Improve Assert output

petere · petere · commit d78d452bc5ac · 2019-08-17T12:50:50.000+02:00
If an assertion expression contained a macro, the failed assertion message would print the expanded macro, which is usually unhelpful and confusing. Restructure the Assert macros to not expand any macros when constructing the failure message. This also fixes that the existing output for Assert et al. shows the *inverted* condition, which is also confusing and not how assertions usually work. Discussion: https://www.postgresql.org/message-id/flat/6c68efe3-117a-dcc1-73d4-18ba1ec532e2%402ndquadrant.com
diff --git a/src/include/c.h b/src/include/c.h
@@ -755,7 +755,7 @@ typedef NameData *Name;
 #define Trap(condition, errorType) \
 	do { \
 		if (condition) \
-			ExceptionalCondition(CppAsString(condition), (errorType), \
+			ExceptionalCondition(#condition, (errorType), \
 								 __FILE__, __LINE__); \
 	} while (0)
 
@@ -768,20 +768,34 @@ typedef NameData *Name;
  */
 #define TrapMacro(condition, errorType) \
 	((bool) (! (condition) || \
-			 (ExceptionalCondition(CppAsString(condition), (errorType), \
+			 (ExceptionalCondition(#condition, (errorType), \
 								   __FILE__, __LINE__), 0)))
 
 #define Assert(condition) \
-		Trap(!(condition), "FailedAssertion")
+	do { \
+		if (!(condition)) \
+			ExceptionalCondition(#condition, "FailedAssertion", \
+								 __FILE__, __LINE__); \
+	} while (0)
 
 #define AssertMacro(condition) \
-		((void) TrapMacro(!(condition), "FailedAssertion"))
+	((void) ((condition) || \
+			 (ExceptionalCondition(#condition, "FailedAssertion", \
+								   __FILE__, __LINE__), 0)))
 
 #define AssertArg(condition) \
-		Trap(!(condition), "BadArgument")
+	do { \
+		if (!(condition)) \
+			ExceptionalCondition(#condition, "BadArgument", \
+								 __FILE__, __LINE__); \
+	} while (0)
 
 #define AssertState(condition) \
-		Trap(!(condition), "BadState")
+	do { \
+		if (!(condition)) \
+			ExceptionalCondition(#condition, "BadState", \
+								 __FILE__, __LINE__); \
+	} while (0)
 
 /*
  * Check that `ptr' is `bndr' aligned.
