Incremental compilation does not work if modified code is imported from a module that exported said code from elsewhere

phrmoy · August 20, 2023, 5:57pm

I am not sure if this should have gone to the user group or not, but since this seems to be a bug of sorts…

I am having these incremental compilation issues (very frequently) that force me to manually delete my bloop folder in order for bloop/sbt to compile.

Development is really hindered at this point. I am not sure how to proceed forward to improve this situation, and I am already many months in this Scala code base, quite the investment.

I have opened a ticket, which could not be reproduced, and also posted a video describing and showing the problem.

Any advice would be appreciated. Thank you!

Pedro

github.com/lampepfl/dotty

Incremental compilation does not work if modified code is imported from a module that exported said code from elsewhere.

opened 10:57PM - 15 Jul 23 UTC

phrmoy

itype:bug stat:cannot reproduce stat:needs minimization area:incremental-compilation area:export

## Compiler version 3.3.0 ## Minimized code ModuleA.scala ```Scala ob…ject ModuleA { def func(x:Int) = x } ``` ModuleB.scala ```Scala object ModuleB { export ModuleA.{*} } ``` ModuleC.scala ```Scala object ModuleC { import ModuleB.{*} println(func(0)) } ``` The above works. Now if I change the ModuleA.scala to ModuleA.scala ```Scala object ModuleA { def func(x:Int, y:Int) = x + y } ``` and change ModuleC.scala to ModuleC.scala ```Scala object ModuleC { import ModuleB.{*} println(func(0,0)) } ``` Both SBT and bloop fail to compile the code. Bloop v1.5.6. SBT v1.8.3 ## Output From SBT ``` [error] 11 | println(func(0, 0)) [error] | ^^^^ [error] | Found: (Int, Int) [error] | Required: Int [error] |---------------------------------------------------------------------------- [error] | Explanation (enabled by `-explain`) [error] |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ``` From Bloop ``` Found: (Int, Int) Required: Int ``` ## Expectation Expected code to compile normally.

smarter · August 21, 2023, 1:32pm

I see you mentioned in the issue you should be able to share a git repo reproducing the issue, that should really help get to the bottom of this. Meanwhile, I would recommend dropping the use of export on objects and replace it by extra import at use-sites instead. While it’s tempting to use export like this, it has some known issues which are still being worked on: Fix #17201: do no call ensureCompleted for import symbol by dos65 · Pull Request #17304 · lampepfl/dotty · GitHub