Fix scope of transitive target name lookups

In cmTarget, cmGeneratorTarget, and cmGeneratorExpressionEvaluator, fix
target name lookups to occur in the cmMakefile context of the target
that referenced the name, not the current 'head' target.  The context
matters for imported targets because they are directory-scoped instead
of globally unique.  We already do this in cmComputeLinkDepends and
cmComputeTargetDepends.

Extend the InterfaceLibrary test with an example covering this behavior.

4 files changed, 23 insertions, 2 deletions

diff --git a/Tests/InterfaceLibrary/CMakeLists.txt b/Tests/InterfaceLibrary/CMakeLists.txt
index 81b34e6..d4f49c2 100644
--- a/Tests/InterfaceLibrary/CMakeLists.txt
+++ b/Tests/InterfaceLibrary/CMakeLists.txt
@@ -8,8 +8,18 @@ target_compile_definitions(iface_nodepends INTERFACE IFACE_DEFINE)
 
 add_subdirectory(headerdir)
 
+# Add an interface target in a subdirectory that uses an imported interface.
+add_subdirectory(ifacedir)
+
+# Poison an imported interface with the same name as that in the subdir
+# to ensure that the transitive lookup occurs in the subdir.
+add_library(imp::iface INTERFACE IMPORTED)
+set_property(TARGET imp::iface APPEND PROPERTY COMPATIBLE_INTERFACE_BOOL SOMEPROP)
+set_property(TARGET imp::iface PROPERTY INTERFACE_SOMEPROP OFF)
+set_property(TARGET imp::iface PROPERTY INTERFACE_SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/does_not_exist.cpp)
+
 add_executable(InterfaceLibrary definetestexe.cpp)
-target_link_libraries(InterfaceLibrary iface_nodepends headeriface)
+target_link_libraries(InterfaceLibrary iface_nodepends headeriface subiface)
 
 add_subdirectory(libsdir)
 
diff --git a/Tests/InterfaceLibrary/definetestexe.cpp b/Tests/InterfaceLibrary/definetestexe.cpp
index e7a10c1..30f2925 100644
--- a/Tests/InterfaceLibrary/definetestexe.cpp
+++ b/Tests/InterfaceLibrary/definetestexe.cpp
@@ -15,7 +15,9 @@
 #error Expected IFACE_HEADER_BUILDDIR
 #endif
 
+extern int sub();
+
 int main(int,char**)
 {
-  return 0;
+  return sub();
 }
diff --git a/Tests/InterfaceLibrary/ifacedir/CMakeLists.txt b/Tests/InterfaceLibrary/ifacedir/CMakeLists.txt
new file mode 100644
index 0000000..228715e
--- /dev/null
+++ b/Tests/InterfaceLibrary/ifacedir/CMakeLists.txt
@@ -0,0 +1,8 @@
+add_library(imp::iface INTERFACE IMPORTED)
+set_property(TARGET imp::iface APPEND PROPERTY COMPATIBLE_INTERFACE_BOOL SOMEPROP)
+set_property(TARGET imp::iface PROPERTY INTERFACE_SOMEPROP ON)
+set_property(TARGET imp::iface PROPERTY INTERFACE_SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/sub.cpp)
+
+add_library(subiface INTERFACE)
+target_link_libraries(subiface INTERFACE imp::iface)
+set_property(TARGET subiface PROPERTY INTERFACE_SOMEPROP ON)
diff --git a/Tests/InterfaceLibrary/ifacedir/sub.cpp b/Tests/InterfaceLibrary/ifacedir/sub.cpp
new file mode 100644
index 0000000..165a66a
--- /dev/null
+++ b/Tests/InterfaceLibrary/ifacedir/sub.cpp
@@ -0,0 +1 @@
+int sub() { return 0; }