7 files changed, 45 insertions, 11 deletions
diff --git a/Source/cmCMakeMinimumRequired.cxx b/Source/cmCMakeMinimumRequired.cxx
index c4834a8..2b51976 100644
--- a/Source/cmCMakeMinimumRequired.cxx
+++ b/Source/cmCMakeMinimumRequired.cxx
@@ -42,7 +42,7 @@ bool cmCMakeMinimumRequired::InitialPass(std::vector<std::string> const& args,
 
   // Make sure there was a version to check.
   if (version_string.empty()) {
-    return this->EnforceUnknownArguments();
+    return this->EnforceUnknownArguments(std::string());
   }
 
   // Separate the <min> version and any trailing ...<max> component.
@@ -102,7 +102,7 @@ bool cmCMakeMinimumRequired::InitialPass(std::vector<std::string> const& args,
   }
 
   // The version is not from the future, so enforce unknown arguments.
-  if (!this->EnforceUnknownArguments()) {
+  if (!this->EnforceUnknownArguments(version_max)) {
     return false;
   }
 
@@ -118,14 +118,39 @@ bool cmCMakeMinimumRequired::InitialPass(std::vector<std::string> const& args,
   return true;
 }
 
-bool cmCMakeMinimumRequired::EnforceUnknownArguments()
+bool cmCMakeMinimumRequired::EnforceUnknownArguments(
+  std::string const& version_max)
 {
-  if (!this->UnknownArguments.empty()) {
-    std::ostringstream e;
-    e << "called with unknown argument \"" << this->UnknownArguments[0]
-      << "\".";
-    this->SetError(e.str());
-    return false;
+  if (this->UnknownArguments.empty()) {
+    return true;
   }
-  return true;
+
+  // Consider the max version if at least two components were given.
+  unsigned int max_major = 0;
+  unsigned int max_minor = 0;
+  unsigned int max_patch = 0;
+  unsigned int max_tweak = 0;
+  if (sscanf(version_max.c_str(), "%u.%u.%u.%u", &max_major, &max_minor,
+             &max_patch, &max_tweak) >= 2) {
+    unsigned int current_major = cmVersion::GetMajorVersion();
+    unsigned int current_minor = cmVersion::GetMinorVersion();
+    unsigned int current_patch = cmVersion::GetPatchVersion();
+    unsigned int current_tweak = cmVersion::GetTweakVersion();
+
+    if ((current_major < max_major) ||
+        (current_major == max_major && current_minor < max_minor) ||
+        (current_major == max_major && current_minor == max_minor &&
+         current_patch < max_patch) ||
+        (current_major == max_major && current_minor == max_minor &&
+         current_patch == max_patch && current_tweak < max_tweak)) {
+      // A ...<max> version was given that is larger than the current
+      // version of CMake, so tolerate unknown arguments.
+      return true;
+    }
+  }
+
+  std::ostringstream e;
+  e << "called with unknown argument \"" << this->UnknownArguments[0] << "\".";
+  this->SetError(e.str());
+  return false;
 }
diff --git a/Source/cmCMakeMinimumRequired.h b/Source/cmCMakeMinimumRequired.h
index 18d9460..f9b61e1 100644
--- a/Source/cmCMakeMinimumRequired.h
+++ b/Source/cmCMakeMinimumRequired.h
@@ -34,7 +34,7 @@ public:
 
 private:
   std::vector<std::string> UnknownArguments;
-  bool EnforceUnknownArguments();
+  bool EnforceUnknownArguments(std::string const& version_max);
 };
 
 #endif
diff --git a/Tests/RunCMake/cmake_minimum_required/Future.cmake b/Tests/RunCMake/cmake_minimum_required/Future.cmake
new file mode 100644
index 0000000..2b5c445
--- /dev/null
+++ b/Tests/RunCMake/cmake_minimum_required/Future.cmake
@@ -0,0 +1 @@
+cmake_minimum_required(VERSION 3.11...99.0 SOME_FUTURE_OPTION)
diff --git a/Tests/RunCMake/cmake_minimum_required/RunCMakeTest.cmake b/Tests/RunCMake/cmake_minimum_required/RunCMakeTest.cmake
index 22aa5b7..1030211 100644
--- a/Tests/RunCMake/cmake_minimum_required/RunCMakeTest.cmake
+++ b/Tests/RunCMake/cmake_minimum_required/RunCMakeTest.cmake
@@ -2,6 +2,8 @@ include(RunCMake)
 
 run_cmake(Before24)
 run_cmake(CompatBefore24)
+run_cmake(Future)
 run_cmake(PolicyBefore24)
 run_cmake(Range)
 run_cmake(RangeBad)
+run_cmake(Unknown)
diff --git a/Tests/RunCMake/cmake_minimum_required/Unknown-result.txt b/Tests/RunCMake/cmake_minimum_required/Unknown-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/cmake_minimum_required/Unknown-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/cmake_minimum_required/Unknown-stderr.txt b/Tests/RunCMake/cmake_minimum_required/Unknown-stderr.txt
new file mode 100644
index 0000000..d698642
--- /dev/null
+++ b/Tests/RunCMake/cmake_minimum_required/Unknown-stderr.txt
@@ -0,0 +1,4 @@
+^CMake Error at Unknown.cmake:1 \(cmake_minimum_required\):
+  cmake_minimum_required called with unknown argument "SOME_UNKNOWN_OPTION".
+Call Stack \(most recent call first\):
+  CMakeLists.txt:[0-9]+ \(include\)$
diff --git a/Tests/RunCMake/cmake_minimum_required/Unknown.cmake b/Tests/RunCMake/cmake_minimum_required/Unknown.cmake
new file mode 100644
index 0000000..6c70f91
--- /dev/null
+++ b/Tests/RunCMake/cmake_minimum_required/Unknown.cmake
@@ -0,0 +1 @@
+cmake_minimum_required(VERSION 3.11 SOME_UNKNOWN_OPTION)