Bug: Aliased indexes failing on deploy

[eileencodes]

We recently upgraded to Rails 5 / Sprockets 4 and when I deployed had an issue with aliased indexes.

This happened on assets:precompile on our production deploy - for some reason deploys to our beta servers went fine. In fact the first deploy was fine, but a subsequent deploy of changes to CSS resulted in the error. Perhaps this is a caching issue in index_alias that was missed in b0b3c66?

The error we saw on deploy was: Sprockets::FileOutsidePaths: /u/apps/bc3/releases/20150921151240/app/assets/stylesheets/all/index.scss is no longer under a load path:

The structure we have in our js/stylesheets is

all/
all/index.scss
desktop/
desktop.scss (requires desktop/index)
desktop/index.scss
etc

To fix I had to add an all.scss file that required all/index. I think index aliasing may not be working as expected and that the error message could be clearer. Previously in sprockets 3 we didn't need to add an all.scss just to require the index file from the all folder.

cc/ @jeremy if you want to add any details.

[rafaelfranca]

Aliased Indexes have a lot of gotchas right now. See #40

[eileencodes]

Ah ok thanks @rafaelfranca 👍

[jeremy]

Added 9bffa47 to expose the underlying error: that it's actually the asset's index_alias that's an external path, not the asset.filename.

Index aliases aren't compressed/expanded like the other paths yet. They're set here and stored as an UnloadedAsset param.

cc @schneems

[schneems]

The good news is that I think I got my email working again.

I was able to repro with the code from @eileencodes which was hugely helpful, thanks!

When I grep for absolute paths in the parent app's cache directory here's what i'm seeing:

$ grep -r -i "/User" tmp/cache/
# ...
tmp/cache//sprockets-4.0/55F/731/sprockets%2Fv4.0%2Ft84v-yw0MstganJX-PvWfe8mmllTNl6ajYOTmZH2axko:

o: ActiveSupport::Cache::Entry: @valueI"app/assets/stylesheets/all/index.scss?type=text/css&pipeline=self&index_alias=/Users/richardschneeman/Documents/projects/asset_cache_repo/asset_cache_test_parent/app/assets/stylesheets/all.scss&id=b87a98c889d2e0cedea5a9052d8d199475c974d6cb6c6417b7d15c1f1ffd22ae:ET:@created_atf1443124833.627042:@expires_in0

tmp/cache//sprockets-4.0/5A4/571/sprockets%2Fv4.0%2F8YQRhcxRVbsLngWROUH0Q5ycjf0smOmUpa__v5tyTloo:

o: ActiveSupport::Cache::Entry: @valueI"app/assets/stylesheets/all/index.scss?type=text/css&pipeline=self&index_alias=/Users/richardschneeman/Documents/projects/asset_cache_repo/asset_cache_test_parent/app/assets/stylesheets/all.scss&id=4d84f7f5ee2c8d3c5a2134fee4a0d505e4d2adfe0337815e9dad45e248a590e9:ET:@created_atf1443124802.368128:@expires_in0

So it looks like the absolute path is being appended to index_alias parameter in this pseudo URL scheme that we're using:

index_alias=/Users/richardschneeman/Documents/projects/asset_cache_repo/asset_cache_test_parent/app/assets/stylesheets/all.scss

This is good news because 3.x does not have this bug since it doesn't have the index_alias feature The reason why your patch works is because...I don't know, I haven't gotten that far yet. I'm going to prioritize looking into #141 since that affects an actively released versions (3.3 series). I'll come back to this issue after.