16 files changed, 122 insertions, 65 deletions
diff --git a/Help/command/target_sources.rst b/Help/command/target_sources.rst
index f4833e7..e482117 100644
--- a/Help/command/target_sources.rst
+++ b/Help/command/target_sources.rst
@@ -75,7 +75,8 @@ Adds a file set to a target, or adds files to an existing file set. Targets
 have zero or more named file sets. Each file set has a name, a type, a scope of
 ``INTERFACE``, ``PUBLIC``, or ``PRIVATE``, one or more base directories, and
 files within those directories. The only acceptable type is ``HEADERS``. The
-optional default file sets are named after their type.
+optional default file sets are named after their type. The target may not be a
+custom target.
 
 Files in a ``PRIVATE`` or ``PUBLIC`` file set are marked as source files for
 the purposes of IDE integration. Additionally, files in ``HEADERS`` file sets
diff --git a/Help/manual/cmake-presets.7.rst b/Help/manual/cmake-presets.7.rst
index 69d0543..4620984 100644
--- a/Help/manual/cmake-presets.7.rst
+++ b/Help/manual/cmake-presets.7.rst
@@ -19,28 +19,16 @@ supports files included with the ``include`` field.
 
 ``CMakePresets.json`` and ``CMakeUserPresets.json`` live in the project's root
 directory. They both have exactly the same format, and both are optional
-(though at least one must be present if ``--preset`` is specified.)
-``CMakePresets.json`` is meant to save project-wide builds, while
-``CMakeUserPresets.json`` is meant for developers to save their own local
-builds. ``CMakePresets.json`` may be checked into a version control system, and
-``CMakeUserPresets.json`` should NOT be checked in. For example, if a project
-is using Git, ``CMakePresets.json`` may be tracked, and
+(though at least one must be present if ``--preset`` is specified).
+``CMakePresets.json`` is meant to specify project-wide build details, while
+``CMakeUserPresets.json`` is meant for developers to specify their own local
+build details.
+
+``CMakePresets.json`` may be checked into a version control system, and
+``CMakeUserPresets.json`` should NOT be checked in. For example, if a
+project is using Git, ``CMakePresets.json`` may be tracked, and
 ``CMakeUserPresets.json`` should be added to the ``.gitignore``.
 
-``CMakePresets.json`` and ``CMakeUserPresets.json`` can include other files
-with the ``include`` field in file version ``4`` and later. Files included by
-these files can also include other files. If a preset file contains presets
-that inherit from presets in another file, the file must include the other file
-either directly or indirectly. Include cycles are not allowed among files (if
-``a.json`` includes ``b.json``, ``b.json`` cannot include ``a.json``). However,
-a file may be included multiple times from the same file or from different
-files. If ``CMakePresets.json`` and ``CMakeUserPresets.json`` are both present,
-``CMakeUserPresets.json`` implicitly includes ``CMakePresets.json``, even with
-no ``include`` field, in all versions of the format. Files directly or
-indirectly included from ``CMakePresets.json`` should be guaranteed to be
-provided by the project. ``CMakeUserPresets.json`` may include files from
-anywhere.
-
 Format
 ======
 
@@ -73,6 +61,13 @@ The root object recognizes the following fields:
 
     An optional integer representing the patch version.
 
+``include``
+
+  An optional array of strings representing files to include. If the filenames
+  are not absolute, they are considered relative to the current file.
+  This is allowed in preset files specifying version ``4`` or above.
+  See `Includes`_ for discussion of the constraints on included files.
+
 ``vendor``
 
   An optional map containing vendor-specific information. CMake does not
@@ -97,11 +92,25 @@ The root object recognizes the following fields:
   An optional array of `Test Preset`_ objects.
   This is allowed in preset files specifying version ``2`` or above.
 
