add_custom_command: Disallow exe-suffixed targets in DEPENDS

Two targets whose names differ only in a `.exe` suffix create a
conflict when adding target- and file-level dependencies for a custom
command. Add CMP0212 to provide compatibility with the old behavior.

Issue: #27612

Help/command/add_custom_command.rst

@@ -188,6 +188,12 @@ Generating Files
        cause the custom command to re-run whenever the target is
        recompiled.
 
+       .. versionchanged:: 4.4
+
+         Previously an executable target could be specified using the name
+         of the target with ``.exe`` appended.  This is no longer allowed.
+         See policy :policy:`CMP0212`.
+
     2. If the argument is an absolute path, a file-level dependency
        is created on that path.
 

Help/manual/cmake-policies.7.rst

@@ -100,6 +100,7 @@ Policies Introduced by CMake 4.4
 .. toctree::
    :maxdepth: 1
 
+   CMP0212: add_custom_command DEPENDS does not strip .exe suffixes. </policy/CMP0212>
    CMP0211: A file may belong to at most one file set in a target. </policy/CMP0211>
 
 Policies Introduced by CMake 4.3

Help/policy/CMP0212.rst

@@ -0,0 +1,31 @@
+CMP0212
+-------
+
+.. versionadded:: 4.4
+
+:command:`add_custom_command` ``DEPENDS`` does not strip ``.exe`` suffixes.
+
+When searching for dependencies specified with the ``DEPENDS`` option of
+:command:`add_custom_command`, CMake 4.3 and below applied a heuristic to
+remove ``.exe`` from the end of ``DEPENDS`` argument values, which created a
+target-level dependency on an executable with that stripped name if such a
+target exists. This allowed using the name of the target output file as an
+alternative spelling when naming dependencies. However, with the emergence of
+CMake's target model, specifying the output file in this way is no longer
+needed, and leads to conflicts in creating target- and file-level dependencies
+when targets exist with the ``.exe`` suffix in the name itself.
+
+The ``OLD`` behavior of this policy strips the ``.exe`` suffix from arguments
+to ``DEPENDS`` when searching for target-level dependencies. The ``NEW``
+behavior does not strip the ``.exe`` suffix in its search. CMake will otherwise
+proceed normally with the other dependency search heuristics as specified in
+:command:`add_custom_command` ``DEPENDS``. Users are encouraged to specify the
+name of the executable target if a target-level dependency is desired, or use
+the :genex:`TARGET_FILE` generator expression if a file-level dependency
+is desired, rather than implying the target indirectly via its output file name.
+
+.. |INTRODUCED_IN_CMAKE_VERSION| replace:: 4.4
+.. |WARNS_OR_DOES_NOT_WARN| replace:: does *not* warn
+.. include:: include/STANDARD_ADVICE.rst
+
+.. include:: include/DEPRECATED.rst

Help/release/dev/add_custom_command-DEPENDS-exe.rst

@@ -0,0 +1,6 @@
+add_custom_command-DEPENDS-exe
+------------------------------
+
+* Names of executables given to the ``DEPENDS`` argument of
+  :command:`add_custom_command` no longer have ``.exe`` suffixes stripped to
+  establish target-level dependencies. See policy :policy:`CMP0212`.

Source/cmFastbuildTargetGenerator.cxx

@@ -356,7 +356,8 @@ void cmFastbuildTargetGenerator::GetDepends(
   for (auto dep : ccg.GetDepends()) {
     LogMessage("Dep: " + dep);
     auto orig = dep;
-    if (this->LocalCommonGenerator->GetRealDependency(dep, Config, dep)) {
+    if (this->LocalCommonGenerator->GetRealDependency(
+          dep, Config, dep, ccg.GetCC().GetCMP0212Status())) {
       LogMessage("Real dep: " + dep);
       if (!dep.empty()) {
         LogMessage("Custom command real dep: " + dep);

Source/cmGlobalXCodeGenerator.cxx

@@ -2095,7 +2095,8 @@ cmXCodeObject* cmGlobalXCodeGenerator::CreateRunScriptBuildPhase(
     realDepends.reserve(ccg.GetDepends().size());
     for (auto const& d : ccg.GetDepends()) {
       std::string dep;
-      if (this->CurrentLocalGenerator->GetRealDependency(d, configName, dep)) {
+      if (this->CurrentLocalGenerator->GetRealDependency(
+            d, configName, dep, cc.GetCMP0212Status())) {
         realDepends.emplace_back(std::move(dep));
       }
     }
@@ -2464,7 +2465,8 @@ void cmGlobalXCodeGenerator::CreateCustomRulesMakefile(
     realDepends.reserve(ccg.GetDepends().size());
     for (auto const& d : ccg.GetDepends()) {
       std::string dep;
-      if (this->CurrentLocalGenerator->GetRealDependency(d, configName, dep)) {
+      if (this->CurrentLocalGenerator->GetRealDependency(
+            d, configName, dep, command.GetCMP0212Status())) {
         realDepends.emplace_back(std::move(dep));
       }
     }

