find_package: optionally resolve symlinks when discovering packages

Teach find_package() to resolve symlinks when constructing
relocatable prefix paths from discovered cmake config files.
The `CMAKE_FIND_PACKAGE_RESOLVE_SYMLINKS` variable enables
this behavior when set to `TRUE`.

Fixes: #18704

1 files changed, 10 insertions, 0 deletions

diff --git a/Source/cmFindPackageCommand.cxx b/Source/cmFindPackageCommand.cxx
index 8dc7ca2..2567b7a 100644
--- a/Source/cmFindPackageCommand.cxx
+++ b/Source/cmFindPackageCommand.cxx
@@ -95,6 +95,7 @@ cmFindPackageCommand::cmFindPackageCommand()
   this->UseLib32Paths = false;
   this->UseLib64Paths = false;
   this->UseLibx32Paths = false;
+  this->UseRealPath = false;
   this->PolicyScope = true;
   this->VersionMajor = 0;
   this->VersionMinor = 0;
@@ -195,6 +196,11 @@ bool cmFindPackageCommand::InitialPass(std::vector<std::string> const& args,
     this->NoSystemRegistry = true;
   }
 
+  // Check whether we should resolve symlinks when finding packages
+  if (this->Makefile->IsOn("CMAKE_FIND_PACKAGE_RESOLVE_SYMLINKS")) {
+    this->UseRealPath = true;
+  }
+
   // Check if Sorting should be enabled
   if (const char* so =
         this->Makefile->GetDefinition("CMAKE_FIND_PACKAGE_SORT_ORDER")) {
@@ -1502,6 +1508,10 @@ bool cmFindPackageCommand::FindConfigFile(std::string const& dir,
       fprintf(stderr, "Checking file [%s]\n", file.c_str());
     }
     if (cmSystemTools::FileExists(file, true) && this->CheckVersion(file)) {
+      // Allow resolving symlinks when the config file is found through a link
+      if (this->UseRealPath) {
+        file = cmSystemTools::GetRealPath(file);
+      }
       return true;
     }
   }