[ClangFormat] Adjusting Include Order for Main Headers by Prefix Match

[thirumurugan-git]

Does the IncludeIsMainRegex option in the Clang format file only search for the suffix in the header stem? Is there an option to check the header prefix to identify it as "not a main file"? For example, consider the following code:

// file: a.cc
#include "b.h"
#include "../a.h"

// some code

When formatting this, a.h is prioritized as 0 (default) and always appears first. However, I want it to be placed last. Does Clang-Format support any option in the .clang-format file to address this, or would I need to use clang-off for the include section?

Note: The include must retain the relative path. Alternate approaches are not feasible. Could such an option be introduced in the future?"

[llvmbot]

@llvm/issue-subscribers-clang-format

Author: thirumurugan (thirumurugan-git)

Does the `IncludeIsMainRegex` option in the Clang format file only search for the suffix in the header stem? Is there an option to check the header prefix to identify it as "not a main file"? For example, consider the following code:

// file: a.cc
#include "b.h"
#include "../a.h"

// some code

When formatting this, a.h is prioritized as 0 (default) and always appears first. However, I want it to be placed last. Does Clang-Format support any option in the .clang-format file to address this, or would I need to use clang-off for the include section?

Note: The include must retain the relative path. Alternate approaches are not feasible. Could such an option be introduced in the future?"

[owenca]

You can insert an empty line between the two includes:

$ cat foo.cpp
// file: a.cc
#include "b.h"

#include "../a.h"

// some code
$ clang-format foo.cpp | diff foo.cpp -
$ 

[thirumurugan-git]

@owenca Sorry for the delay. I have the following .clang-format configuration:

IncludeBlocks: Regroup
IncludeCategories:
    - Regex:           '^<.*\.h>'
      Priority:        1
    - Regex:           '^<.*'
      Priority:        2
    - Regex:           '^[a-zA-Z].*'
      Priority:        3
    - Regex:           '\.\.\/.*'
      Priority:        4

I want to regroup all headers based on their priority, but I need the relative path headers to be placed in the last group. Is this possible? By default, headers with the same stem as the current file are assigned a priority of 0. However, with IncludeBlocks: Regroup, I can't seem to reorder the relative path headers to appear last in my case.

[owenca]

IncludeBlocks: Regroup
IncludeCategories:
    - Regex:           '^<.*\.h>'
      Priority:        1
    - Regex:           '^<.*'
      Priority:        2
    - Regex:           '^[a-zA-Z].*'

This doesn't match "b.h", which gets the lowest priority INT_MAX.

I want to regroup all headers based on their priority, but I need the relative path headers to be placed in the last group. Is this possible? By default, headers with the same stem as the current file are assigned a priority of 0. However, with IncludeBlocks: Regroup, I can't seem to reorder the relative path headers to appear last in my case.

You can't only if the stem a in ../a.h matches that of the filename a.cc.