Source/cmLocalGenerator.cxx

@@ -2317,7 +2317,8 @@ cmGeneratorTarget* cmLocalGenerator::FindGeneratorTargetToUse(
 
 bool cmLocalGenerator::GetRealDependency(std::string const& inName,
                                          std::string const& config,
-                                         std::string& dep)
+                                         std::string& dep,
+                                         cmPolicies::PolicyStatus cmp0212)
 {
   // Older CMake code may specify the dependency using the target
   // output file rather than the target name.  Such code would have
@@ -2334,8 +2335,8 @@ bool cmLocalGenerator::GetRealDependency(std::string const& inName,
 
   // Look for a CMake target with the given name.
   cmGeneratorTarget* target = this->FindGeneratorTargetToUse(name);
-  if (!target && cmHasSuffix(name, ".exe"_s)) {
-    // If it doesn't exist, try to strip the `.exe` suffix.
+  if (!target && cmHasSuffix(name, ".exe"_s) && cmp0212 != cmPolicies::NEW) {
+    // If it doesn't exist, try to strip the `.exe` suffix per CMP0212.
     std::string strippedName =
       cmSystemTools::GetFilenameWithoutLastExtension(name);
     if (cmGeneratorTarget* strippedTarget =

Source/cmLocalGenerator.h

@@ -310,7 +310,7 @@ public:
    *   used for dependencies of custom commands.
    */
   bool GetRealDependency(std::string const& name, std::string const& config,
-                         std::string& dep);
+                         std::string& dep, cmPolicies::PolicyStatus cmp0212);
 
   /** Called from command-line hook to clear dependencies.  */
   virtual void ClearDependencies(cmMakefile* /* mf */, bool /* verbose */) {}

Source/cmLocalNinjaGenerator.cxx

@@ -414,7 +414,8 @@ void cmLocalNinjaGenerator::AppendCustomCommandDeps(
 {
   for (std::string const& i : ccg.GetDepends()) {
     std::string dep;
-    if (this->GetRealDependency(i, config, dep)) {
+    if (this->GetRealDependency(i, config, dep,
+                                ccg.GetCC().GetCMP0212Status())) {
       ninjaDeps.push_back(
         this->GetGlobalNinjaGenerator()->ConvertToNinjaPath(dep));
     }

Source/cmLocalUnixMakefileGenerator3.cxx

@@ -957,7 +957,8 @@ void cmLocalUnixMakefileGenerator3::AppendCustomDepend(
   for (std::string const& d : ccg.GetDepends()) {
     // Lookup the real name of the dependency in case it is a CMake target.
     std::string dep;
-    if (this->GetRealDependency(d, this->GetConfigName(), dep)) {
+    if (this->GetRealDependency(d, this->GetConfigName(), dep,
+                                ccg.GetCC().GetCMP0212Status())) {
       depends.push_back(std::move(dep));
     }
   }

Source/cmLocalVisualStudio7Generator.cxx

@@ -1867,7 +1867,8 @@ void cmLocalVisualStudio7Generator::WriteCustomRule(
       for (std::string const& d : ccg.GetDepends()) {
         // Get the real name of the dependency in case it is a CMake target.
         std::string dep;
-        if (this->GetRealDependency(d, config, dep)) {
+        if (this->GetRealDependency(d, config, dep,
+                                    command.GetCMP0212Status())) {
           fout << this->ConvertToXMLOutputPath(dep) << ";";
         }
       }

Source/cmPolicies.h

@@ -632,6 +632,9 @@ class cmMakefile;
          3, 0, WARN)                                                          \
   SELECT(POLICY, CMP0211,                                                     \
          "A file may belong to at most one file set in a target.", 4, 4, 0,   \
+         WARN)                                                                \
+  SELECT(POLICY, CMP0212,                                                     \
+         "add_custom_command DEPENDS does not strip .exe suffixes.", 4, 4, 0, \
          WARN)
 
 #define CM_SELECT_ID(F, A1, A2, A3, A4, A5, A6) F(A1)
@@ -692,7 +695,8 @@ class cmMakefile;
 