-``include``
+Includes
+^^^^^^^^
 
-  An optional array of strings representing files to include. If the filenames
-  are not absolute, they are considered relative to the current file.
-  This is allowed in preset files specifying version ``4`` or above.
+``CMakePresets.json`` and ``CMakeUserPresets.json`` can include other files
+with the ``include`` field in file version ``4`` and later. Files included
+by these files can also include other files. If ``CMakePresets.json`` and
+``CMakeUserPresets.json`` are both present, ``CMakeUserPresets.json``
+implicitly includes ``CMakePresets.json``, even with no ``include`` field,
+in all versions of the format.
+
+If a preset file contains presets that inherit from presets in another file,
+the file must include the other file either directly or indirectly.
+Include cycles are not allowed among files. If ``a.json`` includes
+``b.json``, ``b.json`` cannot include ``a.json``. However, a file may be
+included multiple times from the same file or from different files.
+
+Files directly or indirectly included from ``CMakePresets.json`` should be
+guaranteed to be provided by the project. ``CMakeUserPresets.json`` may
+include files from anywhere.
 
 Configure Preset
 ^^^^^^^^^^^^^^^^
@@ -129,16 +138,20 @@ that may contain the following fields:
 ``inherits``
 
   An optional array of strings representing the names of presets to inherit
-  from. The preset will inherit all of the fields from the ``inherits``
+  from. This field can also be a string, which is equivalent to an array
+  containing one string.
+
+  The preset will inherit all of the fields from the ``inherits``
   presets by default (except ``name``, ``hidden``, ``inherits``,
   ``description``, and ``displayName``), but can override them as
   desired. If multiple ``inherits`` presets provide conflicting values for
   the same field, the earlier preset in the ``inherits`` list will be
-  preferred. Presets in ``CMakePresets.json`` may not inherit from presets
-  in ``CMakeUserPresets.json``.
+  preferred.
 
-  This field can also be a string, which is equivalent to an array
-  containing one string.
+  A preset can only inherit from another preset that is defined in the
+  same file or in one of the files it includes (directly or indirectly).
+  Presets in ``CMakePresets.json`` may not inherit from presets in
+  ``CMakeUserPresets.json``.
 
 ``condition``
 
@@ -371,17 +384,21 @@ that may contain the following fields:
 
 ``inherits``
 
-  An optional array of strings representing the names of presets to
-  inherit from. The preset will inherit all of the fields from the
+  An optional array of strings representing the names of presets to inherit
+  from. This field can also be a string, which is equivalent to an array
+  containing one string.
+
+  The preset will inherit all of the fields from the
   ``inherits`` presets by default (except ``name``, ``hidden``,
   ``inherits``, ``description``, and ``displayName``), but can override
   them as desired. If multiple ``inherits`` presets provide conflicting
   values for the same field, the earlier preset in the ``inherits`` list
-  will be preferred. Presets in ``CMakePresets.json`` may not inherit from
-  presets in ``CMakeUserPresets.json``.
+  will be preferred.
 
-  This field can also be a string, which is equivalent to an array
-  containing one string.
+  A preset can only inherit from another preset that is defined in the
+  same file or in one of the files it includes (directly or indirectly).
+  Presets in ``CMakePresets.json`` may not inherit from presets in
+  ``CMakeUserPresets.json``.
 
 ``condition``
 
@@ -544,17 +561,21 @@ that may contain the following fields:
 
 ``inherits``
 
-  An optional array of strings representing the names of presets to
-  inherit from. The preset will inherit all of the fields from the
+  An optional array of strings representing the names of presets to inherit
+  from. This field can also be a string, which is equivalent to an array
+  containing one string.
+
+  The preset will inherit all of the fields from the
   ``inherits`` presets by default (except ``name``, ``hidden``,
   ``inherits``, ``description``, and ``displayName``), but can override
   them as desired. If multiple ``inherits`` presets provide conflicting
   values for the same field, the earlier preset in the ``inherits`` list
-  will be preferred. Presets in ``CMakePresets.json`` may not inherit from
-  presets in ``CMakeUserPresets.json``.
+  will be preferred.
 
-  This field can also be a string, which is equivalent to an array
-  containing one string.
+  A preset can only inherit from another preset that is defined in the
+  same file or in one of the files it includes (directly or indirectly).
+  Presets in ``CMakePresets.json`` may not inherit from presets in
+  ``CMakeUserPresets.json``.
 
 ``condition``
 
@@ -1004,7 +1025,8 @@ Recognized macros include:
 
 ``${sourceDir}``
 
-  Path to the project source directory.
+  Path to the project source directory (i.e. the same as
+  :variable:`CMAKE_SOURCE_DIR`).
 
