Fingerprints should be generated after autoprefixing files

[mirague]

It would seem the generated fingerprint on .css files is generated -before- the file's contents are autoprefixed. See this diff, comparing the original vendor.css file (without autoprefixing) to the one post autoprefixing:
https://www.diffchecker.com/xk5ell28

Both of them have the following fingerprint:

<link rel="stylesheet" href="/assets/vendor-71a8f7f0ec9ee74bd7700d99a5f0b69d.css" integrity="sha256-Wfg3oOX5yWiadWxDW9FY1hyYG5JAGkQ4UUeaf7bTXmg= sha512-ykM/yDR0Yy/sRRHm2hNUUQtV/MgRLeX1RYc3wNVLRpIB47kbD5C4goWlbBK9077Y7hTM3XGcNtpBevekWsoHoQ==">

This is an issue when:

• the file is cached as vendor-71a8f7f0ec9ee74bd7700d99a5f0b69d.css (without autoprefixing)
• the contents change due to autoprefixing (diff), the filename remains the same.
• the generated integrity hashes -do- change and suddenly the user's cached version conflicts and is not loaded:

Versions
Ember: 2.15.1
broccoli-asset-rev:
ember-cli-autoprefixer: 0.8.0

[mirague]

The underlying cause may be similar to that of ember-cli/broccoli-asset-rev#118, which was addressed by introducing a two-stage pipeline approach: ember-cli/broccoli-asset-rev#121

[cbrevdev]

Oh nice find! ember-cli-autoprefixer is indeed being run after the fingerprinting stage.

DEBUG="*:Fingerprint,*:AutoprefixerFilter,*:SRIHashAssets" ember build --prod

Shows:

broccoli-filter:Fingerprint
broccoli-persistent-filter:AutoprefixerFilter
broccoli-caching-writer:SRIHashAssets

with mismatched asset fingerprint:

MD5 (dist/assets/vendor-eaf3a09c2cb3eef1a98fd76408256234.css) = 25f52e8d963d263cc305c82b2ba54368

We can influence the order by modifying package.json to indicate that autoprefix must occur before broccoli-asset-rev:

"ember-addon": {
    "configPath": "tests/dummy/config",
    "before": "broccoli-asset-rev"
},

resulting in an adjusted build order:

broccoli-persistent-filter:AutoprefixerFilter
broccoli-filter:Fingerprint
broccoli-caching-writer:SRIHashAssets

and corrected asset fingerprint:

MD5 (dist/assets/vendor-25f52e8d963d263cc305c82b2ba54368.css) = 25f52e8d963d263cc305c82b2ba54368

I'll put together a PR.

[mirague]

Hey @cbrevdev, thanks for the quick reply and PR! I had no idea about the existence of the "before" mechanic - I'm happy you did!

[kimroen]

Thank you very much for this, both of you. This has been fixed in #39 and released as version 0.8.1 now! 🎉