Add policy CMP0040 to disallow custom commands on missing targets

Help/manual/cmake-policies.7.rst

@@ -73,3 +73,4 @@ All Policies
    /policy/CMP0037
    /policy/CMP0038
    /policy/CMP0039
+   /policy/CMP0040

Help/policy/CMP0040.rst

@@ -0,0 +1,16 @@
+CMP0040
+-------
+
+The target in the TARGET signature of add_custom_command() must exist.
+
+CMake 2.8.12 and lower silently ignored a custom command created with
+the TARGET signature of :command:`add_custom_command`
+if the target is unknown.
+
+The OLD behavior for this policy is to ignore custom commands
+for unknown targets. The NEW behavior for this policy is to report and error
+if the target referenced in :command:`add_custom_command` is unknown.
+
+This policy was introduced in CMake version 3.0.0.  CMake version
+|release| warns when the policy is not set and uses OLD behavior.  Use
+the cmake_policy command to set it to OLD or NEW explicitly.

Source/cmMakefile.cxx

@@ -884,8 +884,36 @@ cmMakefile::AddCustomCommandToTarget(const char* target,
 {
   // Find the target to which to add the custom command.
   cmTargets::iterator ti = this->Targets.find(target);
-  if(ti != this->Targets.end())
+
+  if(ti == this->Targets.end())
     {
+    cmake::MessageType messageType = cmake::AUTHOR_WARNING;
+    bool issueMessage = false;
+    switch(this->GetPolicyStatus(cmPolicies::CMP0040))
+      {
+      case cmPolicies::WARN:
+        issueMessage = true;
+      case cmPolicies::OLD:
+        break;
+      case cmPolicies::NEW:
+      case cmPolicies::REQUIRED_IF_USED:
+      case cmPolicies::REQUIRED_ALWAYS:
+        issueMessage = true;
+        messageType = cmake::FATAL_ERROR;
+      }
+
+    if(issueMessage)
+      {
+      cmOStringStream e;
+      e << (this->GetPolicies()
+        ->GetPolicyWarning(cmPolicies::CMP0040)) << "\n";
+      e << "The target name \"" << target << "\" is unknown in this context.";
+      IssueMessage(messageType, e.str().c_str());
+      }
+
+      return;
+    }
+
   if(ti->second.GetType() == cmTarget::OBJECT_LIBRARY)
     {
     cmOStringStream e;
@@ -913,7 +941,6 @@ cmMakefile::AddCustomCommandToTarget(const char* target,
       break;
     }
 }
-}
 
 //----------------------------------------------------------------------------
 cmSourceFile*

Source/cmPolicies.cxx

@@ -301,6 +301,11 @@ cmPolicies::cmPolicies()
     CMP0039, "CMP0039",
     "Utility targets may not have link dependencies.",
     3,0,0,0, cmPolicies::WARN);
+
+  this->DefinePolicy(
+    CMP0040, "CMP0040",
+    "The target in the TARGET signature of add_custom_command() must exist.",
+    3,0,0,0, cmPolicies::WARN);
 }
 
 cmPolicies::~cmPolicies()

Source/cmPolicies.h

@@ -92,6 +92,8 @@ public:
     /// should match a validity pattern.
     CMP0038, ///< Targets may not link directly to themselves
     CMP0039, ///< Utility targets may not have link dependencies
+    CMP0040, ///< The target in the TARGET signature of
+    /// add_custom_command() must exist.
 
     /** \brief Always the last entry.
      *

Tests/RunCMake/CMP0040/CMP0040-NEW-existing-target-result.txt

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

Tests/RunCMake/CMP0040/CMP0040-NEW-existing-target-stderr.txt

@@ -0,0 +1 @@
+^$

Tests/RunCMake/CMP0040/CMP0040-NEW-existing-target.cmake

@@ -0,0 +1,7 @@
+cmake_policy(SET CMP0040 NEW)
+
+add_library(foobar empty.cpp)
+
+add_custom_command(TARGET foobar PRE_BUILD
+  COMMAND "${CMAKE_COMMAND} -E echo hello world"
+)