 ``${sourceParentDir}``
 
diff --git a/Help/manual/presets/example.json b/Help/manual/presets/example.json
index a7ec10e..873c4ad 100644
--- a/Help/manual/presets/example.json
+++ b/Help/manual/presets/example.json
@@ -2,9 +2,13 @@
   "version": 4,
   "cmakeMinimumRequired": {
     "major": 3,
-    "minor": 21,
+    "minor": 23,
     "patch": 0
   },
+  "include": [
+    "otherThings.json",
+    "moreThings.json"
+  ],
   "configurePresets": [
     {
       "name": "default",
diff --git a/Help/prop_tgt/CROSSCOMPILING_EMULATOR.rst b/Help/prop_tgt/CROSSCOMPILING_EMULATOR.rst
index d7fb9b1..8b777e4 100644
--- a/Help/prop_tgt/CROSSCOMPILING_EMULATOR.rst
+++ b/Help/prop_tgt/CROSSCOMPILING_EMULATOR.rst
@@ -8,9 +8,10 @@ This command will be added as a prefix to :command:`add_test`,
 :command:`add_custom_command`, and :command:`add_custom_target` commands
 for built target system executables.
 
-If this property contains a :ref:`semicolon-separated list <CMake Language
-Lists>`, then the first value is the command and remaining values are its
-arguments.
+.. versionadded:: 3.15
+  If this property contains a :ref:`semicolon-separated list <CMake Language
+  Lists>`, then the first value is the command and remaining values are its
+  arguments.
 
 This property is initialized by the value of the
 :variable:`CMAKE_CROSSCOMPILING_EMULATOR` variable if it is set when a target
diff --git a/Help/variable/CMAKE_CROSSCOMPILING_EMULATOR.rst b/Help/variable/CMAKE_CROSSCOMPILING_EMULATOR.rst
index 815da00..e21b35d 100644
--- a/Help/variable/CMAKE_CROSSCOMPILING_EMULATOR.rst
+++ b/Help/variable/CMAKE_CROSSCOMPILING_EMULATOR.rst
@@ -7,9 +7,10 @@ This variable is only used when :variable:`CMAKE_CROSSCOMPILING` is on. It
 should point to a command on the host system that can run executable built
 for the target system.
 
-If this variable contains a :ref:`semicolon-separated list <CMake Language
-Lists>`, then the first value is the command and remaining values are its
-arguments.
+.. versionadded:: 3.15
+  If this variable contains a :ref:`semicolon-separated list <CMake Language
+  Lists>`, then the first value is the command and remaining values are its
+  arguments.
 
 The command will be used to run :command:`try_run` generated executables,
 which avoids manual population of the ``TryRunResults.cmake`` file.
diff --git a/Modules/FindThreads.cmake b/Modules/FindThreads.cmake
index 4198374..e4d6cf3 100644
--- a/Modules/FindThreads.cmake
+++ b/Modules/FindThreads.cmake
@@ -164,21 +164,18 @@ if(CMAKE_HAVE_PTHREAD_H)
     elseif(CMAKE_CXX_COMPILER_LOADED)
       CHECK_CXX_SOURCE_COMPILES("${PTHREAD_C_CXX_TEST_SOURCE}" CMAKE_HAVE_LIBC_PTHREAD)
     endif()
-
-    # Check for -pthread first if enabled. This is the recommended
-    # way, but not backwards compatible as one must also pass -pthread
-    # as compiler flag then.
-    if(THREADS_PREFER_PTHREAD_FLAG)
-      _check_pthreads_flag()
-    endif()
-
-    if(Threads_FOUND)
-      # do nothing, we are done
-    elseif(CMAKE_HAVE_LIBC_PTHREAD)
+    if(CMAKE_HAVE_LIBC_PTHREAD)
       set(CMAKE_THREAD_LIBS_INIT "")
       set(CMAKE_HAVE_THREADS_LIBRARY 1)
       set(Threads_FOUND TRUE)
     else()
+      # Check for -pthread first if enabled. This is the recommended
+      # way, but not backwards compatible as one must also pass -pthread
+      # as compiler flag then.
+      if (THREADS_PREFER_PTHREAD_FLAG)
+         _check_pthreads_flag()
+      endif ()
+
       if(CMAKE_SYSTEM MATCHES "GHS-MULTI")
         _check_threads_lib(posix pthread_create CMAKE_HAVE_PTHREADS_CREATE)
       endif()
diff --git a/Source/cmFindPathCommand.cxx b/Source/cmFindPathCommand.cxx
index a0a8570..27074ff 100644
--- a/Source/cmFindPathCommand.cxx
+++ b/Source/cmFindPathCommand.cxx
@@ -65,7 +65,8 @@ std::string cmFindPathCommand::FindHeader()
 }
 
