Re: [PATCH 2/2] setup: Don't dereference in-tree symlinks for absolute paths

> The prefix_path_gently() function currently applies real_path to
> everything if given an absolute path, dereferencing symlinks both
> outside and inside the work tree. In order to manipulate symliks in the
> work tree using absolute paths, symlinks should only be dereferenced
> outside the work tree.
> 
> Modify prefix_path_gently() to first normalize the path in order to
> make sure path levels are separated by '/', then use this separator to
> check the real path of each level of the path until it has found the
> length that corresponds to the work tree.
> 
> For absolute paths, the function did not, nor does now do, any actual
> prefixing, hence we simply remove the path corresponding to the work
> tree and return the remaining in-tree part of the path.
> 
> Fixes t0060-82.
> 
> Signed-off-by: Martin Erik Werner <martinerikwerner@gmail.com>
> ---
>  setup.c               | 54 ++++++++++++++++++++++++++++++++-------------------
>  t/t0060-path-utils.sh |  2 +-
>  2 files changed, 35 insertions(+), 21 deletions(-)
> 
> diff --git a/setup.c b/setup.c
> index 6c3f85f..bec587e 100644
> --- a/setup.c
> +++ b/setup.c
> @@ -22,11 +22,41 @@ char *prefix_path_gently(const char *prefix, int len,
>  	const char *orig = path;
>  	char *sanitized;
>  	if (is_absolute_path(orig)) {
> -		const char *temp = real_path(path);
> -		sanitized = xmalloc(len + strlen(temp) + 1);
> -		strcpy(sanitized, temp);
> +		char npath[strlen(path)];

>  		if (remaining_prefix)
>  			*remaining_prefix = 0;
> +		if (normalize_path_copy_len(npath, path, remaining_prefix))
> +			return NULL;
> +		const char *work_tree = get_git_work_tree();