Nim/contributing.md

The git stuff

Guide by github, scroll down a bit

Deprecation

Backward compatibility is important, so if you are renaming a proc or a type, you can use

{.deprecated [oldName: new_name].}

Or you can simply use

proc oldProc() {.deprecated.}

to mark a symbol as deprecated. Works for procs/types/vars/consts, etc.

Deprecated pragma in the manual.

Writing tests

Not all the tests follow this scheme, feel free to change the ones that don't. Always leave the code cleaner than you found it.

Stdlib

If you change the stdlib (anything under lib/), put a test in the file you changed. Add the tests under an when isMainModule: condition so they only get executed when the tester is building the file. Each test should be in a separate block: statement, such that each has its own scope. Use boolean conditions and doAssert for the testing by itself, don't rely on echo statements or similar.

Sample test:

when isMainModule:
  block: # newSeqWith tests
    var seq2D = newSeqWith(4, newSeq[bool](2))
    seq2D[0][0] = true
    seq2D[1][0] = true
    seq2D[0][1] = true
    doAssert seq2D == @[@[true, true], @[true, false], @[false, false], @[false, false]]

Compiler

The tests for the compiler work differently, they are all located in tests/. Each test has its own file, which is different from the stdlib tests. At the beginning of every test is the expected side of the test. Possible keys are:

• output: The expected output, most likely via echo
• exitcode: Exit code of the test (via exit(number))
• errormsg: The expected error message
• file: The file the errormsg
• line: The line the errormsg was produced at

An example for a test:

discard """
  errormsg: "type mismatch: got (PTest)"
"""

type
  PTest = ref object

proc test(x: PTest, y: int) = nil

var buf: PTest
buf.test()

Running tests

You can run the tests with

./koch tests

which will run a good subset of tests. Some tests may fail.

Comparing tests

Because some tests fail in the current devel branch, not every fail after your change is necessarily caused by your changes.

The tester can compare two test runs. First, you need to create the reference test. You'll also need to the commit id, because that's what the tester needs to know in order to compare the two.

git checkout devel
DEVEL_COMMIT=$(git rev-parse HEAD)
./koch tests

Then switch over to your changes and run the tester again.

git checkout your-changes
./koch tests

Then you can ask the tester to create a testresults.html which will tell you if any new tests passed/failed.

./koch --print html $DEVEL_COMMIT