[PATCH 3/6] remote: check branch->merge before access in branch_release

From: Jacob Keller <jacob.keller@gmail.com>

The branch_release function doesn't check the merge field before accessing it, based on an assumption that merge will be set if branch->merge_nr is non-zero.

This is not always the case. It turns out that branch->merge is not initialized until set_merge() is called, but branch->merge_nr can be non-zero from handle_config() calling add_merge().

set_merge() is not called until branch_get(). This function does set merge_nr to zero if merge is not initialized. However, branch_release is called on every branch when tearing down a repository.

An upcoming change to submodule--helper will initialize the remote state by calling read_config(). In some cases, this results in branches in the remote_state which have a non-zero merge_nr but no merge array. This results in a crash when tearing the repository down.

To fix this, lets simply check if merge is valid before attempting to release its contents.

This makes it safe to initialize the remote_state for a submodule repository without crashing on teardown.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
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 remote.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)