From c5c714ecb6bb103a31158ab2cacf20e6731ec46d Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Wed, 4 Jun 2025 16:17:45 +0200 Subject: [PATCH] refs: forbid clang to complain about unreachable code When `NO_SYMLINK_HEAD` is defined, `create_ref_symlink()` is hard-coded as `(-1)`, and as a consequence the condition `!create_ref_symlink()` always evaluates to false, rendering any code guarded by that condition unreachable. Therefore, clang is _technically_ correct when it complains about unreachable code. It does completely miss the fact that this is okay because on _other_ platforms, where `NO_SYMLINK_HEAD` is not defined, the code isn't unreachable at all. Let's use the same trick as in 82e79c63642c (git-compat-util: add NOT_CONSTANT macro and use it in atfork_prepare(), 2025-03-17) to appease clang while at the same time keeping the `-Wunreachable` flag to potentially find _actually_ unreachable code. Signed-off-by: Johannes Schindelin --- refs/files-backend.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/refs/files-backend.c b/refs/files-backend.c index 088b52c740b9ff..814decf323e14d 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; if (update->flags & REF_NEEDS_COMMIT) {