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Notes |
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(0006063)
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Alex Neundorf
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2007-01-02 12:24
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That's similar to how all other scripting languages I know work.
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(0010678)
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Philip Lowman
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2008-03-01 14:32
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Here's a patch for implementing this (although it needs testing in Windows and on other platforms to squash any remaining internal CMake-generated warnings).
I modified cmCommandArgumentParserHelper.cxx so that when variables are expanded a warning is issued if the variable does not exist. This behavior can be overridden in two ways:
1. The user may set CMAKE_ALLOW_UNKNOWN_VARIABLE_READ_ACCESS which will suppress all warnings (this variable would presumably be set by CMAKE_BACKWARDS_COMPATABILITY)
2. The user may dereference variables with a special key (right now it's ALLOWUNDEF) to indicate that they are ok with the idea that the variable may be undefined and that no warning need be emitted.
SET(foo $ALLOWUNDEF{bar})
There are several core CMake core modules that are designed to use variables that are often left undefined. An example is CMakeCommonLanguageInclude.cmake which optionally uses a lot of "_INIT" type variables to populate the cache. Instead of wrapping all of these cache assignments with annoying conditionals the $ALLOWUNDEF keyword was added here.
Assuming that this is a feature that is still desired, some work would remain:
1. Trying out initial CMake configuration on a variety of platforms, hunting down warnings and either fixing the code not to dereference undefined variables or adding the ALLOWUNDEF keyword.
2. Having a look at the standard CMake modules and either add checks for the existence of external variables before dereferencing them or add the ALLOWUNDEF keyword.
3. Make the CMAKE_BACKWARDS_COMPATABILITY variable define CMAKE_ALLOW_UNKNOWN_VARIABLE_READ_ACCESS for <= 2.4
4. Add documentation on $ALLOWUNDEF{} somewhere |
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(0038083)
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Stephen Kelly
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2015-02-26 14:08
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This isn't going to happen. Might as well close it. |
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(0039072)
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Robert Maynard
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2015-07-08 08:57
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Closing resolved issues that have not been updated in more than 4 months. |
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undefined_variable_warnings.diff (21,243) 2008-03-01 14:34