Fix CONVERT function behavior for BINARY and VARBINARY types (#3007)

This change addresses inconsistencies in the CONVERT function's behavior when used with BINARY and VARBINARY types in Babelfish. Previously, Babelfish was not correctly handling style arguments and hexadecimal input for these conversions. With this change, the behavior now more closely aligns with SQL Server's implementation. For CONVERT(BINARY(n), '0x...', 1), the function now correctly interprets the input string as hexadecimal values instead of ASCII characters, adhering to the specified style. When NULL is provided as the style argument, the function now correctly returns NULL for both BINARY and VARBINARY types. For both BINARY and VARBINARY conversions, the function now properly considers the style argument, ensuring consistent behavior across different styles. Fixed an issue where style 2 was not being handled correctly, leading to unexpected results. Issues Resolved Task: BABEL-2736 Signed-off-by: Rahul Parande <[email protected]>
babelfish-for-postgresql · Oct 22, 2024 · 4bae220 · 4bae220
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diff --git a/contrib/babelfishpg_tsql/sql/sys_function_helpers.sql b/contrib/babelfishpg_tsql/sql/sys_function_helpers.sql
@@ -9655,6 +9655,112 @@ $BODY$
 LANGUAGE plpgsql
 STABLE;
 
+CREATE OR REPLACE FUNCTION sys.babelfish_conv_helper_to_varbinary(IN arg anyelement,
+                                                                  IN try BOOL,
+                                                                  IN p_style NUMERIC DEFAULT 0)
+RETURNS sys.varbinary
+AS
+$BODY$
+BEGIN
+    IF try THEN
+        RETURN sys.babelfish_try_conv_to_varbinary(arg, p_style);
+    ELSE
+        IF pg_typeof(arg) IN ('text'::regtype, 'sys.ntext'::regtype, 'sys.nvarchar'::regtype, 'sys.bpchar'::regtype, 'sys.nchar'::regtype) THEN
+            RETURN sys.babelfish_conv_string_to_varbinary(arg, p_style);
+        ELSE
+            RETURN CAST(arg AS sys.varbinary);
+        END IF;
+    END IF;
+END;
+$BODY$
+LANGUAGE plpgsql
+IMMUTABLE;  
+
+CREATE OR REPLACE FUNCTION sys.babelfish_conv_helper_to_varbinary(IN arg sys.VARCHAR,
+                                                                  IN try BOOL,
+                                                                  IN p_style NUMERIC DEFAULT 0)
+RETURNS sys.varbinary
+AS
+$BODY$
+BEGIN
+    IF try THEN
+        RETURN sys.babelfish_try_conv_string_to_varbinary(arg, p_style);
+    ELSE
+        RETURN sys.babelfish_conv_string_to_varbinary(arg, p_style);
