Numeric error suppression in jsonpath

Add support of numeric error suppression to jsonpath as it's required by
standard.  This commit doesn't use PG_TRY()/PG_CATCH() in order to implement
that.  Instead, it provides internal versions of numeric functions used, which
support error suppression.

Discussion: https://postgr.es/m/fcc6fc6a-b497-f39a-923d-aa34d0c588e8%402ndQuadrant.com
Author: Alexander Korotkov, Nikita Glukhov
Reviewed-by: Tomas Vondra

1 files changed, 205 insertions, 47 deletions

diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c
index 0765f2cdb59..fbc2863622e 100644
--- a/src/backend/utils/adt/numeric.c
+++ b/src/backend/utils/adt/numeric.c
@@ -475,10 +475,11 @@ static char *get_str_from_var(const NumericVar *var);
 static char *get_str_from_var_sci(const NumericVar *var, int rscale);
 
 static Numeric make_result(const NumericVar *var);
+static Numeric make_result_opt_error(const NumericVar *var, bool *error);
 
 static void apply_typmod(NumericVar *var, int32 typmod);
 
-static int32 numericvar_to_int32(const NumericVar *var);
+static bool numericvar_to_int32(const NumericVar *var, int32 *result);
 static bool numericvar_to_int64(const NumericVar *var, int64 *result);
 static void int64_to_numericvar(int64 val, NumericVar *var);
 #ifdef HAVE_INT128
@@ -1558,7 +1559,10 @@ width_bucket_numeric(PG_FUNCTION_ARGS)
 	}
 
 	/* if result exceeds the range of a legal int4, we ereport here */
-	result = numericvar_to_int32(&result_var);
+	if (!numericvar_to_int32(&result_var, &result))
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("integer out of range")));
 
 	free_var(&count_var);
 	free_var(&result_var);
@@ -2406,6 +2410,23 @@ numeric_add(PG_FUNCTION_ARGS)
 {
 	Numeric		num1 = PG_GETARG_NUMERIC(0);
 	Numeric		num2 = PG_GETARG_NUMERIC(1);
+	Numeric		res;
+
+	res = numeric_add_opt_error(num1, num2, NULL);
+
+	PG_RETURN_NUMERIC(res);
+}
+
+/*
+ * numeric_add_opt_error() -
+ *
+ *	Internal version of numeric_add().  If "*have_error" flag is provided,
+ *	on error it's set to true, NULL returned.  This is helpful when caller
+ *	need to handle errors by itself.
+ */
+Numeric
+numeric_add_opt_error(Numeric num1, Numeric num2, bool *have_error)
+{
 	NumericVar	arg1;
 	NumericVar	arg2;
 	NumericVar	result;
@@ -2415,7 +2436,7 @@ numeric_add(PG_FUNCTION_ARGS)
 	 * Handle NaN
 	 */
 	if (NUMERIC_IS_NAN(num1) || NUMERIC_IS_NAN(num2))
-		PG_RETURN_NUMERIC(make_result(&const_nan));
+		return make_result(&const_nan);
 
 	/*
 	 * Unpack the values, let add_var() compute the result and return it.
@@ -2426,11 +2447,11 @@ numeric_add(PG_FUNCTION_ARGS)
 	init_var(&result);
 	add_var(&arg1, &arg2, &result);
 
-	res = make_result(&result);
+	res = make_result_opt_error(&result, have_error);
 
 	free_var(&result);
 
-	PG_RETURN_NUMERIC(res);
+	return res;
 }
 
 
@@ -2444,6 +2465,24 @@ numeric_sub(PG_FUNCTION_ARGS)
 {
 	Numeric		num1 = PG_GETARG_NUMERIC(0);
 	Numeric		num2 = PG_GETARG_NUMERIC(1);
+	Numeric		res;
+
+	res = numeric_sub_opt_error(num1, num2, NULL);
+
+	PG_RETURN_NUMERIC(res);
+}
+
+
+/*
+ * numeric_sub_opt_error() -
+ *
+ *	Internal version of numeric_sub().  If "*have_error" flag is provided,
+ *	on error it's set to true, NULL returned.  This is helpful when caller
+ *	need to handle errors by itself.
+ */
+Numeric
+numeric_sub_opt_error(Numeric num1, Numeric num2, bool *have_error)
+{
 	NumericVar	arg1;
 	NumericVar	arg2;
 	NumericVar	result;
@@ -2453,7 +2492,7 @@ numeric_sub(PG_FUNCTION_ARGS)
 	 * Handle NaN
 	 */
 	if (NUMERIC_IS_NAN(num1) || NUMERIC_IS_NAN(num2))
-		PG_RETURN_NUMERIC(make_result(&const_nan));
+		return make_result(&const_nan);
 
 	/*
 	 * Unpack the values, let sub_var() compute the result and return it.
@@ -2464,11 +2503,11 @@ numeric_sub(PG_FUNCTION_ARGS)
 	init_var(&result);
 	sub_var(&arg1, &arg2, &result);
 
