Fix efile_allocate for Mac

[indocomsoft]

https://bugs.erlang.org/browse/ERL-1042

[CLAassistant]

All committers have signed the CLA.

[jhogberg]

(Continuing the discussion from ERL-1042)

Should I keep the current behaviour on Linux?
Otherwise, I can standardise the behaviour to change the file size as well, in which case I will also change the Linux-specific part of the code to have mode be 0 instead of FALLOC_FL_KEEP_SIZE, and update the documentation

Yes, we don't like introducing behavioral changes in patches but it should be changed on master later on as we strive to have the same behavior on all platforms. It should've been this way to begin with in my opinion.

Can you squash and rebase the fix to maint, and expand the test in file_SUITE to verify that the file size is updated? We can settle for only testing this on the platforms that we know update it at the moment.

[indocomsoft]

I am still trying to get the test to fail when I revert the fix.

[indocomsoft]

@jhogberg I think I'm finally able to get the test to fail when I revert the fix. This is my first time writing Erlang actually. I usually write in Elixir, so I'm not too sure about the test that I wrote in Erlang. Do let me know if there are things to be improved.

Also, should I squash everything into 1 commit?

[jhogberg]

The test looks good aside from a minor nit, and we'd prefer it to be in the same commit as the fix.

[indocomsoft]

Fixed! I also followed the other tests in calling flush() and then returning ok

[jhogberg]

Looks good, if all goes well I'll merge it after 22.1 is released later this week. :)

[indocomsoft]

Great! Looking forward to the 22.1 release.

Should I also create a PR to change the Linux behaviour based off master after this PR is merged?

[jhogberg]

Should I also create a PR to change the Linux behaviour based off master after this PR is merged?

Feel free!

[jhogberg]

Merged, thanks again for the PR!