From: Phillip Wood Date: Tue, 14 Jun 2022 10:09:15 GMT Subject: Re: [PATCH 1/4] branch: add branch_checked_out() helper Message-ID: <42ada1a3-adc2-2c43-9aa1-7854858865ae@gmail.com> In-Reply-To: Hi Stolee On 08/06/2022 21:08, Derrick Stolee via GitGitGadget wrote: > From: Derrick Stolee > > The validate_new_branchname() method contains a check to see if a branch > is checked out in any non-bare worktree. This is intended to prevent a > force push that will mess up an existing checkout. This helper is not > suitable to performing just that check, because the method will die() > when the branch is checked out instead of returning an error code. > > Create a new branch_checked_out() helper that performs the most basic > form of this check. To ensure we can call branch_checked_out() in a loop > with good performance, do a single preparation step that iterates over > all worktrees and stores their current HEAD branches in a strmap. The > branch_checked_out() helper can then discover these branches using a > hash lookup. > > This helper is currently missing some key functionality. Namely: it > doesn't look for active rebases or bisects which mean that the branch is > "checked out" even though HEAD doesn't point to that ref. This > functionality will be added in a coming change. > > We could use branch_checked_out() in validate_new_branchname(), but this > missing functionality would be a regression. However, we have no tests > that cover this case! > > Add a new test script that will be expanded with these cross-worktree > ref updates. The current tests would still pass if we refactored > validate_new_branchname() to use this version of branch_checked_out(). > The next change will fix that functionality and add the proper test > coverage. > > Signed-off-by: Derrick Stolee > --- > branch.c | 42 +++++++++++++++++++++++++++++++++++++++ > branch.h | 8 ++++++++ > t/t2407-worktree-heads.sh | 24 ++++++++++++++++++++++ > 3 files changed, 74 insertions(+) > create mode 100755 t/t2407-worktree-heads.sh > > diff --git a/branch.c b/branch.c > index 2d6569b0c62..061a11f3415 100644 > --- a/branch.c > +++ b/branch.c > @@ -10,6 +10,7 @@ > #include "worktree.h" > #include "submodule-config.h" > #include "run-command.h" > +#include "strmap.h" > > struct tracking { > struct refspec_item spec; > @@ -369,6 +370,47 @@ int validate_branchname(const char *name, struct strbuf *ref) > return ref_exists(ref->buf); > } > > +static int initialized_checked_out_branches; > +static struct strmap current_checked_out_branches = STRMAP_INIT; I looks like this map is never freed which I think makes sense but makes me wonder about the relevance of patch 5. I think it would probably be worth marking the map with UNLEAK() in prepare_checked_out_branches(). > +static void prepare_checked_out_branches(void) > +{ > + int i = 0; > + struct worktree **worktrees; > + > + if (initialized_checked_out_branches) > + return; > + initialized_checked_out_branches = 1; > + > + worktrees = get_worktrees(); > + > + while (worktrees[i]) { > + struct worktree *wt = worktrees[i++]; > + > + if (wt->is_bare) > + continue; > + > + if (wt->head_ref) > + strmap_put(¤t_checked_out_branches, > + wt->head_ref, > + xstrdup(wt->path)); STRMAP_INIT sets .strdup_strings = 1, so the xstrdup() is unnecessary. > + } > + > + free_worktrees(worktrees); > +} > + > +int branch_checked_out(const char *refname, char **path) > +{ > + const char *path_in_set; > + prepare_checked_out_branches(); > + > + path_in_set = strmap_get(¤t_checked_out_branches, refname); > + if (path_in_set && path) > + *path = xstrdup(path_in_set); > + > + return !!path_in_set; > +} I like the idea of having a specific function to see if a branch is checkout out rather than Ævar's suggestion of forcing all callers to do strmap_get(get_worktree_refs_strmap(), ref) which will quickly get tiresome. I do wonder though if we'd be better off with a thin wrapper around strmap_get() such as const char* branch_checked_out(const char *refname) { prepare_checked_out_branches(); return strmap_get(¤t_checked_out_branches, refname); } so that the user can choose whether to copy the path or not. Best Wishes Phillip > /* > * Check if a branch 'name' can be created as a new branch; die otherwise. > * 'force' can be used when it is OK for the named branch already exists. > diff --git a/branch.h b/branch.h > index 560b6b96a8f..5ea93d217b1 100644 > --- a/branch.h > +++ b/branch.h > @@ -101,6 +101,14 @@ void create_branches_recursively(struct repository *r, const char *name, > const char *tracking_name, int force, > int reflog, int quiet, enum branch_track track, > int dry_run); > + > +/* > + * Returns true if the branch at 'refname' is checked out at any > + * non-bare worktree. The path of the worktree is stored in the > + * given 'path', if provided. > + */ > +int branch_checked_out(const char *refname, char **path); > + > /* > * Check if 'name' can be a valid name for a branch; die otherwise. > * Return 1 if the named branch already exists; return 0 otherwise. > diff --git a/t/t2407-worktree-heads.sh b/t/t2407-worktree-heads.sh > new file mode 100755 > index 00000000000..dd905dc1a5c > --- /dev/null > +++ b/t/t2407-worktree-heads.sh > @@ -0,0 +1,24 @@ > +#!/bin/sh > + > +test_description='test operations trying to overwrite refs at worktree HEAD' > + > +. ./test-lib.sh > + > +test_expect_success 'setup' ' > + for i in 1 2 3 4 > + do > + test_commit $i && > + git branch wt-$i && > + git worktree add wt-$i wt-$i || return 1 > + done > +' > + > +test_expect_success 'refuse to overwrite: checked out in worktree' ' > + for i in 1 2 3 4 > + do > + test_must_fail git branch -f wt-$i HEAD 2>err > + grep "cannot force update the branch" err || return 1 > + done > +' > + > +test_done