RFR: 8352645: Add tool support to check order of includes

[Stefan Karlsson]

On Tue, 25 Mar 2025 21:19:03 GMT, Doug Simon <dnsimon at openjdk.org> wrote:

> Thanks for all the comments so far.
> 
> First thing is that my tool does nothing about re-ordering block of conditional includes vs unconditional includes. I briefly looked into that but it gets very complicated, very quickly. That kind of re-ordering will have to continue to be done manually or someone is going to have to invest significant time in enhancing/replacing the tool I wrote.

Yup. The extra effort needed to get the tool fully solve this is the reason why we haven't built a tool for this. There are a few scripts around but none is good enough to be promoted as *the* tool to correctly fix our includes.

It is still going to be a great tool for the devs.

> 
> Also, the tool tries to not change the number of lines in the original file. It should only add blank lines where necessary to separate user includes from sys includes. This explains some of the extra blank lines. For example, if the original was:
> 
> ```
> 1: #include "a.h"
> 2:
> 3: #include "b.h"
> 4:
> 5: #include <c.h>
> 6:
> 7: #include <d.h>
> ```
> 
> the output is:
> 
> ```
> 1: #include "a.h"
> 2: #include "b.h"
> 3:
> 4: #include <c.h>
> 5: #include <d.h>
> 6:
> 7:
> ```
> 
> Once again, I'd prefer to keep the tool simple and focused on the main task of ordering includes. Cleaning up extraneous blank lines can be done manually after running the tool.

OK. We'll just have to make sure to clean these out after having the initial run of this tool.

> 
> I'm currently working on converting `sort_includes.py` to `SortIncludes.java`. Once done, I'll open a second PR and limit changes to the C++ files I'm comfortable with changing and testing (namely in JVMCI directories). I will include a jtreg test to ensure these changes do not regress.
> 
> Follow up issues can then be opened for working on the remaining C++ files. The main point of this initial PR is to show that such a tool can be useful.

Sounds good to me.

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PR Comment: https://git.openjdk.org/jdk/pull/24180#issuecomment-2753413905