nunnatsa / ginkgolinter / 6811556342

84%

main: 88%

Pull #118

github

New rule(s): Wrong Usage of the `MatchError` gomega Matcher

The `MatchError` gomega matcher asserts an error value (and if it's not nil).

There are four valid formats for using this Matcher:
* error value; e.g. `Expect(err).To(MatchError(anotherErr))`
* string, to be equal to the output of the `Error()` method; e.g. `Expect(err).To(MatchError("Not Found"))`
* A gomega matcher that asserts strings; e.g. `Expect(err).To(MatchError(ContainSubstring("Found")))`
* [from v0.29.0] a function that receive a single error parameter and returns a single boolean value.
  In this format, an additional single string parameter, with the function description, is also required; e.g.
  `Expect(err).To(MatchError(isNotFound, "is the error is a not found error"))`

These four format are checked on runtime, but sometimes it's too late. ginkgolinter performs a static analysis and so it
will find these issues on build time.

ginkgolinter checks the following:
* Is the first parameter is one of the four options above.
* That there are no additional parameters passed to the matcher; e.g.
  `MatchError(isNotFoundFunc, "a valid description" , "not used string")`. In this case, the matcher won't fail on run
  time, but the additional parameters are not in use and ignored.
* If the first parameter is a function with the format of `func(error)bool`, ginkgolinter makes sure that the second
  parameter exists and its type is string.

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