Re: [GSoC][PATCH v7 06/10] dir-iterator: add flags parameter to dir_iterator_begin

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi Matheus,

On Tue, 18 Jun 2019, Matheus Tavares wrote:

>[...]
> +/*
> + * Look for a recursive symlink at iter->base.path pointing to any directory on
> + * the previous stack levels. If it is found, return 1. If not, return 0.
> + */
> +static int find_recursive_symlinks(struct dir_iterator_int *iter)
> +{
> +	int i;
> +
> +	if (!(iter->flags & DIR_ITERATOR_FOLLOW_SYMLINKS) ||
> +	    !S_ISDIR(iter->base.st.st_mode))
> +		return 0;
>
> +	for (i = 0; i < iter->levels_nr; ++i)
> +		if (iter->base.st.st_ino == iter->levels[i].ino)

This does not work on Windows. Remember, Git relies on (too) many areas
where Linux is strong, and the `lstat()` call is one of them. Therefore,
Git overuses that call.

In the Git for Windows project, we struggled a bit to emulate it in the
best way.

It is pretty expensive, for example, to find out the number of hard
links, the device ID, an equivalent of the inode, etc. Many `lstat()`
calls are really only interested in the `mtime`, though, meaning that we
would waste a ton of time if we tried to be more faithful in our `lstat()`
emulation.

Therefore, we simply assign `0` as inode.

Sure, this violates the POSIX standard, but imagine this: the FAT
filesystem (which is still in use!) does not have _anything_ resembling
inodes.

I fear, therefore, that we will require at least a workaround for the
situation where `st_ino` is always zero.

Ciao,
Johannes