-	res = make_result(&result);
+	res = make_result_opt_error(&result, have_error);
 
 	free_var(&result);
 
-	PG_RETURN_NUMERIC(res);
+	return res;
 }
 
 
@@ -2482,6 +2521,24 @@ numeric_mul(PG_FUNCTION_ARGS)
 {
 	Numeric		num1 = PG_GETARG_NUMERIC(0);
 	Numeric		num2 = PG_GETARG_NUMERIC(1);
+	Numeric		res;
+
+	res = numeric_mul_opt_error(num1, num2, NULL);
+
+	PG_RETURN_NUMERIC(res);
+}
+
+
+/*
+ * numeric_mul_opt_error() -
+ *
+ *	Internal version of numeric_mul().  If "*have_error" flag is provided,
+ *	on error it's set to true, NULL returned.  This is helpful when caller
+ *	need to handle errors by itself.
+ */
+Numeric
+numeric_mul_opt_error(Numeric num1, Numeric num2, bool *have_error)
+{
 	NumericVar	arg1;
 	NumericVar	arg2;
 	NumericVar	result;
@@ -2491,7 +2548,7 @@ numeric_mul(PG_FUNCTION_ARGS)
 	 * Handle NaN
 	 */
 	if (NUMERIC_IS_NAN(num1) || NUMERIC_IS_NAN(num2))
-		PG_RETURN_NUMERIC(make_result(&const_nan));
+		return make_result(&const_nan);
 
 	/*
 	 * Unpack the values, let mul_var() compute the result and return it.
@@ -2506,11 +2563,11 @@ numeric_mul(PG_FUNCTION_ARGS)
 	init_var(&result);
 	mul_var(&arg1, &arg2, &result, arg1.dscale + arg2.dscale);
 
-	res = make_result(&result);
+	res = make_result_opt_error(&result, have_error);
 
 	free_var(&result);
 
-	PG_RETURN_NUMERIC(res);
+	return res;
 }
 
 
@@ -2524,6 +2581,24 @@ numeric_div(PG_FUNCTION_ARGS)
 {
 	Numeric		num1 = PG_GETARG_NUMERIC(0);
 	Numeric		num2 = PG_GETARG_NUMERIC(1);
+	Numeric		res;
+
+	res = numeric_div_opt_error(num1, num2, NULL);
+
+	PG_RETURN_NUMERIC(res);
+}
+
+
+/*
+ * numeric_div_opt_error() -
+ *
+ *	Internal version of numeric_div().  If "*have_error" flag is provided,
+ *	on error it's set to true, NULL returned.  This is helpful when caller
+ *	need to handle errors by itself.
+ */
+Numeric
+numeric_div_opt_error(Numeric num1, Numeric num2, bool *have_error)
+{
 	NumericVar	arg1;
 	NumericVar	arg2;
 	NumericVar	result;
@@ -2534,7 +2609,7 @@ numeric_div(PG_FUNCTION_ARGS)
 	 * Handle NaN
 	 */
 	if (NUMERIC_IS_NAN(num1) || NUMERIC_IS_NAN(num2))
-		PG_RETURN_NUMERIC(make_result(&const_nan));
+		return make_result(&const_nan);
 
 	/*
 	 * Unpack the arguments
@@ -2550,15 +2625,24 @@ numeric_div(PG_FUNCTION_ARGS)
 	rscale = select_div_scale(&arg1, &arg2);
 
 	/*
+	 * If "have_error" is provided, check for division by zero here
+	 */
+	if (have_error && (arg2.ndigits == 0 || arg2.digits[0] == 0))
+	{
+		*have_error = true;
+		return NULL;
+	}
+
+	/*
 	 * Do the divide and return the result
 	 */
 	div_var(&arg1, &arg2, &result, rscale, true);
 
-	res = make_result(&result);
+	res = make_result_opt_error(&result, have_error);
 
 	free_var(&result);
 
-	PG_RETURN_NUMERIC(res);
+	return res;
 }
 
 
@@ -2615,25 +2699,52 @@ numeric_mod(PG_FUNCTION_ARGS)
 	Numeric		num1 = PG_GETARG_NUMERIC(0);
 	Numeric		num2 = PG_GETARG_NUMERIC(1);
 	Numeric		res;
+
+	res = numeric_mod_opt_error(num1, num2, NULL);
+
+	PG_RETURN_NUMERIC(res);
+}
+
+
+/*
+ * numeric_mod_opt_error() -
+ *
+ *	Internal version of numeric_mod().  If "*have_error" flag is provided,
+ *	on error it's set to true, NULL returned.  This is helpful when caller
+ *	need to handle errors by itself.
+ */
+Numeric
+numeric_mod_opt_error(Numeric num1, Numeric num2, bool *have_error)
+{
+	Numeric		res;
 	NumericVar	arg1;
 	NumericVar	arg2;
 	NumericVar	result;
 
 	if (NUMERIC_IS_NAN(num1) || NUMERIC_IS_NAN(num2))
-		PG_RETURN_NUMERIC(make_result(&const_nan));
+		return make_result(&const_nan);
 
 	init_var_from_num(num1, &arg1);
 	init_var_from_num(num2, &arg2);
 
 	init_var(&result);
 
