On Mon, Jan 31, 2022 at 10:01 AM Derrick Stolee via GitGitGadget
<gitgitgadget@xxxxxxxxx> wrote:
> The previous change added repo_config_set_worktree_gently() to assist
> writing config values into the config.worktree file, if enabled. An
> earlier change added init_worktree_config() as a helper to initialize
> extensions.worktreeConfig if not already enabled.
>
> Let the sparse-checkout builtin use these helpers instead of attempting to
> initialize the worktree config on its own. This changes behavior of 'git
> sparse-checkout set' in a few important ways:
>
> 1. Git will no longer upgrade the repository format, since this is not
> a requirement for understanding extensions.worktreeConfig.
>
> 2. If the main worktree is bare, then this command will not put the
> worktree in a broken state.
Although the three of four of us involved in this discussion
understand what "broken state" means, such a description may be too
vague for future readers. To help them out, perhaps we can do a better
job of conveying the nature of the actual breakage by rewriting all of
the above like this:
`git sparse-checkout set/init` enables worktree-specific
configuration[*] by setting extensions.worktreeConfig=true, but
neglects to perform the additional necessary bookkeeping of
relocating `core.bare=true` and `core.worktree` from
$GIT_COMMON_DIR/config to $GIT_COMMON_DIR/config.worktree, as
documented in git-worktree.txt. As a result of this oversight,
these settings, which are nonsensical for secondary worktrees, can
cause Git commands to incorrectly consider a worktree bare (in the
case of `core.bare`) or operate on the wrong worktree (in the case
of `core.worktree`). Fix this problem by taking advantage of the
recently-added init_worktree_config() which enables
`extensions.worktreeConfig` and takes care of necessary
bookkeeping.
While at it, for backward-compatibility reasons, also stop
upgrading the repository format to "1" since doing so is
(unintentionally) not required to take advantage of
`extensions.worktreeConfig`, as explained by 11664196ac ("Revert
"check_repository_format_gently(): refuse extensions for old
repositories"", 2020-07-15).
> The main reason to use worktree-specific config for the sparse-checkout
> builtin was to avoid enabling sparse-checkout patterns in one and
> causing a loss of files in another. If a worktree does not have a
> sparse-checkout patterns file, then the sparse-checkout logic will not
> kick in on that worktree.
Perhaps this paragraph can become the "[*]" footnote I referenced in
the above rewrite.
> Reported-by: Sean Allred <allred.sean@xxxxxxxxx>
> Helped-by: Eric Sunshine <sunshine@xxxxxxxxxxxxxx>
> Signed-off-by: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
