CMakePresets: Allow files included from CMakePresets.json to be anywhere

There are some valid use cases for allowing these files to be outside
the project directory. Relax the restriction, and include a strong
warning in the documentation.

Help/manual/cmake-presets.7.rst

@@ -37,10 +37,9 @@ 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`` must be inside the project
-directory. This restriction does not apply to ``CMakeUserPresets.json`` and
-files that it includes, unless those files are also included by
-``CMakePresets.json``.
+indirectly included from ``CMakePresets.json`` should be guaranteed to be
+provided by the project. ``CMakeUserPresets.json`` may include files from
+anywhere.
 
 Format
 ======

Source/cmCMakePresetsGraph.cxx

@@ -1014,8 +1014,6 @@ const char* cmCMakePresetsGraph::ResultToString(ReadFileResult result)
              "support.";
     case ReadFileResult::CYCLIC_INCLUDE:
       return "Cyclic include among preset files";
-    case ReadFileResult::INCLUDE_OUTSIDE_PROJECT:
-      return "File included from outside project directory";
   }
 
   return "Unknown error";

Source/cmCMakePresetsGraph.h

@@ -44,7 +44,6 @@ public:
     CONDITION_UNSUPPORTED,
     TOOLCHAIN_FILE_UNSUPPORTED,
     CYCLIC_INCLUDE,
-    INCLUDE_OUTSIDE_PROJECT,
   };
 
   enum class ArchToolsetStrategy

Source/cmCMakePresetsGraphReadJSON.cxx

@@ -424,17 +424,6 @@ cmCMakePresetsGraph::ReadFileResult cmCMakePresetsGraph::ReadJSONFile(
 {
   ReadFileResult result;
 
-  if (rootType == RootType::Project) {
-    auto normalizedFilename = cmSystemTools::CollapseFullPath(filename);
-
-    auto normalizedProjectDir =
-      cmSystemTools::CollapseFullPath(this->SourceDir);
-    if (!cmSystemTools::IsSubDirectory(normalizedFilename,
-                                       normalizedProjectDir)) {
-      return ReadFileResult::INCLUDE_OUTSIDE_PROJECT;
-    }
-  }
-
   for (auto const& f : this->Files) {
     if (cmSystemTools::SameFile(filename, f->Filename)) {
       file = f.get();
@@ -444,21 +433,6 @@ cmCMakePresetsGraph::ReadFileResult cmCMakePresetsGraph::ReadJSONFile(
         return cmCMakePresetsGraph::ReadFileResult::CYCLIC_INCLUDE;
       }
 
-      // Check files included by this file again to make sure they're in the
-      // project directory.
-      if (rootType == RootType::Project) {
-        for (auto* f2 : file->ReachableFiles) {
-          if (!cmSystemTools::SameFile(filename, f2->Filename)) {
-            File* file2;
-            if ((result = this->ReadJSONFile(
-                   f2->Filename, rootType, ReadReason::Included,
-                   inProgressFiles, file2)) != ReadFileResult::READ_OK) {
-              return result;
-            }
-          }
-        }
-      }
-
       return cmCMakePresetsGraph::ReadFileResult::READ_OK;
     }
   }

Tests/RunCMake/CMakePresets/IncludeOutsideProject-result.txt

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

Tests/RunCMake/CMakePresets/IncludeOutsideProject-stderr.txt

@@ -1,2 +0,0 @@
-^CMake Error: Could not read presets from [^
-]*/Tests/RunCMake/CMakePresets/IncludeOutsideProject: File included from outside project directory$