Poison cmake.org 'nightly' branchnightly

We will no longer maintain this branch.  Poison it with an error
message that points clients to the gitlab.kitware.com repository.

1 files changed, 8 insertions, 0 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 545177b6e4..f36b3a1022 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,3 +1,11 @@
+message(FATAL_ERROR
+  "The cmake.org repository branch 'nightly' is no longer maintained.\n"
+  "Please see\n"
+  "  https://gitlab.kitware.com/cmake/cmake/blob/master/Help/dev/testing.rst\n"
+  "for instructions to set up integration testing builds that follow the "
+  "gitlab.kitware.com repository."
+  )
+
 # Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
 # file Copyright.txt or https://cmake.org/licensing for details.