Re: [PATCH] refs: forbid clang to complain about unreachable code
- From
Patrick Steinhardt <ps@pks.im>
- Date
- Oct 10, 2025, 05:34 UTC
- Message-ID
- <aOia55_sjFQjw1UQ@pks.im>
- In-Reply-To
- <pull.1984.git.1759995982220.gitgitgadget@gmail.com>
On Thu, Oct 09, 2025 at 07:46:22AM +0000, Johannes Schindelin via GitGitGadget wrote:
Show 17 quoted lines
> diff --git a/refs/files-backend.c b/refs/files-backend.c > index 088b52c740..814decf323 100644 > --- a/refs/files-backend.c > +++ b/refs/files-backend.c > @@ -3186,7 +3186,13 @@ static int files_transaction_finish(struct ref_store *ref_store, > * next update. If not, we try and create a regular symref. > */ > if (update->new_target && refs->prefer_symlink_refs) > - if (!create_ref_symlink(lock, update->new_target)) > + /* > + * By using the `NOT_CONSTANT()` trick, we can avoid > + * errors by `clang`'s `-Wunreachable` logic that would > + * report that the `continue` statement is not reachable > + * when `NO_SYMLINK_HEAD` is `#define`d. > + */ > + if (NOT_CONSTANT(!create_ref_symlink(lock, update->new_target))) > continue;
An alternative could be to fix this at the source, e.g. like the below (untested) patch. But I don't mind this too much, especially given that this here is the only callsite of that function anyway. So please feel free to disregard.
Thanks!
Patrick
diff --git a/refs/files-backend.c b/refs/files-backend.c index bb2bec3807..cb402a2a54 100644 --- a/refs/files-backend.c +++ b/refs/files-backend.c @@ -2115,7 +2115,7 @@ static int commit_ref_update(struct files_ref_store *refs, } #ifdef NO_SYMLINK_HEAD -#define create_ref_symlink(a, b) (-1) +#define create_ref_symlink(a, b) NOT_CONSTANT(-1) #else static int create_ref_symlink(struct ref_lock *lock, const char *target) {