C-y kills Ammonite

[Blaisorblade]

Most Scala REPLs (including Ammonite right now) tend* to die after I type C-y (that is, Ctrl-y) and resume, instead of pasting what I just C-k'ed, with an InterruptedException on reading.

I tracked this down to C-y causing (by default) a delayed suspend, that is a suspend when the process reads from input (like C-z). This can be disabled through stty dsusp undef, also used in JLine, but that's commented out with a "blows up on ubuntu" comment. Alternatively, one could catch the InterruptedException, match on the error message and ignore the exceptions with the right message (although that's probably not extremely robust) — you often don't want to ignore all InterruptedException.

*That is, they repeatably die until this bug is somewhen fixed — both SBT and scala had it at some point.

[Blaisorblade]

Stack trace from inside sbt:

$ fg
sbt
[error] (run-main-0) java.io.IOException: Resource temporarily unavailable
java.io.IOException: Resource temporarily unavailable
    at java.io.FileInputStream.readBytes(Native Method)
    at java.io.FileInputStream.read(FileInputStream.java:272)
    at java.io.BufferedInputStream.read1(BufferedInputStream.java:273)
    at java.io.BufferedInputStream.read(BufferedInputStream.java:334)
    at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:283)
    at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:325)
    at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:177)
    at sun.nio.cs.StreamDecoder.read0(StreamDecoder.java:126)
    at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:112)
    at java.io.InputStreamReader.read(InputStreamReader.java:168)
    at ammonite.terminal.TermCore$$anonfun$readLine$1.apply$mcI$sp(TermCore.scala:213)
    at ammonite.terminal.TermCore$$anonfun$readLine$1.apply(TermCore.scala:213)
    at ammonite.terminal.TermCore$$anonfun$readLine$1.apply(TermCore.scala:213)
    at ammonite.terminal.LazyList.head$lzycompute(Utils.scala:89)
    at ammonite.terminal.LazyList.head(Utils.scala:87)
    at ammonite.terminal.FilterTools$$anon$2.rec$1(FilterTools.scala:28)
    at ammonite.terminal.FilterTools$$anon$2.isDefinedAt(FilterTools.scala:31)
    at ammonite.terminal.FilterTools$$anon$2.isDefinedAt(FilterTools.scala:23)
    at ammonite.terminal.FilterTools$$anon$1$$anonfun$isDefinedAt$1.apply(FilterTools.scala:13)
    at ammonite.terminal.FilterTools$$anon$1$$anonfun$isDefinedAt$1.apply(FilterTools.scala:13)
    at scala.collection.IndexedSeqOptimized$class.prefixLengthImpl(IndexedSeqOptimized.scala:38)
    at scala.collection.IndexedSeqOptimized$class.exists(IndexedSeqOptimized.scala:46)
    at scala.collection.mutable.WrappedArray.exists(WrappedArray.scala:35)
    at ammonite.terminal.FilterTools$$anon$1.isDefinedAt(FilterTools.scala:13)
    at ammonite.terminal.TermCore$DelegateFilter$class.isDefinedAt(TermCore.scala:105)
    at ammonite.terminal.GUILikeFilters$SelectionFilter.isDefinedAt(GUILikeFilters.scala:15)
    at ammonite.terminal.GUILikeFilters$SelectionFilter.isDefinedAt(GUILikeFilters.scala:15)
    at scala.PartialFunction$class.applyOrElse(PartialFunction.scala:123)
    at ammonite.terminal.GUILikeFilters$SelectionFilter.applyOrElse(GUILikeFilters.scala:15)
    at scala.PartialFunction$OrElse.apply(PartialFunction.scala:167)
    at ammonite.terminal.TermCore$.readChar$1(TermCore.scala:176)
    at ammonite.terminal.TermCore$.readLine(TermCore.scala:213)
    at ammonite.repl.frontend.FrontEnd$Ammonite$.readLine(FrontEnd.scala:148)
    at ammonite.repl.frontend.FrontEnd$Ammonite$.action(FrontEnd.scala:63)
    at ammonite.repl.Repl.action(Repl.scala:43)
    at ammonite.repl.Repl.loop$1(Repl.scala:76)
    at ammonite.repl.Repl.run(Repl.scala:94)
    at ammonite.repl.Repl$.run(Repl.scala:174)
    at ammonite.repl.Repl$$anonfun$main$1.apply(Repl.scala:142)
    at ammonite.repl.Repl$$anonfun$main$1.apply(Repl.scala:142)
    at scala.Option.foreach(Option.scala:257)
    at ammonite.repl.Repl$.main(Repl.scala:142)
    at ammonite.repl.Repl.main(Repl.scala)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)

[Blaisorblade]

I just verified that stty dsusp undef simply fails under Ubuntu 14.04 (inside/outside tmux). Can we just run the command and ignore failure? If this doesn't work, we could try to learn that dsusp is not supported (visible at least from stty -a, not sure whether also visible through infocmp).

[lihaoyi]

Can we just run the command and ignore failure? If this doesn't work, we could try to learn that dsusp is not supported (visible at least from stty -a, not sure whether also visible through infocmp).

Sure! I'm not sure if you already found this but it sounds like you have

https://github.com/lihaoyi/Ammonite/blob/master/terminal/src/main/scala/ammonite/terminal/Utils.scala#L66-L67

Feel free to try out whatever fix you want and send a PR

[Blaisorblade]

On it (yes, I found that snippet). Tests on project repl seem to fail on current master (no CI?) — it looks like my fix doesn't cause further regressions.

[lihaoyi]

Current master should work. Where are you seeing it broken?

[Blaisorblade]

Re the bug, see the PR #190.

Re the test failures, I looked into them. #192 might be a real bug.

The rest is mostly spurious failures — they affect at most Ammonite developers. Even then, some are worth a look:

• Tests use sources as test data? #191
• ProjectTests.finagle tries binding port 8080, even when it's already busy, and fails the test (it doesn't even error out, which would be more accurate).
• With a 64bit machine and only 1G of RAM for SBT, some tests fail (EulerTests.p5, AdvancedTests.compilerPlugin); I fixed my SBT config, but this is arguably worth documenting (more likely not).