assert: allow non-int returning functions to assertethomson/assert_macros

Include GIT_ASSERT_WITH_RETVAL and GIT_ASSERT_ARG_WITH_RETVAL so that
functions that do not return int (or more precisely, where `-1` would
not be an error code) can assert.

This allows functions that return, eg, NULL on an error code to do that
by passing the return value (in this example, `NULL`) as a second
parameter to the GIT_ASSERT_WITH_RETVAL functions.

1 files changed, 21 insertions, 14 deletions

diff --git a/src/assert_safe.h b/src/assert_safe.h
index 9f2e16493..8c261100f 100644
--- a/src/assert_safe.h
+++ b/src/assert_safe.h
@@ -21,28 +21,35 @@
 
 # define GIT_ASSERT(expr) assert(expr)
 # define GIT_ASSERT_ARG(expr) assert(expr)
+
+# define GIT_ASSERT_WITH_RETVAL(expr, fail) assert(expr)
+# define GIT_ASSERT_ARG_WITH_RETVAL(expr, fail) assert(expr)
 #else
 
+/** Internal consistency check to stop the function. */
+# define GIT_ASSERT(expr) GIT_ASSERT_WITH_RETVAL(expr, -1)
+
 /**
  * Assert that a consumer-provided argument is valid, setting an
  * actionable error message and returning -1 if it is not.
  */
-# define GIT_ASSERT_ARG(expr) do { \
-		if (!(expr)) { \
-			git_error_set(GIT_ERROR_INVALID, \
-				"invalid argument: '%s'", \
-				#expr); \
-			return -1; \
-		} \
-	} while(0)
+# define GIT_ASSERT_ARG(expr) GIT_ASSERT_ARG_WITH_RETVAL(expr, -1)
+
+/** Internal consistency check to return the `fail` param on failure. */
+# define GIT_ASSERT_WITH_RETVAL(expr, fail) \
+	GIT_ASSERT__WITH_RETVAL(expr, GIT_ERROR_INTERNAL, "unrecoverable internal error", fail)
+
+/**
+ * Assert that a consumer-provided argument is valid, setting an
+ * actionable error message and returning the `fail` param if not.
+ */
+# define GIT_ASSERT_ARG_WITH_RETVAL(expr, fail) \
+	GIT_ASSERT__WITH_RETVAL(expr, GIT_ERROR_INVALID, "invalid argument", fail)
 
-/* Internal consistency check to stop the function. */
-# define GIT_ASSERT(expr) do { \
+# define GIT_ASSERT__WITH_RETVAL(expr, code, msg, fail) do { \
 		if (!(expr)) { \
-			git_error_set(GIT_ERROR_INTERNAL, \
-				"unrecoverable internal error: '%s'", \
-				#expr); \
-			return -1; \
+			git_error_set(code, "%s: '%s'", msg, #expr); \
+			return fail; \
 		} \
 	} while(0)