Subject: Re: [PATCH] fsck: detect bare repos in trees and warn

From: Junio C Hamano <[email-masked]>
Date: Thu, 07 Apr 2022 08:20:37 -0700

Glen Choo <[email-masked]> writes:

> @@ -602,6 +605,12 @@ static int fsck_tree(const struct object_id *tree_oid,
>  		has_dotdot |= !strcmp(name, "..");
>  		has_dotgit |= is_hfs_dotgit(name) || is_ntfs_dotgit(name);
>  		has_zero_pad |= *(char *)desc.buffer == '0';
> +		has_head |= !strcasecmp(name, "HEAD")
> +			&& (S_ISLNK(mode) || S_ISREG(mode));
> +		has_refs_entry |= !strcasecmp(name, "refs")
> +			&& (S_ISLNK(mode) || S_ISDIR(mode));

Sorry, I know I am to blame, but I think it is wrong to insist
"refs" (and others) to be a directory.  setup.c::is_git_directory()
only checks with access(X_OK).  Also, if I am not mistaken, we plan
to take advantage of it and may make refs a regular file, for
example, to signal that the ref-files backend is unwelcome in the
repository.  HEAD can be a symbolic link, not necessarily a regular
file.  We do not create "refs" and "objects" as symbolic links
ourselves, but it is good to see that the code protects us against
such a directory with these entries being one.

> +		has_objects_entry |= !strcasecmp(name, "objects")
> +			&& (S_ISLNK(mode) || S_ISDIR(mode));
>  
>  		if (is_hfs_dotgitmodules(name) || is_ntfs_dotgitmodules(name)) {
>  			if (!S_ISLNK(mode))
> @@ -739,6 +748,16 @@ static int fsck_tree(const struct object_id *tree_oid,
>  		retval += report(options, tree_oid, OBJ_TREE,
>  				 FSCK_MSG_TREE_NOT_SORTED,
>  				 "not properly sorted");
> +	/*
> +	 * Determine if this tree looks like a bare repository according
> +	 * to the rules of setup.c. If those are changed, this should be
> +	 * changed too.
> +	 */
> +	if (has_head && has_refs_entry && has_objects_entry)
> +		retval += report(options, tree_oid, OBJ_TREE,
> +				 FSCK_MSG_EMBEDDED_BARE_REPO,
> +				 "contains bare repository");
> +
>  	return retval;
>  }