[ci][c++] fixed build/header_guard errors from cpplint

[StrikerRUS]

Refer to #7002.

I believe this linting rule is quite important because it helps to catch things like

include/LightGBM/cuda/cuda_rocm_interop.h:0:  No #ifndef header guard found, suggested CPP variable is: INCLUDE_LIGHTGBM_CUDA_CUDA_ROCM_INTEROP_H_  [build/header_guard] [5]

[borchero]

In line with the INCLUDE_ definitions, shouldn't this be

Suggested change

	#ifndef SRC_NETWORK_LINKERS_H_
	#define SRC_NETWORK_LINKERS_H_
	#ifndef SRC_LIGHTGBM_NETWORK_LINKERS_H_
	#define SRC_LIGHTGBM_NETWORK_LINKERS_H_

[StrikerRUS]

cpplint expects exactly these variables...
E.g.

...
src/treelearner/gpu_tree_learner.h:5:  #ifndef header guard has wrong style, please use: SRC_TREELEARNER_GPU_TREE_LEARNER_H_  [build/header_guard] [5]
src/treelearner/gpu_tree_learner.h:287:  #endif line should be "#endif  // SRC_TREELEARNER_GPU_TREE_LEARNER_H_"  [build/header_guard] [5]
...
include/LightGBM/utils/random.h:5:  #ifndef header guard has wrong style, please use: INCLUDE_LIGHTGBM_UTILS_RANDOM_H_  [build/header_guard] [5]
include/LightGBM/utils/random.h:117:  #endif line should be "#endif  // INCLUDE_LIGHTGBM_UTILS_RANDOM_H_"  [build/header_guard] [5]

[borchero]

I see, thanks for the explanation!

[jameslamb]

To clarify this... cpplint is just translating the directory structure into these identifiers. This file is at src/network/, not src/LightGBM/network/.

[jameslamb]

Wait actually, before we merge... I thought about this more and realized that not having LIGHTGBM_ or similar in the name increases the risk of conflicts with definitions from other projects.

@StrikerRUS could you try the suggestion from cpplint/cpplint#44 (comment), to see if it'd result in cpplint being OK with everything prefixed with LIGHTGBM_?

[jameslamb]

Fine with me! I just recently spent time typing out a review comment on a PR about this (#7039 (comment)), I'm happy to have a linter catch it automatically instead.

[jameslamb]

Sorry, just thought about this and I'm worried that generic names like SRC_APPLICATION_PREDICTOR_HPP_ could risk conflicting with other projects.