This repository contains a bunch of tests for binary compatiblity. Creating automated tests for failures is difficult, because not all binary incompatible changes cause exceptions. In fact, the dangerous kind silently pass even the most innocent test.
This repository is an attempt to prove broken behavior via minimal test cases that highlight issues for users. The passing test cases should give users an idea of how to proceed in the land of Scala and acheive their own binary compatible libraries.
Also, this code should be a hint that automated tool support (like typesafe's MiMa) are an almost necessity of library releases to ensure binary compatibility.
The build is an sbt project. Simply run sbt in the base directory. SBT will discover all sub projects and wire them into the build.
To see the output of a single binary compatiblity test, run:
sbt> <project-name>/bc-run
You'll see a result like the following:
> trait-lazy-val-to-def/bc-run
[info] Compiling 1 Scala source to /home/jsuereth/projects/personal/binary-resilience/trait-lazy-val-to-def/target/scala-2.9.1/classes...
[info] Compiling 1 Scala source to /home/jsuereth/projects/personal/binary-resilience/trait-lazy-val-to-def/target/scala-2.9.1/second-compile-classes...
[info] Running Main
Calculating Foo.x
1
1
The above is actually a failed test. We're working on better ways to test effects besides println statements.
For any of the tests, you can run:
sbt> <project-name>/bc-show-diff
And you'll get an output like the following:
> trait-lazy-val-to-def/bc-show-diff
trait Foo { | trait Foo {
lazy val x = 1 | def x = { println("Calculating Foo.x"); 1 }
} | }
|
object Main { |
|
def main(args: Array[String]): Unit = { |
val tmp = new Foo {} |
println(tmp.x) |
println(tmp.x) |
} |
} |
which will let you see how the test is set up, and what is changing.
Copyright (c) 2012, Josh Suereth All rights reserved.
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