+    END IF;
+END;
+$BODY$
+LANGUAGE plpgsql
+IMMUTABLE; 
+
+CREATE OR REPLACE FUNCTION sys.babelfish_try_conv_string_to_varbinary(IN arg sys.VARCHAR,                                                       
+                                                                      IN p_style NUMERIC DEFAULT 0)
+RETURNS sys.varbinary
+AS
+$BODY$
+BEGIN
+    RETURN sys.babelfish_conv_string_to_varbinary(arg, p_style);
+    EXCEPTION
+        WHEN OTHERS THEN
+            RETURN NULL;
+END;
+$BODY$
+LANGUAGE plpgsql
+IMMUTABLE;
+
+CREATE OR REPLACE FUNCTION sys.babelfish_try_conv_to_varbinary(IN arg anyelement,
+                                                               IN p_style NUMERIC DEFAULT 0)
+RETURNS sys.varbinary
+AS
+$BODY$
+BEGIN
+    IF pg_typeof(arg) IN ('text'::regtype, 'sys.ntext'::regtype, 'sys.nvarchar'::regtype, 'sys.bpchar'::regtype, 'sys.nchar'::regtype) THEN
+        RETURN sys.babelfish_conv_string_to_varbinary(arg, p_style);
+    ELSE
+        RETURN CAST(arg AS sys.varbinary);
+    END IF;
+    EXCEPTION
+        WHEN OTHERS THEN
+            RETURN NULL;
+END;
+$BODY$
+LANGUAGE plpgsql
+IMMUTABLE;  
+
+-- Helper function to convert to binary or varbinary
+CREATE OR REPLACE FUNCTION sys.babelfish_conv_string_to_varbinary(IN input_value sys.VARCHAR, IN style NUMERIC DEFAULT 0) 
+RETURNS sys.varbinary 
+AS 
+$BODY$
+DECLARE
+    result bytea; 
+BEGIN
+    IF style = 0 THEN
+        RETURN CAST(input_value AS sys.varbinary);
+    ELSIF style = 1 THEN
+        -- Handle hexadecimal conversion
+        IF (PG_CATALOG.left(input_value, 2) = '0x' COLLATE "C" AND PG_CATALOG.length(input_value) % 2 = 0) THEN
+            result := decode(substring(input_value from 3), 'hex');
+        ELSE
+            RAISE EXCEPTION 'Error converting data type varchar to varbinary.';
+        END IF;
+    ELSIF style = 2 THEN
+        IF PG_CATALOG.left(input_value, 2) = '0x' COLLATE "C" THEN
+            RAISE EXCEPTION 'Error converting data type varchar to varbinary.';
+        ELSE
+            result := decode(input_value, 'hex');
+        END IF;
+    ELSE
+        RAISE EXCEPTION 'The style % is not supported for conversions from varchar to varbinary.', style;
+    END IF;
+
+    RETURN CAST(result AS sys.varbinary);
+END;
+$BODY$ 
+LANGUAGE plpgsql
+IMMUTABLE
+STRICT;
+
 -- convertion to varchar
 CREATE OR REPLACE FUNCTION sys.babelfish_conv_helper_to_varchar(IN typename TEXT,
                                                         IN arg TEXT,

