https://github.com/git/git
Revision 5843080c85ae9d13f77442bec7bbec8e84a18100 authored by Junio C Hamano on 02 March 2023, 16:44:16 UTC, committed by Johannes Schindelin on 22 March 2023, 16:58:29 UTC
In http.c, the run_active_slot() function allows the given "slot" to
make progress by calling step_active_slots() in a loop repeatedly,
and the loop is not left until the request held in the slot
completes.

Ages ago, we used to use the slot->in_use member to get out of the
loop, which misbehaved when the request in "slot" completes (at
which time, the result of the request is copied away from the slot,
and the in_use member is cleared, making the slot ready to be
reused), and the "slot" gets reused to service a different request
(at which time, the "slot" becomes in_use again, even though it is
for a different request).  The loop terminating condition mistakenly
thought that the original request has yet to be completed.

Today's code, after baa7b67d (HTTP slot reuse fixes, 2006-03-10)
fixed this issue, uses a separate "slot->finished" member that is
set in run_active_slot() to point to an on-stack variable, and the
code that completes the request in finish_active_slot() clears the
on-stack variable via the pointer to signal that the particular
request held by the slot has completed.  It also clears the in_use
member (as before that fix), so that the slot itself can safely be
reused for an unrelated request.

One thing that is not quite clean in this arrangement is that,
unless the slot gets reused, at which point the finished member is
reset to NULL, the member keeps the value of &finished, which
becomes a dangling pointer into the stack when run_active_slot()
returns.  Clear the finished member before the control leaves the
function, which has a side effect of unconfusing compilers like
recent GCC 12 that is over-eager to warn against such an assignment.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 321854a
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Tip revision: 5843080c85ae9d13f77442bec7bbec8e84a18100 authored by Junio C Hamano on 02 March 2023, 16:44:16 UTC
http.c: clear the 'finished' member once we are done with it
Tip revision: 5843080
branch.h
#ifndef BRANCH_H
#define BRANCH_H

struct repository;
struct strbuf;

enum branch_track {
	BRANCH_TRACK_UNSPECIFIED = -1,
	BRANCH_TRACK_NEVER = 0,
	BRANCH_TRACK_REMOTE,
	BRANCH_TRACK_ALWAYS,
	BRANCH_TRACK_EXPLICIT,
	BRANCH_TRACK_OVERRIDE
};

extern enum branch_track git_branch_track;

/* Functions for acting on the information about branches. */

/*
 * Creates a new branch, where:
 *
 *   - r is the repository to add a branch to
 *
 *   - name is the new branch name
 *
 *   - start_name is the name of the existing branch that the new branch should
 *     start from
 *
 *   - force enables overwriting an existing (non-head) branch
 *
 *   - clobber_head_ok allows the currently checked out (hence existing)
 *     branch to be overwritten; without 'force', it has no effect.
 *
 *   - reflog creates a reflog for the branch
 *
 *   - quiet suppresses tracking information
 *
 *   - track causes the new branch to be configured to merge the remote branch
 *     that start_name is a tracking branch for (if any).
 *
 */
void create_branch(struct repository *r,
		   const char *name, const char *start_name,
		   int force, int clobber_head_ok,
		   int reflog, int quiet, enum branch_track track);

/*
 * Check if 'name' can be a valid name for a branch; die otherwise.
 * Return 1 if the named branch already exists; return 0 otherwise.
 * Fill ref with the full refname for the branch.
 */
int validate_branchname(const char *name, struct strbuf *ref);

/*
 * 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.
 * Return 1 if the named branch already exists; return 0 otherwise.
 * Fill ref with the full refname for the branch.
 */
int validate_new_branchname(const char *name, struct strbuf *ref, int force);

/*
 * Remove information about the merge state on the current
 * branch. (E.g., MERGE_HEAD)
 */
void remove_merge_branch_state(struct repository *r);

/*
 * Remove information about the state of working on the current
 * branch. (E.g., MERGE_HEAD)
 */
void remove_branch_state(struct repository *r, int verbose);

/*
 * Configure local branch "local" as downstream to branch "remote"
 * from remote "origin".  Used by git branch --set-upstream.
 * Returns 0 on success.
 */
#define BRANCH_CONFIG_VERBOSE 01
int install_branch_config(int flag, const char *local, const char *origin, const char *remote);

/*
 * Read branch description
 */
int read_branch_desc(struct strbuf *, const char *branch_name);

/*
 * Check if a branch is checked out in the main worktree or any linked
 * worktree and die (with a message describing its checkout location) if
 * it is.
 */
void die_if_checked_out(const char *branch, int ignore_current_worktree);

/*
 * Update all per-worktree HEADs pointing at the old ref to point the new ref.
 * This will be used when renaming a branch. Returns 0 if successful, non-zero
 * otherwise.
 */
int replace_each_worktree_head_symref(const char *oldref, const char *newref,
				      const char *logmsg);

#endif
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