[PATCH 1/3] git-compat-util: introduce BUG_IF_NOT() macro

["Elijah Newren via GitGitGadget" <gitgitgadget@gmail.com>]

From: Elijah Newren <newren@gmail.com>

Create a BUG_IF_NOT() macro which is similar to assert(), but will not be
compiled out when NDEBUG is defined, and is thus safe to use even if its
argument has side-effects.

We will use this new macro in a subsequent commit to convert a few
existing assert() invocations to BUG_IF_NOT().  In particular, we'll
convert the handful of invocations which cannot be proven to be free of
side effects with a simple compiler/linker hack.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 git-compat-util.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/git-compat-util.h b/git-compat-util.h
index e123288e8f1..c3415ad7e0a 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -1460,6 +1460,7 @@ extern int bug_called_must_BUG;
 __attribute__((format (printf, 3, 4))) NORETURN
 void BUG_fl(const char *file, int line, const char *fmt, ...);
 #define BUG(...) BUG_fl(__FILE__, __LINE__, __VA_ARGS__)
+#define BUG_IF_NOT(a) if (!(a)) BUG("Assertion `" #a "' failed.")
 __attribute__((format (printf, 3, 4)))
 void bug_fl(const char *file, int line, const char *fmt, ...);
 #define bug(...) bug_fl(__FILE__, __LINE__, __VA_ARGS__)
-- 
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