From 0e9f62dab9fcce57279751bba47718d3f8baf3c8 Mon Sep 17 00:00:00 2001 From: Jeff King Date: Thu, 2 Mar 2017 03:23:01 -0500 Subject: interpret_branch_name: allow callers to restrict expansions The interpret_branch_name() function converts names like @{-1} and @{upstream} into branch names. The expanded ref names are not fully qualified, and may be outside of the refs/heads/ namespace (e.g., "@" expands to "HEAD", and "@{upstream}" is likely to be in "refs/remotes/"). This is OK for callers like dwim_ref() which are primarily interested in resolving the resulting name, no matter where it is. But callers like "git branch" treat the result as a branch name in refs/heads/. When we expand to a ref outside that namespace, the results are very confusing (e.g., "git branch @" tries to create refs/heads/HEAD, which is nonsense). Callers can't know from the returned string how the expansion happened (e.g., did the user really ask for a branch named "HEAD", or did we do a bogus expansion?). One fix would be to return some out-parameters describing the types of expansion that occurred. This has the benefit that the caller can generate precise error messages ("I understood @{upstream} to mean origin/master, but that is a remote tracking branch, so you cannot create it as a local name"). However, out-parameters make the function interface somewhat cumbersome. Instead, let's do the opposite: let the caller tell us which elements to expand. That's easier to pass in, and none of the callers give more precise error messages than "@{upstream} isn't a valid branch name" anyway (which should be sufficient). The strbuf_branchname() function needs a similar parameter, as most of the callers access interpret_branch_name() through it. We can break the callers down into two groups: 1. Callers that are happy with any kind of ref in the result. We pass "0" here, so they continue to work without restrictions. This includes merge_name(), the reflog handling in add_pending_object_with_path(), and substitute_branch_name(). This last is what powers dwim_ref(). 2. Callers that have funny corner cases (mostly in git-branch and git-checkout). These need to make use of the new parameter, but I've left them as "0" in this patch, and will address them individually in follow-on patches. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- cache.h | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'cache.h') diff --git a/cache.h b/cache.h index 81c59d4af4..7aea88534d 100644 --- a/cache.h +++ b/cache.h @@ -1312,8 +1312,17 @@ extern char *oid_to_hex(const struct object_id *oid); /* same static buffer as s * * If the input was ok but there are not N branch switches in the * reflog, it returns 0. - */ -extern int interpret_branch_name(const char *str, int len, struct strbuf *); + * + * If "allowed" is non-zero, it is a treated as a bitfield of allowable + * expansions: local branches ("refs/heads/"), remote branches + * ("refs/remotes/"), or "HEAD". If no "allowed" bits are set, any expansion is + * allowed, even ones to refs outside of those namespaces. + */ +#define INTERPRET_BRANCH_LOCAL (1<<0) +#define INTERPRET_BRANCH_REMOTE (1<<1) +#define INTERPRET_BRANCH_HEAD (1<<2) +extern int interpret_branch_name(const char *str, int len, struct strbuf *, + unsigned allowed); extern int get_oid_mb(const char *str, struct object_id *oid); extern int validate_headref(const char *ref); -- cgit v1.2.3