Teaching GNUFile methods to follow symlinks

[pfuntner]

On Linux systems, if File.mode is used on a file that's a symlink, it will return 0x777 because that's the mode of the symlink but mode is pretty meaningless for a symlink. By doing stat -L ... the command will automatically resolve symlinks.

I know there is the BSDFile implementation too but I don't believe I have access to a BSD system to try things out.

This addresses a problem where testinfra is used to get information on a target file but you don't want to worry about whether a symbolic link is involved - it's irrelevant. There are examples of symlinks in the Amazon Linux 2023 container:

$ docker run -it --rm amazonlinux:2023 Unable to find image 'amazonlinux:2023' locally 2023: Pulling from library/amazonlinux 1db371c0a72a: Pull complete Digest: sha256:355f1638075375e4db3a0f7aa9cd73f79fb1a738b72035bc66a3cfda30e0053b Status: Downloaded newer image for amazonlinux:2023 bash-5.2# ls -ld /etc/issue lrwxrwxrwx 1 root root 16 Dec 13 00:00 /etc/issue -> ../usr/lib/issue bash-5.2# stat /etc/issue File: /etc/issue -> ../usr/lib/issue Size: 16 Blocks: 0 IO Block: 4096 symbolic link Device: 37h/55d Inode: 4903000 Links: 1 Access: (0777/lrwxrwxrwx) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2023-12-13 00:00:03.000000000 +0000 Modify: 2023-12-13 00:00:03.000000000 +0000 Change: 2023-12-20 11:54:00.744190148 +0000 Birth: 2023-12-20 11:54:00.744190148 +0000 bash-5.2# stat -c %a /etc/issue 777 bash-5.2# ls -Lld /etc/issue -rw-r--r-- 1 root root 28 Dec 13 00:00 /etc/issue bash-5.2# stat -L /etc/issue File: /etc/issue Size: 28 Blocks: 8 IO Block: 4096 regular file Device: 37h/55d Inode: 4904219 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2023-12-13 00:00:03.000000000 +0000 Modify: 2023-12-13 00:00:03.000000000 +0000 Change: 2023-12-20 11:54:00.992194752 +0000 Birth: 2023-12-20 11:54:00.992194752 +0000 bash-5.2# stat -Lc %a /etc/issue 644 bash-5.2# 

I ran the tests via tox and they all passed.

This is my first pytest-testinfra pull request and I would be happy to rework it however it needs to be done.

[philpep]

Merged, thanks for this!