From 54d12f0581f6401c7693ccb0e3105868da19cec2 Mon Sep 17 00:00:00 2001
From: Jason Zaugg <jzaugg@gmail.com>
Date: Fri, 7 Nov 2014 23:12:43 +1000
Subject: SI-8502 Improve resiliance to absent packages

When unpickling a class, we create stub symbols for references
to classes absent from the current classpath. If these references
only appear in method signatures that aren't called, we can
proceed with compilation. This is in line with javac.

We're getting better at this, but there are still some gaps.
This bug is about the behaviour when a package is completely
missing, rather than just a single class within that package.

To make this work we have to add two special cases to the unpickler:

  - When unpickling a `ThisType`, convert a `StubTermSymbol` into
    a `StubTypeSymbol`. We hit this when unpickling
    `ThisType(missingPackage)`.
  - When unpickling a reference to `<owner>.name` where `<owner>`
    is a stub symbol, don't call info on that owner, but rather
    allow the enclosing code in `readSymbol` fall through to
    create a stub for the member.

The test case was distilled from an a problem that a Spray user
encountered when Akka was missing from the classpath.

Two existing test cases have progressed, and the checkfiles are
accordingly updated.
---
 test/files/neg/t5148.check |  7 ++++++-
 test/files/run/t6440.check |  9 ++++-----
 test/files/run/t6440.scala |  2 +-
 test/files/run/t8502.scala | 41 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 52 insertions(+), 7 deletions(-)
 create mode 100644 test/files/run/t8502.scala

(limited to 'test')

diff --git a/test/files/neg/t5148.check b/test/files/neg/t5148.check
index 0de4fe2d4c..286ed9e04a 100644
--- a/test/files/neg/t5148.check
+++ b/test/files/neg/t5148.check
@@ -1,6 +1,11 @@
 error: missing or invalid dependency detected while loading class file 'Imports.class'.
+Could not access type Wrapper in class scala.tools.nsc.interpreter.IMain.Request,
+because it (or its dependencies) are missing. Check your build definition for
+missing or conflicting dependencies. (Re-run with `-Ylog-classpath` to see the problematic classpath.)
+A full rebuild may help if 'Imports.class' was compiled against an incompatible version of scala.tools.nsc.interpreter.IMain.Request.
+error: missing or invalid dependency detected while loading class file 'Imports.class'.
 Could not access type Request in class scala.tools.nsc.interpreter.IMain,
 because it (or its dependencies) are missing. Check your build definition for
 missing or conflicting dependencies. (Re-run with `-Ylog-classpath` to see the problematic classpath.)
 A full rebuild may help if 'Imports.class' was compiled against an incompatible version of scala.tools.nsc.interpreter.IMain.
-one error found
+two errors found
diff --git a/test/files/run/t6440.check b/test/files/run/t6440.check
index 2358f08fcc..4d8618182b 100644
--- a/test/files/run/t6440.check
+++ b/test/files/run/t6440.check
@@ -1,5 +1,4 @@
-pos: source-newSource1.scala,line-9,offset=109 missing or invalid dependency detected while loading class file 'U.class'.
-Could not access term pack1 in package <root>,
-because it (or its dependencies) are missing. Check your build definition for
-missing or conflicting dependencies. (Re-run with `-Ylog-classpath` to see the problematic classpath.)
-A full rebuild may help if 'U.class' was compiled against an incompatible version of <root>. ERROR
+pos: source-newSource1.scala,line-9,offset=109 reference to U is ambiguous;
+it is imported twice in the same scope by
+import pack2._
+and import X._ ERROR
diff --git a/test/files/run/t6440.scala b/test/files/run/t6440.scala
index 5a3a4150d9..94eda3642e 100644
--- a/test/files/run/t6440.scala
+++ b/test/files/run/t6440.scala
@@ -41,7 +41,7 @@ object Test extends StoreReporterDirectTest {
     assert(tClass.delete())
     assert(pack1.delete())
 
-    // bad symbolic reference error expected (but no stack trace!)
+    // should report ambiguous import, despite the fact that a parent of pack2.U is absent
     compileCode(app)
     println(filteredInfos.mkString("\n"))
   }
diff --git a/test/files/run/t8502.scala b/test/files/run/t8502.scala
new file mode 100644
index 0000000000..903e573711
--- /dev/null
+++ b/test/files/run/t8502.scala
@@ -0,0 +1,41 @@
+import scala.tools.partest._
+import java.io.File
+
+object Test extends StoreReporterDirectTest {
+  def code = ???
+
+  def compileCode(code: String) = {
+    val classpath = List(sys.props("partest.lib"), testOutput.path) mkString sys.props("path.separator")
+    compileString(newCompiler("-cp", classpath, "-d", testOutput.path))(code)
+  }
+
+  def show(): Unit = {
+    compileCode("""
+      object U {
+        def foo(log: vanishing.Vanishing) = ()
+      }
+
+      package vanishing {
+        class Vanishing
+      }
+      """)
+    assert(filteredInfos.isEmpty, filteredInfos)
+    deletePackage("vanishing")
+    compileCode("""
+      class Test {
+        U
+      }
+    """)
+    assert(storeReporter.infos.isEmpty, storeReporter.infos.mkString("\n")) // Included a MissingRequirementError before.
+  }
+
+  def deletePackage(name: String) {
+    val directory = new File(testOutput.path, name)
+    for (f <- directory.listFiles()) {
+      assert(f.getName.endsWith(".class"))
+      assert(f.delete())
+    }
+    assert(directory.listFiles().isEmpty)
+    assert(directory.delete())
+  }
+}
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