From 26e2449263d423c18530db6f5591a04842d30e3e Mon Sep 17 00:00:00 2001 From: Martin Duhem Date: Sat, 14 Jun 2014 16:58:10 +0200 Subject: [PATCH] Never inspect twice the same macro application In Scala 2.10.4, this macro can produce a stack overflow : def foo(a: Any): Any = macro impl def impl(c: Context)(a: c.Expr[Any]): c.Expr[Any] = a Here, an application such as `foo(someVal)` will produce the expansion `someVal`. As expected, `someVal` has `original` tree `foo(someVal)`, but if we inspect this tree, we will find that `someVal` has an original tree, but it shouldn't. Moreover, in Scala 2.11, some macros have their own application as `original` trees. See sbt/sbt#1237 for a description of these problems. This commit fixes these two problems. Fixes sbt/sbt#1237 --- .../src/main/scala/xsbt/ExtractUsedNames.scala | 10 +++++----- .../macro-arg-dep-stackoverflow/{pending => test} | 0 2 files changed, 5 insertions(+), 5 deletions(-) rename sbt/src/sbt-test/source-dependencies/macro-arg-dep-stackoverflow/{pending => test} (100%) diff --git a/compile/interface/src/main/scala/xsbt/ExtractUsedNames.scala b/compile/interface/src/main/scala/xsbt/ExtractUsedNames.scala index 85b78e0d9..4d69f0d9b 100644 --- a/compile/interface/src/main/scala/xsbt/ExtractUsedNames.scala +++ b/compile/interface/src/main/scala/xsbt/ExtractUsedNames.scala @@ -56,12 +56,12 @@ class ExtractUsedNames[GlobalType <: CallbackGlobal](val global: GlobalType) ext def handleTreeNode(node: Tree): Unit = { def handleMacroExpansion(original: Tree): Unit = { - // Some macros seem to have themselves registered as original tree. - // In this case, we only need to handle the children of the original tree, - // because we already handled the expanded tree. + // Some macros seem to be their own orignal tree, or appear in the children of their + // original tree. To prevent infinite loops, we need to filter out nodes that we already + // handled. + // This is only relevant for Scala 2.10.4 // See https://issues.scala-lang.org/browse/SI-8486 - if (original == node) original.children.foreach(handleTreeNode) - else original.foreach(handleTreeNode) + original.filter(_ ne node).foreach(handleTreeNode) } def handleClassicTreeNode(node: Tree): Unit = node match { diff --git a/sbt/src/sbt-test/source-dependencies/macro-arg-dep-stackoverflow/pending b/sbt/src/sbt-test/source-dependencies/macro-arg-dep-stackoverflow/test similarity index 100% rename from sbt/src/sbt-test/source-dependencies/macro-arg-dep-stackoverflow/pending rename to sbt/src/sbt-test/source-dependencies/macro-arg-dep-stackoverflow/test