 std::string cmFindPathCommand::FindHeaderInFramework(
-  std::string const& file, std::string const& dir) const
+  std::string const& file, std::string const& dir,
+  cmFindBaseDebugState& debug) const
 {
   std::string fileName = file;
   std::string frameWorkName;
@@ -88,11 +89,13 @@ std::string cmFindPathCommand::FindHeaderInFramework(
       std::string fpath = cmStrCat(dir, frameWorkName, ".framework");
       std::string intPath = cmStrCat(fpath, "/Headers/", fileName);
       if (cmSystemTools::FileExists(intPath)) {
+        debug.FoundAt(intPath);
         if (this->IncludeFileInPath) {
           return intPath;
         }
         return fpath;
       }
+      debug.FailedAt(intPath);
     }
   }
   // if it is not found yet or not a framework header, then do a glob search
@@ -103,12 +106,15 @@ std::string cmFindPathCommand::FindHeaderInFramework(
   std::vector<std::string> files = globIt.GetFiles();
   if (!files.empty()) {
     std::string fheader = cmSystemTools::CollapseFullPath(files[0]);
+    debug.FoundAt(fheader);
     if (this->IncludeFileInPath) {
       return fheader;
     }
     fheader.resize(fheader.size() - file.size());
     return fheader;
   }
+
+  // No frameworks matched the glob, so nothing more to add to debug.FailedAt()
   return "";
 }
 
@@ -135,8 +141,7 @@ std::string cmFindPathCommand::FindFrameworkHeader(cmFindBaseDebugState& debug)
 {
   for (std::string const& n : this->Names) {
     for (std::string const& sp : this->SearchPaths) {
-      std::string fwPath = this->FindHeaderInFramework(n, sp);
-      fwPath.empty() ? debug.FailedAt(fwPath) : debug.FoundAt(fwPath);
+      std::string fwPath = this->FindHeaderInFramework(n, sp, debug);
       if (!fwPath.empty()) {
         return fwPath;
       }
diff --git a/Source/cmFindPathCommand.h b/Source/cmFindPathCommand.h
index c7281f1..a7746f6 100644
--- a/Source/cmFindPathCommand.h
+++ b/Source/cmFindPathCommand.h
@@ -30,7 +30,8 @@ public:
 
 private:
   std::string FindHeaderInFramework(std::string const& file,
-                                    std::string const& dir) const;
+                                    std::string const& dir,
+                                    cmFindBaseDebugState& debug) const;
   std::string FindHeader();
   std::string FindNormalHeader(cmFindBaseDebugState& debug);
   std::string FindFrameworkHeader(cmFindBaseDebugState& debug);
diff --git a/Source/cmTargetSourcesCommand.cxx b/Source/cmTargetSourcesCommand.cxx
index 818e271..b425acb 100644
--- a/Source/cmTargetSourcesCommand.cxx
+++ b/Source/cmTargetSourcesCommand.cxx
@@ -16,6 +16,7 @@
 #include "cmMakefile.h"
 #include "cmMessageType.h"
 #include "cmPolicies.h"
+#include "cmStateTypes.h"
 #include "cmStringAlgorithms.h"
 #include "cmSystemTools.h"
 #include "cmTarget.h"
@@ -202,6 +203,11 @@ bool TargetSourcesImpl::HandleFileSetMode(
     return false;
   }
 
