grub2: source /etc/default/grub.d/*.cfg after /etc/default/grub

[liweidong1722]

Previously only /etc/default/grub was sourced, ignoring fragments in /etc/default/grub.d. This patch sources all *.cfg files after the main grub file, allowing configuration fragments to override defaults.

[openshift-ci]

Hi @liweidong1722. Thanks for your PR.

I'm waiting for a ostreedev member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[gemini-code-assist]

Code Review

This pull request updates the grub2 boot script to source configuration fragments from /etc/default/grub.d/*.cfg after the main /etc/default/grub file. This allows for more modular configuration and overrides. The implementation is straightforward, but I've suggested a minor improvement to make it more robust by ensuring only regular files are sourced, preventing potential errors if a directory or special file matches the pattern.

[gemini-code-assist]

To make the script more robust, it's better to check if $f is a regular file using [ -f "$f" ] instead of just checking for existence with [ -e "$f" ]. This prevents the script from attempting to source a directory or other special file that happens to end with .cfg, which would result in an error.

Suggested change

	[ -e "$f" ] && . "$f"
	[ -f "$f" ] && . "$f"