Fix: prevent space-before-function-paren from checking type annotations

[not-an-aardvark]

What is the purpose of this pull request? (put an "X" next to item)

[x] Bug fix

Tell us about your environment

• ESLint Version: master
• Node Version: 7.7.4
• npm Version: 4.1.2

What parser (default, Babel-ESLint, etc.) are you using?

babel-eslint

Please show your full configuration:

parser: babel-eslint
rules:
  space-before-function-paren: error

What did you do? Please include the actual source code causing the issue.

type TransformFunction = (el: ASTElement, code: string) => string;

What did you expect to happen?

I expected ESLint to not crash.

What actually happened? Please include the actual, raw output from ESLint.

ESLint crashed.

TypeError: Cannot read property 'range' of null
    at TokenStore.getTokenBefore (/path/to/eslint-canary/.downloaded-projects/vue/node_modules/eslint/lib/token-store/index.js:318:17)
    at EventEmitter.:function (/path/to/eslint-canary/.downloaded-projects/vue/node_modules/eslint/lib/rules/space-before-function-paren.js:116:46)
    at emitOne (events.js:96:13)
    at EventEmitter.emit (events.js:191:7)
    at NodeEventGenerator.applySelector (/path/to/eslint-canary/.downloaded-projects/vue/node_modules/eslint/lib/util/node-event-generator.js:265:26)
    at NodeEventGenerator.applySelectors (/path/to/eslint-canary/.downloaded-projects/vue/node_modules/eslint/lib/util/node-event-generator.js:292:22)
    at NodeEventGenerator.enterNode (/path/to/eslint-canary/.downloaded-projects/vue/node_modules/eslint/lib/util/node-event-generator.js:308:14)
    at CodePathAnalyzer.enterNode (/path/to/eslint-canary/.downloaded-projects/vue/node_modules/eslint/lib/code-path-analysis/code-path-analyzer.js:602:23)
    at CommentEventGenerator.enterNode (/path/to/eslint-canary/.downloaded-projects/vue/node_modules/eslint/lib/util/comment-event-generator.js:98:23)
    at Traverser.enter (/path/to/eslint-canary/.downloaded-projects/vue/node_modules/eslint/lib/eslint.js:929:36)

This was working in 3.18.0, but it broke due to 9b509ce.

What changes did you make? (Give an overview)

Previously, the space-before-function-paren rule's listener would be triggered for custom nodes such as FunctionTypeAnnotation, and would throw an error. This broke the regression build. This commit updates the rule to only listen for known function nodes.

Is there anything you'd like reviewers to focus on?

Nothing in particular

[mention-bot]

@not-an-aardvark, thanks for your PR! By analyzing the history of the files in this pull request, we identified @btmills, @nzakas and @alberto to be potential reviewers.

[eslintbot]

LGTM

[ilyavolodin]

I think at some point we need to figure out a better way to test those changes. Those fixtures are huge.

[not-an-aardvark]

We could add babel-eslint as a devDependency for testing and have it handle the parsing on its own.

[vitorbal]

I'm not sure, but would it make sense to name the folder tests/fixtures/parsers/babel/ instead? Or maybe we could clean up/re-organize the fixtures/parsers/ folder in a separate PR. I think it's a bit confusing now where to put parser fixtures.. related: https://github.com/eslint/eslint/pull/8297/files#diff-824f19921586246afb6f381021c34222

[not-an-aardvark]

Good idea, I moved the fixture. I agree with reorganizing the folder in a separate PR.

[eslintbot]

LGTM