Add policy CMP0040 to disallow custom commands on missing targets

1 files changed, 16 insertions, 0 deletions

diff --git a/Help/policy/CMP0040.rst b/Help/policy/CMP0040.rst
new file mode 100644
index 0000000000..99b54ff31d
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+++ b/Help/policy/CMP0040.rst
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+CMP0040
+-------
+
+The target in the TARGET signature of add_custom_command() must exist.
+
+CMake 2.8.12 and lower silently ignored a custom command created with
+the TARGET signature of :command:`add_custom_command`
+if the target is unknown.
+
+The OLD behavior for this policy is to ignore custom commands
+for unknown targets. The NEW behavior for this policy is to report and error
+if the target referenced in :command:`add_custom_command` is unknown.
+
+This policy was introduced in CMake version 3.0.0.  CMake version
+|release| warns when the policy is not set and uses OLD behavior.  Use
+the cmake_policy command to set it to OLD or NEW explicitly.