Revert "target_link_libraries: Allow use with targets in other directories"

Revert commit v3.12.0-rc1~82^2 (target_link_libraries: Allow use with
targets in other directories, 2018-05-11).  The RHS target scoping and
visibility rules are not clear and will need further investigation
before the feature can be added.

Issue: #17943

Help/command/target_link_libraries.rst

@@ -18,7 +18,7 @@ All of them have the general form::
 
   target_link_libraries(<target> ... <item>... ...)
 
-The named ``<target>`` must have been created by
+The named ``<target>`` must have been created in the current directory by
 a command such as :command:`add_executable` or :command:`add_library` and
 must not be an :ref:`ALIAS target <Alias Targets>`.
 Repeated calls for the same ``<target>`` append items in the order called.

Help/release/3.12.rst

@@ -81,9 +81,6 @@ Commands
   :ref:`Object Libraries`.  Linking to an object library uses its object
   files in direct dependents and also propagates usage requirements.
 
-* The :command:`target_link_libraries` command may now be called
-  to modify targets created outside the current directory.
-
 Variables
 ---------
 

Source/cmTargetLinkLibrariesCommand.cxx

@@ -365,7 +365,7 @@ bool cmTargetLinkLibrariesCommand::HandleLibrary(const std::string& lib,
   if (this->CurrentProcessingState != ProcessingKeywordLinkInterface &&
       this->CurrentProcessingState != ProcessingPlainLinkInterface) {
 
-    // Find target on the LHS locally
+    // Assure that the target on the LHS was created in the current directory.
     cmTarget* t =
       this->Makefile->FindLocalNonAliasTarget(this->Target->GetName());
     if (!t) {
@@ -378,18 +378,11 @@ bool cmTargetLinkLibrariesCommand::HandleLibrary(const std::string& lib,
         }
       }
     }
-
-    // If no local target has been found, find it in the global scope
-    if (!t) {
-      t = this->Makefile->GetGlobalGenerator()->FindTarget(
-        this->Target->GetName(), true);
-    }
-
     if (!t) {
       std::ostringstream e;
       e << "Attempt to add link library \"" << lib << "\" to target \""
         << this->Target->GetName()
-        << "\" which does not exist or is an alias target.";
+        << "\" which is not built in this directory.";
       this->Makefile->IssueMessage(cmake::FATAL_ERROR, e.str());
       return false;
     }

Tests/RunCMake/target_link_libraries/RunCMakeTest.cmake

@@ -8,10 +8,7 @@ run_cmake(ImportedTarget)
 run_cmake(ImportedTargetFailure)
 run_cmake(MixedSignature)
 run_cmake(Separate-PRIVATE-LINK_PRIVATE-uses)
-run_cmake(SubDirImportedTarget)
 run_cmake(SubDirTarget)
-run_cmake(SubDirTarget-UNKNOWN-IMPORTED)
-run_cmake(SubDirTarget-UNKNOWN-IMPORTED-GLOBAL)
 run_cmake(SharedDepNotTarget)
 run_cmake(StaticPrivateDepNotExported)
 run_cmake(StaticPrivateDepNotTarget)

Tests/RunCMake/target_link_libraries/SubDirImportedTarget-stdout.txt

@@ -1,4 +0,0 @@
--- mainexeUnknownImportedGlobal: mainlib;sublib
--- mainlibUnknownImportedGlobal: mainlib;sublib
--- subexeUnknownImportedGlobal: mainlib;sublib
--- sublibUnknownImportedGlobal: mainlib;sublib

Tests/RunCMake/target_link_libraries/SubDirImportedTarget.cmake

@@ -1,17 +0,0 @@
-enable_language(C)
-
-add_executable(mainexeUnknownImportedGlobal IMPORTED GLOBAL)
-add_library(mainlibUnknownImportedGlobal UNKNOWN IMPORTED GLOBAL)
-add_library(mainlib empty.c)
-
-add_subdirectory(SubDirImportedTarget)
-
-target_link_libraries(subexeUnknownImportedGlobal INTERFACE mainlib)
-target_link_libraries(subexeUnknownImportedGlobal INTERFACE sublib)
-get_property(subexeUnknownImportedGlobal_libs TARGET subexeUnknownImportedGlobal PROPERTY INTERFACE_LINK_LIBRARIES)
-message(STATUS "subexeUnknownImportedGlobal: ${subexeUnknownImportedGlobal_libs}")
-
-target_link_libraries(sublibUnknownImportedGlobal INTERFACE mainlib)
-target_link_libraries(sublibUnknownImportedGlobal INTERFACE sublib)
-get_property(sublibUnknownImportedGlobal_libs TARGET sublibUnknownImportedGlobal PROPERTY INTERFACE_LINK_LIBRARIES)
-message(STATUS "sublibUnknownImportedGlobal: ${sublibUnknownImportedGlobal_libs}")

Tests/RunCMake/target_link_libraries/SubDirImportedTarget/CMakeLists.txt

@@ -1,13 +0,0 @@
-add_executable(subexeUnknownImportedGlobal IMPORTED GLOBAL)
-add_library(sublibUnknownImportedGlobal UNKNOWN IMPORTED GLOBAL)
-add_library(sublib ../empty.c)
-
-target_link_libraries(mainexeUnknownImportedGlobal INTERFACE mainlib)
-target_link_libraries(mainexeUnknownImportedGlobal INTERFACE sublib)
-get_property(mainexeUnknownImportedGlobal_libs TARGET mainexeUnknownImportedGlobal PROPERTY INTERFACE_LINK_LIBRARIES)
-message(STATUS "mainexeUnknownImportedGlobal: ${mainexeUnknownImportedGlobal_libs}")
-
-target_link_libraries(mainlibUnknownImportedGlobal INTERFACE mainlib)
-target_link_libraries(mainlibUnknownImportedGlobal INTERFACE sublib)
-get_property(mainlibUnknownImportedGlobal_libs TARGET mainlibUnknownImportedGlobal PROPERTY INTERFACE_LINK_LIBRARIES)
-message(STATUS "mainlibUnknownImportedGlobal: ${mainlibUnknownImportedGlobal_libs}")

