feat(@angular/cli): add trailing slash to deployUrl when missing

[tomastrajan]

Closes #7295

[filipesilva]

@clydin can you review please?

[clydin]

As currently implemented, the deploy URL option mimics the behavior of webpack's public path option which simply prepends the value provided to resource requests. So technically this PR would be a breaking change. However, I'm not sure anyone is currently using the option to prepend directly to the filename of the resource (as opposed to the common case of adjusting the path).

Also of note, the CLI's base href option also would typically require the user to use a trailing slash. According to the specification, the trailing slash is actually significant to the meaning of the base href value (i.e., /base/ and /base have different behavior within a web browser).

[tomastrajan]

@clydin I had similar worries and asked Webpack guys directly and got response that it is always safe to append trailing slash when missing on publicPath. Then again the context in the question was lacking so it's possible that answer didn't account for all use cases.

EDIT: what I remember from debugging original issue is that it all boils down to

/******/ 	// __webpack_public_path__
/******/ 	__webpack_require__.p = "/something";

in the inline.bundle.js.

This gets correctly resolved (slash is added automatically) for scripts like in index.html

<script type="text/javascript" src="/something/inline.bundle.js">

but not for stuff referenced from sass like in the original issue.

[clydin]

This is something that webpack should probably fix directly but changing it here as well shouldn't cause a problem.

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}