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Compatibility with other libraries and frameworks #23

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anatoliykmetyuk opened this issue Apr 24, 2014 · 1 comment
Open

Compatibility with other libraries and frameworks #23

anatoliykmetyuk opened this issue Apr 24, 2014 · 1 comment
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@anatoliykmetyuk
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While testing subscript actors, I've came across the problem that akka 2.3.2 throwed exceptions that some core class is not found (like, class PartialFunction). Akka 2.3.0 worked OK. Then, after updating my repository with new commits, Akka 2.3.0 stopped working for very same cause, and akka 2.3.2 worked normally.

This means there may be compatibility issues with other libs too, which significantly decteases usability. Though it is not vital for the moment and doesn't harm our current tasks significantly, I think we should investigate on question when we have less workload.
@anatoliykmetyuk
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I've noticed a pattern in Akka compatibility issues: if SubScript was compiled with version A of Akka, then no other program that uses SubScript Actors will compile with version A of Akka, where A is either 2.3.2 or 2.3.0 (maybe also other versions, I have not checked.

anatoliykmetyuk pushed a commit to anatoliykmetyuk/subscript that referenced this issue Mar 4, 2015
@retronym
SI-7965 Support calls to MethodHandle.{invoke,invokeExact}
c1d092a 
These methods are "signature polymorphic", which means that compiler
should not:
  1. adapt the arguments to `Object`
  2. wrap the repeated parameters in an array
  3. adapt the result type to `Object`, but instead treat it as it
     it already conforms to the expected type.

Dispiritingly, my initial attempt to implement this touched the type
checker, uncurry, erasure, and the backend.

However, I realized we could centralize handling of this in the typer
if at each application we substituted the signature polymorphic
symbol with a clone that carried its implied signature, which is
derived from the types of the arguments (typechecked without an
expected type) and position within and enclosing cast or block.

The test case requires Java 7+ to compile so is currently embedded
in a conditionally compiled block of code in a run test.

We ought to create a partest category for modern JVMs so we can
write such tests in a more natural style.

Here's how this looks in bytecode. Note the `bipush` / `istore`
before/after the invocation of `invokeExact`, and the descriptor
`(LO$;I)I`.

```
% cat sandbox/poly-sig.scala && qscala Test && echo ':javap Test$#main' | qscala
import java.lang.invoke._

object O {
  def bar(x: Int): Int = -x
}

object Test {
  def main(args: Array[String]): Unit = {
    def lookup(name: String, params: Array[Class[_]], ret: Class[_]) = {
      val lookup = java.lang.invoke.MethodHandles.lookup
      val mt = MethodType.methodType(ret, params)
      lookup.findVirtual(O.getClass, name, mt)
    }
    def lookupBar = lookup("bar", Array(classOf[Int]), classOf[Int])

    val barResult: Int = lookupBar.invokeExact(O, 42)
    ()
  }
}

scala> :javap Test$#main
  public void main(java.lang.String[]);
    descriptor: ([Ljava/lang/String;)V
    flags: ACC_PUBLIC
    Code:
      stack=3, locals=3, args_size=2
         0: aload_0
         1: invokespecial AndreVanDelft#18                 // Method lookupBar$1:()Ljava/lang/invoke/MethodHandle;
         4: getstatic     AndreVanDelft#23                 // Field O$.MODULE$:LO$;
         7: bipush        42
         9: invokevirtual AndreVanDelft#29                 // Method java/lang/invoke/MethodHandle.invokeExact:(LO$;I)I
        12: istore_2
        13: return
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
            0      14     0  this   LTest$;
            0      14     1  args   [Ljava/lang/String;
           13       0     2 barResult   I
      LineNumberTable:
        line 16: 0
}
```

I've run this test across our active JVMs:

```
% for v in 1.6 1.7 1.8; do java_use $v; pt --terse test/files/run/t7965.scala || break; done
java version "1.6.0_65"
Java(TM) SE Runtime Environment (build 1.6.0_65-b14-466.1-11M4716)
Java HotSpot(TM) 64-Bit Server VM (build 20.65-b04-466.1, mixed mode)
Selected 1 tests drawn from specified tests

.

1/1 passed (elapsed time: 00:00:02)
Test Run PASSED
java version "1.7.0_71"
Java(TM) SE Runtime Environment (build 1.7.0_71-b14)
Java HotSpot(TM) 64-Bit Server VM (build 24.71-b01, mixed mode)
Selected 1 tests drawn from specified tests

.

1/1 passed (elapsed time: 00:00:07)
Test Run PASSED
java version "1.8.0_25"
Java(TM) SE Runtime Environment (build 1.8.0_25-b17)
Java HotSpot(TM) 64-Bit Server VM (build 25.25-b02, mixed mode)
Selected 1 tests drawn from specified tests

.

1/1 passed (elapsed time: 00:00:05)
Test Run PASSED
```
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