Tests/RunCMake/target_link_libraries/SubDirTarget-UNKNOWN-IMPORTED-GLOBAL-stdout.txt

@@ -1,2 +0,0 @@
--- mainexe: mainlibUnknownImportedGlobal;sublibUnknownImportedGlobal
--- subexe: mainlibUnknownImportedGlobal;sublibUnknownImportedGlobal

Tests/RunCMake/target_link_libraries/SubDirTarget-UNKNOWN-IMPORTED-GLOBAL.cmake

@@ -1,11 +0,0 @@
-enable_language(C)
-
-add_executable(mainexe empty.c)
-add_library(mainlibUnknownImportedGlobal UNKNOWN IMPORTED GLOBAL)
-
-add_subdirectory(SubDirTarget-UNKNOWN-IMPORTED-GLOBAL)
-
-target_link_libraries(subexe mainlibUnknownImportedGlobal)
-target_link_libraries(subexe sublibUnknownImportedGlobal)
-get_property(subexe_libs TARGET subexe PROPERTY INTERFACE_LINK_LIBRARIES)
-message(STATUS "subexe: ${subexe_libs}")

Tests/RunCMake/target_link_libraries/SubDirTarget-UNKNOWN-IMPORTED-GLOBAL/CMakeLists.txt

@@ -1,7 +0,0 @@
-add_executable(subexe ../empty.c)
-add_library(sublibUnknownImportedGlobal UNKNOWN IMPORTED GLOBAL)
-
-target_link_libraries(mainexe mainlibUnknownImportedGlobal)
-target_link_libraries(mainexe sublibUnknownImportedGlobal)
-get_property(mainexe_libs TARGET mainexe PROPERTY INTERFACE_LINK_LIBRARIES)
-message(STATUS "mainexe: ${mainexe_libs}")

Tests/RunCMake/target_link_libraries/SubDirTarget-UNKNOWN-IMPORTED-stdout.txt

@@ -1,2 +0,0 @@
--- mainexe: mainlibUnknownImported;sublibUnknownImported
--- subexe: mainlibUnknownImported;sublibUnknownImported

Tests/RunCMake/target_link_libraries/SubDirTarget-UNKNOWN-IMPORTED.cmake

@@ -1,11 +0,0 @@
-enable_language(C)
-
-add_executable(mainexe empty.c)
-add_library(mainlibUnknownImported UNKNOWN IMPORTED)
-
-add_subdirectory(SubDirTarget-UNKNOWN-IMPORTED)
-
-target_link_libraries(subexe mainlibUnknownImported)
-target_link_libraries(subexe sublibUnknownImported)
-get_property(subexe_libs TARGET subexe PROPERTY INTERFACE_LINK_LIBRARIES)
-message(STATUS "subexe: ${subexe_libs}")

Tests/RunCMake/target_link_libraries/SubDirTarget-UNKNOWN-IMPORTED/CMakeLists.txt

@@ -1,7 +0,0 @@
-add_executable(subexe ../empty.c)
-add_library(sublibUnknownImported UNKNOWN IMPORTED)
-
-target_link_libraries(mainexe mainlibUnknownImported)
-target_link_libraries(mainexe sublibUnknownImported)
-get_property(mainexe_libs TARGET mainexe PROPERTY INTERFACE_LINK_LIBRARIES)
-message(STATUS "mainexe: ${mainexe_libs}")

Tests/RunCMake/target_link_libraries/SubDirTarget-result.txt

@@ -0,0 +1 @@
+1

Tests/RunCMake/target_link_libraries/SubDirTarget-stderr.txt

@@ -0,0 +1,5 @@
+^CMake Error at SubDirTarget.cmake:[0-9]+ \(target_link_libraries\):
+  Attempt to add link library "m" to target "subexe" which is not built in
+  this directory.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:[0-9]+ \(include\)$

Tests/RunCMake/target_link_libraries/SubDirTarget-stdout.txt

@@ -1,2 +0,0 @@
--- mainexe: mainlib;sublib
--- subexe: mainlib;sublib

Tests/RunCMake/target_link_libraries/SubDirTarget.cmake

@@ -1,11 +1,3 @@
 enable_language(C)
-
-add_executable(mainexe empty.c)
-add_library(mainlib empty.c)
-
 add_subdirectory(SubDirTarget)
-
-target_link_libraries(subexe mainlib)
-target_link_libraries(subexe sublib)
-get_property(subexe_libs TARGET subexe PROPERTY INTERFACE_LINK_LIBRARIES)
-message(STATUS "subexe: ${subexe_libs}")
+target_link_libraries(subexe m)

Tests/RunCMake/target_link_libraries/SubDirTarget/CMakeLists.txt

@@ -1,7 +1 @@
 add_executable(subexe ../empty.c)
-add_library(sublib ../empty.c)
-
-target_link_libraries(mainexe mainlib)
-target_link_libraries(mainexe sublib)
-get_property(mainexe_libs TARGET mainexe PROPERTY INTERFACE_LINK_LIBRARIES)
-message(STATUS "mainexe: ${mainexe_libs}")