Segmentation fault when precompiling assets

[gabo-cs-zz]

Sometimes, when I make some changes to my .scss files in my Rails 6 app, I get the following when running rails assets:precompile

And also, when deploying to Heroku, I get
rubyDone in 4.85s. remote: /tmp/build_929254ebef3a89a9f40b4b26f007bde3/vendor/bundle/ruby/2.7.0/gems/sassc-2.3.0/lib/sassc/engine.rb:43: [BUG] Segmentation fault at 0x0000000000000000 remote: ruby 2.7.0p0 (2019-12-25 revision 647ee6f091) [x86_64-linux] -- Control frame information ----------------------------------------------- remote: c:0059 p:---- s:0449 e:000448 CFUNC :compile_data_context remote: c:0058 p:0314 s:0444 e:000443 METHOD /tmp/build_c5dc2802730effed8a887745a1195bb5/vendor/bundle/ruby/2.7.0/gems/sassc-2.3.0/lib/sassc/engine.rb:43
along with Aborted. remote: ! Precompiling assets failed. and it won't do the deployment successfully. I keep getting

remote:        
remote:        Aborted
remote: 
remote:  !
remote:  !     Precompiling assets failed.
remote:  !
remote:  !     Push rejected, failed to compile Ruby app.
remote: 
remote:  !     Push failed
remote: Verifying deploy...
remote: 
remote: !	Push rejected 

I don't get any other errors, so I think it's merely related to that compilation thing. I tried upgrading & downgrading the version of the gem but still can't get it through. I've been having this problem a while ago now and it had been sort of random, it wouldn't show up always, but recently, I get it almost every time I make a CSS change.

Can anybody help me out here? Thanks a lot in advance.

[josh-m-sharpe]

I believe I'm seeing the same thing while running tests on CircleCI. My test suite runs fine until it hits my integration tests which compile assets.

I've tried with these combos:
ruby 2.6.6 & sassc 2.4.0
ruby 2.6.6 & sassc 2.3.0

Test output:

# Running:

.........................../home/circleci/project/vendor/bundle/ruby/2.6.0/gems/sassc-2.3.0/lib/sassc/engine.rb:43: [BUG] Segmentation fault at 0x0000000000000000
ruby 2.6.6p146 (2020-03-31 revision 67876) [x86_64-linux]

-- Control frame information -----------------------------------------------
c:0048 p:---- s:0351 e:000350 CFUNC  :compile_data_context
c:0047 p:0318 s:0346 e:000345 METHOD /home/circleci/project/vendor/bundle/ruby/2.6.0/gems/sassc-2.3.0/lib/sassc/engine.rb:43
c:0046 p:0006 s:0334 e:000333 BLOCK  /home/circleci/project/vendor/bundle/ruby/2.6.0/gems/sassc-rails-2.1.2/lib/sassc/rails/template.rb:40
c:0045 p:0028 s:0331 e:000330 METHOD /home/circleci/project/vendor/bundle/ruby/2.6.0/gems/sprockets-4.0.2/lib/sprockets/utils.rb:138
c:0044 p:0164 s:0324 e:000323 METHOD /home/circleci/project/vendor/bundle/ruby/2.6.0/gems/sassc-rails-2.1.2/lib/sassc/rails/template.rb:39
c:0043 p:0053 s:0315 e:000314 METHOD /home/circleci/project/vendor/bundle/ruby/2.6.0/gems/sprockets-4.0.2/lib/sprockets/processor_utils.rb:84
c:0042 p:0016 s:0307 e:000306 BLOCK  /home/circleci/project/vendor/bundle/ruby/2.6.0/gems/sprockets-4.0.2/lib/sprockets/processor_utils.rb:66 [FINISH]
c:0041 p:---- s:0302 e:000301 CFUNC  :reverse_each
c:0040 p:0039 s:0298 e:000297 METHOD /home/circleci/project/vendor/bundle/ruby/2.6.0/gems/sprockets-4.0.2/lib/sprockets/processor_utils.rb:65
c:0039 p:0015 s:0290 e:000289 BLOCK  /home/circleci/project/vendor/bundle/ruby/2.6.0/gems/sprockets-4.0.2/lib/sprockets/processor_utils.rb:22
c:0038 p:0013 s:0285 e:000284 METHOD /home/circleci/project/vendor/bundle/ruby/2.6.0/gems/sprockets-4.0.2/lib/sprockets/processor_utils.rb:33
c:0037 p:0053 s:0280 e:000279 METHOD /home/circleci/project/vendor/bundle/ruby/2.6.0/gems/sprockets-4.0.2/lib/sprockets/processor_utils.rb:84
c:0036 p:0016 s:0272 e:000271 BLOCK  /home/circleci/project/vendor/bundle/ruby/2.6.0/gems/sprockets-4.0.2/lib/sprockets/processor_utils.rb:66 [FINISH]
c:0035 p:---- s:0267 e:000266 CFUNC  :reverse_each

[inopinatus]

I saw something very similar after upgrading an older app to Sprockets 4, which introduced concurrent asset compilation. I'm guessing that something within sassc-ruby or libsass isn't thread-safe.

The problem goes away (for me) with Sprockets.export_concurrent = false in an initializer.

[gabo-cs-zz]

I saw something very similar after upgrading an older app to Sprockets 4, which introduced concurrent asset compilation. I'm guessing that something within sassc-ruby or libsass isn't thread-safe.

The problem goes away (for me) with Sprockets.export_concurrent = false in an initializer.

Yes, that's same as doing

config.assets.configure do |env|
    env.export_concurrent = false
end

in the application.rb, but not always works.

[murtra]

I'm having the same crash in development mode for an app that was recently upgraded to Sprockets 4 (Ruby 2.6.6, Rails 6.0.3). It's a random thing but happens very often.

Disabling concurrent asset compilation fixed the issue for me.

[rlgreen91]

I'm seeing the same issues in our app, which uses Ruby 2.6.6 and Rails 5.0.7. The gem is at the most recent version, 2.4.0. This also occurred after an update to Sprockets 4.

The recommended solution of disabling concurrent asset compilation does not work when running our test suite locally.