 #define CM_FOR_EACH_CUSTOM_COMMAND_POLICY(F)                                  \
   F(CMP0116)                                                                  \
-  F(CMP0147)
+  F(CMP0147)                                                                  \
+  F(CMP0212)
 
 /** \class cmPolicies
  * \brief Handles changes in CMake behavior and policies

Source/cmVisualStudio10TargetGenerator.cxx

@@ -1840,7 +1840,7 @@ void cmVisualStudio10TargetGenerator::WriteCustomRule(
 
       for (std::string const& d : ccg.GetDepends()) {
         std::string dep;
-        if (lg->GetRealDependency(d, c, dep)) {
+        if (lg->GetRealDependency(d, c, dep, command.GetCMP0212Status())) {
           if (!unique_inputs.insert(dep).second) {
             // already listed
             continue;

Tests/RunCMake/CMP0212/CMP0212-NEW-build-result.txt

@@ -0,0 +1 @@
+[^0]

Tests/RunCMake/CMP0212/CMP0212-NEW-build-stdout.txt

@@ -0,0 +1 @@
+.*

Tests/RunCMake/CMP0212/CMP0212-common-exe.cmake

@@ -0,0 +1,2 @@
+add_executable(foo main.c)
+set_target_properties(foo PROPERTIES RUNTIME_OUTPUT_DIRECTORY bin)

Tests/RunCMake/CMP0212/CMakeLists.txt

@@ -0,0 +1,4 @@
+cmake_minimum_required(VERSION 4.3)
+project(${RunCMake_TEST} C)
+include(CMP0212-common-exe.cmake)
+add_subdirectory(subdir)

Tests/RunCMake/CMP0212/RunCMakeTest.cmake

@@ -0,0 +1,12 @@
+include(RunCMake)
+
+function(run_cmake_case_cmp0212 case)
+  set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/${case}-build)
+  run_cmake(${case})
+  set(RunCMake_TEST_NO_CLEAN 1)
+  set(RunCMake_TEST_OUTPUT_MERGE 1)
+  run_cmake_command(${case}-build ${CMAKE_COMMAND} --build . --target ${ARGN})
+endfunction()
+
+run_cmake_case_cmp0212(CMP0212-OLD tgt1)
+run_cmake_case_cmp0212(CMP0212-NEW tgt1 bar)

Tests/RunCMake/CMP0212/main.c

@@ -0,0 +1,4 @@
+int main()
+{
+  return 0;
+}

Tests/RunCMake/CMP0212/subdir/CMP0212-NEW.cmake

@@ -0,0 +1,11 @@
+cmake_policy(SET CMP0212 NEW)
+include(CMP0212-common-custom.cmake)
+
+# Define an executable with a different target name so that the above custom
+# command finds the file-level dependency instead of the target-level
+# dependency, and thus fails the build by compiling a bad C file.
+add_executable(bar bad.c)
+set_target_properties(bar PROPERTIES
+  RUNTIME_OUTPUT_DIRECTORY "$<1:${CMAKE_CURRENT_BINARY_DIR}>"
+  RUNTIME_OUTPUT_NAME foo
+)

Tests/RunCMake/CMP0212/subdir/CMP0212-OLD.cmake

@@ -0,0 +1,2 @@
+cmake_policy(SET CMP0212 OLD)
+include(CMP0212-common-custom.cmake)

Tests/RunCMake/CMP0212/subdir/CMP0212-common-custom.cmake

@@ -0,0 +1,6 @@
+add_custom_command(
+  OUTPUT cmd1
+  COMMAND ${CMAKE_COMMAND} -E touch "${CMAKE_CURRENT_BINARY_DIR}/cmd1"
+  DEPENDS foo.exe
+)
+add_custom_target(tgt1 DEPENDS cmd1)

Tests/RunCMake/CMP0212/subdir/CMakeLists.txt

@@ -0,0 +1 @@
+include(${RunCMake_TEST}.cmake)

Tests/RunCMake/CMP0212/subdir/bad.c

@@ -0,0 +1 @@
+#error "This is an invalid C file."

Tests/RunCMake/CMakeLists.txt

@@ -180,6 +180,9 @@ add_RunCMake_test(CMP0170)
 add_RunCMake_test(CMP0171)
 add_RunCMake_test(CMP0173)
 add_RunCMake_test(CMP0187)
+if(WIN32)
+  add_RunCMake_test(CMP0212)
+endif()
 
 if(CMAKE_C_COMPILER_ID STREQUAL "MSVC")
   add_RunCMake_test(CMP0194 -DCMAKE_C_COMPILER_VERSION=${CMAKE_C_COMPILER_VERSION})