+	/*
+	 * If "have_error" is provided, check for division by zero here
+	 */
+	if (have_error && (arg2.ndigits == 0 || arg2.digits[0] == 0))
+	{
+		*have_error = true;
+		return NULL;
+	}
+
 	mod_var(&arg1, &arg2, &result);
 
-	res = make_result(&result);
+	res = make_result_opt_error(&result, NULL);
 
 	free_var(&result);
 
-	PG_RETURN_NUMERIC(res);
+	return res;
 }
 
 
@@ -3090,52 +3201,75 @@ int4_numeric(PG_FUNCTION_ARGS)
 	PG_RETURN_NUMERIC(res);
 }
 
-
-Datum
-numeric_int4(PG_FUNCTION_ARGS)
+int32
+numeric_int4_opt_error(Numeric num, bool *have_error)
 {
-	Numeric		num = PG_GETARG_NUMERIC(0);
 	NumericVar	x;
 	int32		result;
 
 	/* XXX would it be better to return NULL? */
 	if (NUMERIC_IS_NAN(num))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("cannot convert NaN to integer")));
+	{
+		if (have_error)
+		{
+			*have_error = true;
+			return 0;
+		}
+		else
+		{
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("cannot convert NaN to integer")));
+		}
+	}
 
 	/* Convert to variable format, then convert to int4 */
 	init_var_from_num(num, &x);
-	result = numericvar_to_int32(&x);
-	PG_RETURN_INT32(result);
+
+	if (!numericvar_to_int32(&x, &result))
+	{
+		if (have_error)
+		{
+			*have_error = true;
+			return 0;
+		}
+		else
+		{
+			ereport(ERROR,
+					(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+					 errmsg("integer out of range")));
+		}
+	}
+
+	return result;
+}
+
+Datum
+numeric_int4(PG_FUNCTION_ARGS)
+{
+	Numeric		num = PG_GETARG_NUMERIC(0);
+
+	PG_RETURN_INT32(numeric_int4_opt_error(num, NULL));
 }
 
 /*
  * Given a NumericVar, convert it to an int32. If the NumericVar
- * exceeds the range of an int32, raise the appropriate error via
- * ereport(). The input NumericVar is *not* free'd.
+ * exceeds the range of an int32, false is returned, otherwise true is returned.
+ * The input NumericVar is *not* free'd.
  */
-static int32
-numericvar_to_int32(const NumericVar *var)
+static bool
+numericvar_to_int32(const NumericVar *var, int32 *result)
 {
-	int32		result;
 	int64		val;
 
 	if (!numericvar_to_int64(var, &val))
-		ereport(ERROR,
-				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
-				 errmsg("integer out of range")));
+		return false;
 
 	/* Down-convert to int4 */
-	result = (int32) val;
+	*result = (int32) val;
 
 	/* Test for overflow by reverse-conversion. */
-	if ((int64) result != val)
-		ereport(ERROR,
-				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
-				 errmsg("integer out of range")));
-
-	return result;
+	return ((int64) *result == val);
 }
 
 Datum
@@ -6098,13 +6232,15 @@ get_str_from_var_sci(const NumericVar *var, int rscale)
 
 
 /*
- * make_result() -
+ * make_result_opt_error() -
  *
  *	Create the packed db numeric format in palloc()'d memory from
- *	a variable.
+ *	a variable.  If "*have_error" flag is provided, on error it's set to
+ *	true, NULL returned.  This is helpful when caller need to handle errors
+ *	by itself.
  */
 static Numeric
-make_result(const NumericVar *var)
+make_result_opt_error(const NumericVar *var, bool *have_error)
 {
 	Numeric		result;
 	NumericDigit *digits = var->digits;
@@ -6175,9 +6311,19 @@ make_result(const NumericVar *var)
 	/* Check for overflow of int16 fields */
 	if (NUMERIC_WEIGHT(result) != weight ||
 		NUMERIC_DSCALE(result) != var->dscale)
-		ereport(ERROR,
-				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
-				 errmsg("value overflows numeric format")));
+	{
+		if (have_error)
+		{
+			*have_error = true;
+			return NULL;
+		}
+		else
+		{
+			ereport(ERROR,
+					(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+					 errmsg("value overflows numeric format")));
+		}
+	}
 
 	dump_numeric("make_result()", result);
 	return result;
@@ -6185,6 +6331,18 @@ make_result(const NumericVar *var)
 
 
 /*
+ * make_result() -
+ *
+ *	An interface to make_result_opt_error() without "have_error" argument.
+ */
+static Numeric
+make_result(const NumericVar *var)
+{
+	return make_result_opt_error(var, NULL);
+}
+
+
+/*
  * apply_typmod() -
  *
  *	Do bounds checking and rounding according to the attributes