jwoertink / compiler_bug

compiler_bug

This project shows a reproducible bug where JSON content doesn't fully return when the --release flag is added.

Testing this

• git clone this repo
• cd in to the repo
• shards
• crystal src/start_server.cr
• open http://localhost:3000/ in Chrome (it's easier to see here)
• Notice everything is ok.
• ctrl-C to stop the server
• crystal build --release src/start_server.cr
• ./start_server
• Refresh the chrome page
• Notice the logs throw Index out of bounds, and the response is cut off

Bisecting against Crystal

In order to test this against different commits in Crystal, you'll need to clone the Crystal compiler, and have Docker installed.

• mkdir sandbox && cd sandbox
• git clone https://github.com/crystal-lang/crystal.git lang
• git clone https://github.com/jwoertink/compiler_bug.git demo
• The last good version this worked on was Crystal 1.1.1 (6d9a1d5)
• It stopped working in 1.2.0
• cd lang
• git bisect start
• git bisect good 6d9a1d5
• git bisect bad 9f90efe
• cd ..
• sudo docker run --rm -it -v $PWD:/app -w /app crystallang/crystal:1.1.1-build bash
• From here, you're in the Docker container with access to this repo, and Crystal.
• cd lang
• make clean && make
• cd ../demo
• Then /app/lang/bin/crystal build --release src/start_server.cr from this repo
• Back on the local machine, you should be able to ./demo/start_server and boot this up.