+  if (this->Target->GetType() == cmStateEnums::UTILITY) {
+    this->SetError("FILE_SETs may not be added to custom targets");
+    return false;
+  }
+
   bool const isDefault = args.Type == args.FileSet ||
     (args.Type.empty() && args.FileSet[0] >= 'A' && args.FileSet[0] <= 'Z');
   std::string type = isDefault ? args.FileSet : args.Type;
diff --git a/Tests/RunCMake/CMakePresets/RunCMakeTest.cmake b/Tests/RunCMake/CMakePresets/RunCMakeTest.cmake
index 51e786e..955cf53 100644
--- a/Tests/RunCMake/CMakePresets/RunCMakeTest.cmake
+++ b/Tests/RunCMake/CMakePresets/RunCMakeTest.cmake
@@ -372,4 +372,9 @@ if(CMAKE_HOST_WIN32)
 endif()
 file(WRITE "${RunCMake_BINARY_DIR}/example.json.in" "${_example}")
 set(CMakePresets_FILE "${RunCMake_BINARY_DIR}/example.json.in")
+set(CMakePresets_EXTRA_FILES
+  "${RunCMake_SOURCE_DIR}/otherThings.json.in"
+  "${RunCMake_SOURCE_DIR}/moreThings.json.in"
+)
 run_cmake_presets(DocumentationExample --preset=default)
+unset(CMakePresets_EXTRA_FILES)
diff --git a/Tests/RunCMake/CMakePresets/moreThings.json.in b/Tests/RunCMake/CMakePresets/moreThings.json.in
new file mode 100644
index 0000000..61a2092
--- /dev/null
+++ b/Tests/RunCMake/CMakePresets/moreThings.json.in
@@ -0,0 +1,3 @@
+{
+  "version": 1
+}
diff --git a/Tests/RunCMake/CMakePresets/otherThings.json.in b/Tests/RunCMake/CMakePresets/otherThings.json.in
new file mode 100644
index 0000000..61a2092
--- /dev/null
+++ b/Tests/RunCMake/CMakePresets/otherThings.json.in
@@ -0,0 +1,3 @@
+{
+  "version": 1
+}
diff --git a/Tests/RunCMake/target_sources/FileSetCustomTarget-result.txt b/Tests/RunCMake/target_sources/FileSetCustomTarget-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/target_sources/FileSetCustomTarget-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/target_sources/FileSetCustomTarget-stderr.txt b/Tests/RunCMake/target_sources/FileSetCustomTarget-stderr.txt
new file mode 100644
index 0000000..8ab3de7
--- /dev/null
+++ b/Tests/RunCMake/target_sources/FileSetCustomTarget-stderr.txt
@@ -0,0 +1,4 @@
+^CMake Error at FileSetCustomTarget\.cmake:[0-9]+ \(target_sources\):
+  target_sources FILE_SETs may not be added to custom targets
+Call Stack \(most recent call first\):
+  CMakeLists\.txt:[0-9]+ \(include\)$
diff --git a/Tests/RunCMake/target_sources/FileSetCustomTarget.cmake b/Tests/RunCMake/target_sources/FileSetCustomTarget.cmake
new file mode 100644
index 0000000..ce26400
--- /dev/null
+++ b/Tests/RunCMake/target_sources/FileSetCustomTarget.cmake
@@ -0,0 +1,2 @@
+add_custom_target(tgt)
+target_sources(tgt PRIVATE FILE_SET HEADERS FILES h1.h)
diff --git a/Tests/RunCMake/target_sources/RunCMakeTest.cmake b/Tests/RunCMake/target_sources/RunCMakeTest.cmake
index 171de60..da9944d 100644
--- a/Tests/RunCMake/target_sources/RunCMakeTest.cmake
+++ b/Tests/RunCMake/target_sources/RunCMakeTest.cmake
@@ -38,6 +38,7 @@ run_cmake(FileSetNoExistPrivate)
 run_cmake(FileSetNoExistInterface)
 run_cmake(FileSetNoExistInstall)
 run_cmake(FileSetDirectories)
+run_cmake(FileSetCustomTarget)
 
 set(RunCMake_TEST_OPTIONS -DCMAKE_POLICY_DEFAULT_CMP0115=NEW)
 run_cmake(FileSetFileNoExist)