-is file: ~/fsf/aeson/tests/Tests.hs

Error: While constructing the build plan, the following exceptions were encountered:

In the dependencies for aeson-1.4.5.0(+fast):
    Diff-0.3.4 from stack configuration does not match >=0.4 && <0.5  (latest matching version is 0.4.0)
needed since aeson is a build target.

Some different approaches to resolving this:

  * Set 'allow-newer: true' in ~/.stack/config.yaml to ignore all version constraints and build anyway.

  * Recommended action: try adding the following to your extra-deps in ~/fsf/aeson/stack-nightly.yaml:

- Diff-0.4.0@sha256:b5cfbeed498f555a18774ffd549bbeff7a24bdfe5984154dcfc9f4328a3c2847,1275


Error: Plan construction failed.

[bergmark]

Ah sorry, I forgot that i updated it locally. Try this:

resolver: nightly-2019-10-14
packages:
- '.'
- attoparsec-iso8601
flags:
  aeson:
    fast: true
  attoparsec-iso8601:
    fast: true
extra-deps:
- generic-deriving-1.12.4

[gdevanla]

Thanks, that works. Shouldn't this change be on master?

[bergmark]

Indeed it should

[bergmark]

Resolved by #736