Tests/RunCMake/CMP0040/CMP0040-NEW-missing-target-result.txt

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

Tests/RunCMake/CMP0040/CMP0040-NEW-missing-target-stderr.txt

@@ -0,0 +1,9 @@
+CMake Error at CMP0040-NEW-missing-target.cmake:3 \(add_custom_command\):
+  Policy CMP0040 is not set: The target in the TARGET signature of
+  add_custom_command\(\) must exist.  Run "cmake --help-policy CMP0040" for
+  policy details.  Use the cmake_policy command to set the policy and
+  suppress this warning.
++
+  The target name "foobar" is unknown in this context.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)

Tests/RunCMake/CMP0040/CMP0040-NEW-missing-target.cmake

@@ -0,0 +1,5 @@
+cmake_policy(SET CMP0040 NEW)
+
+add_custom_command(TARGET foobar PRE_BUILD
+  COMMAND "${CMAKE_COMMAND} -E hello world"
+)

Tests/RunCMake/CMP0040/CMP0040-OLD-existing-target-result.txt

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

Tests/RunCMake/CMP0040/CMP0040-OLD-existing-target-stderr.txt

@@ -0,0 +1 @@
+^$

Tests/RunCMake/CMP0040/CMP0040-OLD-existing-target.cmake

@@ -0,0 +1,7 @@
+cmake_policy(SET CMP0040 OLD)
+
+add_library(foobar empty.cpp)
+
+add_custom_command(TARGET foobar PRE_BUILD
+  COMMAND "${CMAKE_COMMAND} -E echo hello world"
+)

Tests/RunCMake/CMP0040/CMP0040-OLD-missing-target-result.txt

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

Tests/RunCMake/CMP0040/CMP0040-OLD-missing-target-stderr.txt

@@ -0,0 +1 @@
+^$

Tests/RunCMake/CMP0040/CMP0040-OLD-missing-target.cmake

@@ -0,0 +1,5 @@
+cmake_policy(SET CMP0040 OLD)
+
+add_custom_command(TARGET foobar PRE_BUILD
+  COMMAND "${CMAKE_COMMAND} -E echo hello world"
+)

Tests/RunCMake/CMP0040/CMP0040-WARN-missing-target-result.txt

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

Tests/RunCMake/CMP0040/CMP0040-WARN-missing-target-stderr.txt

@@ -0,0 +1,10 @@
+CMake Warning \(dev\) at CMP0040-WARN-missing-target.cmake:2 \(add_custom_command\):
+  Policy CMP0040 is not set: The target in the TARGET signature of
+  add_custom_command\(\) must exist.  Run "cmake --help-policy CMP0040" for
+  policy details.  Use the cmake_policy command to set the policy and
+  suppress this warning.
++
+  The target name "foobar" is unknown in this context.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)
+This warning is for project developers.  Use -Wno-dev to suppress it.

Tests/RunCMake/CMP0040/CMP0040-WARN-missing-target.cmake

@@ -0,0 +1,4 @@
+
+add_custom_command(TARGET foobar PRE_BUILD
+  COMMAND "${CMAKE_COMMAND} -E hello world"
+)

Tests/RunCMake/CMP0040/CMakeLists.txt

@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 2.8.12)
+project(${RunCMake_TEST} CXX)
+include(${RunCMake_TEST}.cmake NO_POLICY_SCOPE)

Tests/RunCMake/CMP0040/RunCMakeTest.cmake

@@ -0,0 +1,8 @@
+include(RunCMake)
+
+run_cmake(CMP0040-OLD-missing-target)
+run_cmake(CMP0040-NEW-missing-target)
+run_cmake(CMP0040-WARN-missing-target)
+
+run_cmake(CMP0040-OLD-existing-target)
+run_cmake(CMP0040-NEW-existing-target)

Tests/RunCMake/CMP0040/empty.cpp

@@ -0,0 +1,7 @@
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int empty()
+{
+  return 0;
+}

Tests/RunCMake/CMakeLists.txt

@@ -59,6 +59,7 @@ add_RunCMake_test(CMP0028)
 add_RunCMake_test(CMP0037)
 add_RunCMake_test(CMP0038)
 add_RunCMake_test(CMP0039)
+add_RunCMake_test(CMP0040)
 add_RunCMake_test(CTest)
 if(UNIX AND "${CMAKE_TEST_GENERATOR}" MATCHES "Unix Makefiles")
   add_RunCMake_test(CompilerChange)