Issue #5114 warn about history prop in Router-derived components

[Aprillion]

Adding a warning as suggested in issue #5114.

[pshrmn]

This should just use the warning package. You'll need to install it for react-router-dom, but it is already installed for react-router. Basically, just change this block to:

warning(
  !this.props.history,
  ...
);

[pshrmn]

This is a minor nit, but I would prefer if there were spaces inside of the curly brackets. import { Router } and import { ... as Router }.

[Aprillion]

when I tried just https://github.com//pull/5151/commits/99d971676e7131e7832ffa727c611b161fde906b, the test failed because `console.error` was called 0 times + because there was some spill-over of 2 additional console-errors for unrelated test in `HashRouter`:

lerna ERR! execute   A <BrowserRouter>
lerna ERR! execute     × warns when passed a history prop
lerna ERR! execute       Chrome 58.0.3029 (Windows 10 0.0.0)
lerna ERR! execute     Error: Expected 0 to be 1
...
lerna ERR! execute   A <HashRouter>
lerna ERR! execute     × warns when passed a history prop
lerna ERR! execute       Chrome 58.0.3029 (Windows 10 0.0.0)
lerna ERR! execute     Error: Expected 3 to be 1

the additional 2 HashRouter warnings are following:

lerna ERR! execute   A <HashRouter>
lerna ERR! execute     × warns when passed a history prop
lerna ERR! execute       Chrome 58.0.3029 (Windows 10 0.0.0)
lerna ERR! execute     Error: Expected 'Warning: setState(...): Cannot update during an existing state transition (such as within `render` or another component\'s constructor). Render methods should be a pure function of props and state; constructor side-effects are an anti-pattern, but can be moved to `componentWillMount`.' to match /<HashRouter.*import \{Router}/

@pshrmn I have better things to do that trying to debug how to test this :(

I would be happy to add spaces in imports if you think this can be merged without warning module and/or someone can figure out the tests :)

[Aprillion]

I used wrong syntax in previous change, please disregard. warning(this.props.history, ...) instead of warning(!this.props.history, ...)

[pshrmn]

The code looks good to me now, thanks!

warning (and invariant) are always weird to use because they work when the value is falsy instead of truthy.

[timdorr]

You can fill in the ellipsis in these warnings with the actual Component name.

[Aprillion]

I thought of it as a general warning to avoid using any of the Browser/Hash/Memory/Static Router with history, do you think the ellipsis makes the message unclear?

[timdorr]

OK, cleaned up the messaging a bit. Thanks!