Re: [CMake] Policy Stack within Macros/Functions

[Kyle Edwards via CMake]

On Mon, 2019-10-21 at 21:39 +0200, Sérgio Agostinho wrote:
> For further users with the same problem, you likely do not need need
> to invoke cmake_policy(PUSH)/cmake_policy(POP) from your shipped
> Config file, so just delete them and set whatever policies you need
> without concerns.

This has the caveat that CMP0011 must be set to NEW for it to work
(which should be the case with any sane project - CMP0011 was
introduced in 2.6, the oldest version recognized by
cmake_minimum_required().)

Kyle
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Re: [CMake] Policy Stack within Macros/Functions

[Sérgio Agostinho]

Thank you for the tip. After rereading the documentation again, I
noticed the following quote in the docs

CMake also manages a new entry for scripts loaded by include()

and find_package()


commands except when invoked with the NO_POLICY_SCOPE option (see
also policy CMP0011
).

Config files are invoked as a result from |find_package()| calls and
indeed, as the documentation states, it automatically creates a new
entry in the stack.

For further users with the same problem, you likely do not need need to
invoke |cmake_policy(PUSH)|/|cmake_policy(POP)| from your shipped Config
file, so just delete them and set whatever policies you need without
concerns.

Sérgio

On 21/10/19 15:45, Kyle Edwards wrote:

> On Sun, 2019-10-20 at 19:25 +0200, Sérgio Agostinho wrote:
>> Hey everyone,
>>
>> I’m shipping a config file for my library and inside I set push/pop
>> specific policies so that me and the consumers of my library can
>> target different policies without us clashing against each other.
>> However I’m struggling with cmake_policy(PUSH)/cmake_policy(POP) once
>> they are invoked from macro/functions.
>>
>> Here’s a minimal failure example illustrating my problem
>>
>>
>> project(pcl-config-test)
>> cmake_minimum_required(VERSION 3.5)
>>
>> cmake_policy(PUSH)
>>
>> macro(return_early)
>>   # clean up code
>>   cmake_policy(POP)
>>   return()
>> endmacro()
>>
>> # 1. do a bunch of things. invoke a couple of macros/functions
>> # from within other macros/functions, etc...
>>
>> # 2. some error occurs
>> if(ERROR)
>>   return_early()
>> endif()
>>
>> # 3. Everything went well
>> cmake_policy(POP)
>> This produces the following output
>>
>>
>> CMake Error at CMakeLists.txt:27 (my_macro):
>>   cmake_policy POP without matching PUSH
>>
>> CMake Error in CMakeLists.txt:
>>   cmake_policy PUSH without matching POP
>>
>> -- Configuring incomplete, errors occurred!
>> I was counting on the policy stack being preserved for at least
>> macros, but that is not the case.
>>
>> Is there a way for me to return early from my config file from within
>> macros?
> If you're trying to set policies within a function, set them at the
> module level rather than at the function level. The module-level policy
> settings will automatically be pushed when you call the function. That
> way, there will be no need to do cmake_policy(POP) within
> return_early().
>
> Kyle

​


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Re: [CMake] Policy Stack within Macros/Functions

[Kyle Edwards via CMake]

On Sun, 2019-10-20 at 19:25 +0200, Sérgio Agostinho wrote:
> Hey everyone,
> 
> I’m shipping a config file for my library and inside I set push/pop
> specific policies so that me and the consumers of my library can
> target different policies without us clashing against each other.
> However I’m struggling with cmake_policy(PUSH)/cmake_policy(POP) once
> they are invoked from macro/functions.
> 
> Here’s a minimal failure example illustrating my problem
> 
> 
> project(pcl-config-test)
> cmake_minimum_required(VERSION 3.5)
> 
> cmake_policy(PUSH)
> 
> macro(return_early)
>   # clean up code
>   cmake_policy(POP)
>   return()
> endmacro()
> 
> # 1. do a bunch of things. invoke a couple of macros/functions
> # from within other macros/functions, etc...
> 
> # 2. some error occurs
> if(ERROR)
>   return_early()
> endif()
> 
> # 3. Everything went well
> cmake_policy(POP)
> This produces the following output
> 
> 
> CMake Error at CMakeLists.txt:27 (my_macro):
>   cmake_policy POP without matching PUSH
> 
> CMake Error in CMakeLists.txt:
>   cmake_policy PUSH without matching POP
> 
> -- Configuring incomplete, errors occurred!
> I was counting on the policy stack being preserved for at least
> macros, but that is not the case.
> 
> Is there a way for me to return early from my config file from within
> macros?

If you're trying to set policies within a function, set them at the
module level rather than at the function level. The module-level policy
settings will automatically be pushed when you call the function. That
way, there will be no need to do cmake_policy(POP) within
return_early().

Kyle
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[CMake] Policy Stack within Macros/Functions

[Sérgio Agostinho]

Hey everyone,

I’m shipping a config file for my library and inside I set push/pop
specific policies so that me and the consumers of my library can target
different policies without us clashing against each other. However I’m
struggling with |cmake_policy(PUSH)|/|cmake_policy(POP)| once they are
invoked from macro/functions.

Here’s a minimal failure example illustrating my problem

|project(pcl-config-test) cmake_minimum_required(VERSION 3.5)
cmake_policy(PUSH) macro(return_early) # clean up code cmake_policy(POP)
return() endmacro() # 1. do a bunch of things. invoke a couple of
macros/functions # from within other macros/functions, etc... # 2. some
error occurs if(ERROR) return_early() endif() # 3. Everything went well
cmake_policy(POP) |

This produces the following output

|CMake Error at CMakeLists.txt:27 (my_macro): cmake_policy POP without
matching PUSH CMake Error in CMakeLists.txt: cmake_policy PUSH without
matching POP -- Configuring incomplete, errors occurred! |

I was counting on the policy stack being preserved for at least macros,
but that is not the case.

Is there a way for me to return early from my config file from within
macros?

Best regards,

Sérgio

​


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