diff --git a/contrib/babelfishpg_tsql/sql/upgrades/babelfishpg_tsql--4.3.0--4.4.0.sql b/contrib/babelfishpg_tsql/sql/upgrades/babelfishpg_tsql--4.3.0--4.4.0.sql
@@ -10555,6 +10555,112 @@ BEGIN
 END;
 $$ LANGUAGE plpgsql STABLE PARALLEL SAFE;
 
+CREATE OR REPLACE FUNCTION sys.babelfish_conv_helper_to_varbinary(IN arg anyelement,
+                                                                  IN try BOOL,
+                                                                  IN p_style NUMERIC DEFAULT 0)
+RETURNS sys.varbinary
+AS
+$BODY$
+BEGIN
+    IF try THEN
+        RETURN sys.babelfish_try_conv_to_varbinary(arg, p_style);
+    ELSE
+        IF pg_typeof(arg) IN ('text'::regtype, 'sys.ntext'::regtype, 'sys.nvarchar'::regtype, 'sys.bpchar'::regtype, 'sys.nchar'::regtype) THEN
+            RETURN sys.babelfish_conv_string_to_varbinary(arg, p_style);
+        ELSE
+            RETURN CAST(arg AS sys.varbinary);
+        END IF;
+    END IF;
+END;
+$BODY$
+LANGUAGE plpgsql
+IMMUTABLE;  
+
+CREATE OR REPLACE FUNCTION sys.babelfish_conv_helper_to_varbinary(IN arg sys.VARCHAR,
+                                                                  IN try BOOL,
+                                                                  IN p_style NUMERIC DEFAULT 0)
+RETURNS sys.varbinary
+AS
+$BODY$
+BEGIN
+    IF try THEN
+        RETURN sys.babelfish_try_conv_string_to_varbinary(arg, p_style);
+    ELSE
+        RETURN sys.babelfish_conv_string_to_varbinary(arg, p_style);
+    END IF;
+END;
+$BODY$
+LANGUAGE plpgsql
+IMMUTABLE; 
+
+CREATE OR REPLACE FUNCTION sys.babelfish_try_conv_string_to_varbinary(IN arg sys.VARCHAR,                                                       
+                                                                      IN p_style NUMERIC DEFAULT 0)
+RETURNS sys.varbinary
+AS
+$BODY$
+BEGIN
+    RETURN sys.babelfish_conv_string_to_varbinary(arg, p_style);
+    EXCEPTION
+        WHEN OTHERS THEN
+            RETURN NULL;
+END;
+$BODY$
+LANGUAGE plpgsql
+IMMUTABLE;
+
+CREATE OR REPLACE FUNCTION sys.babelfish_try_conv_to_varbinary(IN arg anyelement,
+                                                               IN p_style NUMERIC DEFAULT 0)
+RETURNS sys.varbinary
+AS
+$BODY$
+BEGIN
+    IF pg_typeof(arg) IN ('text'::regtype, 'sys.ntext'::regtype, 'sys.nvarchar'::regtype, 'sys.bpchar'::regtype, 'sys.nchar'::regtype) THEN
+        RETURN sys.babelfish_conv_string_to_varbinary(arg, p_style);
+    ELSE
+        RETURN CAST(arg AS sys.varbinary);
+    END IF;
+    EXCEPTION
+        WHEN OTHERS THEN
+            RETURN NULL;
+END;
+$BODY$
+LANGUAGE plpgsql
+IMMUTABLE;  
+
+-- Helper function to convert to binary or varbinary
+CREATE OR REPLACE FUNCTION sys.babelfish_conv_string_to_varbinary(IN input_value sys.VARCHAR, IN style NUMERIC DEFAULT 0) 
+RETURNS sys.varbinary 
+AS 
+$BODY$
+DECLARE
+    result bytea; 
+BEGIN
+    IF style = 0 THEN
+        RETURN CAST(input_value AS sys.varbinary);
+    ELSIF style = 1 THEN
+        -- Handle hexadecimal conversion
+        IF (PG_CATALOG.left(input_value, 2) = '0x' COLLATE "C" AND PG_CATALOG.length(input_value) % 2 = 0) THEN
+            result := decode(substring(input_value from 3), 'hex');
+        ELSE
+            RAISE EXCEPTION 'Error converting data type varchar to varbinary.';
+        END IF;
+    ELSIF style = 2 THEN
+        IF PG_CATALOG.left(input_value, 2) = '0x' COLLATE "C" THEN
+            RAISE EXCEPTION 'Error converting data type varchar to varbinary.';
+        ELSE
+            result := decode(input_value, 'hex');
+        END IF;
+    ELSE
+        RAISE EXCEPTION 'The style % is not supported for conversions from varchar to varbinary.', style;
+    END IF;
+
+    RETURN CAST(result AS sys.varbinary);
+END;
+$BODY$ 
+LANGUAGE plpgsql
+IMMUTABLE
+STRICT;
+
 CREATE OR REPLACE FUNCTION sys.replace (input_string sys.VARCHAR, pattern sys.VARCHAR, replacement sys.VARCHAR)
 RETURNS sys.VARCHAR AS
 $BODY$

diff --git a/contrib/babelfishpg_tsql/src/backend_parser/gram-tsql-epilogue.y.c b/contrib/babelfishpg_tsql/src/backend_parser/gram-tsql-epilogue.y.c
@@ -216,6 +216,16 @@ TsqlFunctionConvert(TypeName *typename, Node *arg, Node *style, bool try, int lo
 		 */
 		result = makeTypeCast(helperFuncCall, typename, location);
 	}
+
+	else if (strcmp(typename_string, "binary") == 0 || strcmp(typename_string, "varbinary") == 0)
+	{
+			Node	   *helperFuncCall;
+			helperFuncCall = (Node *) makeFuncCall(TsqlSystemFuncName("babelfish_conv_helper_to_varbinary"), args, COERCE_EXPLICIT_CALL, location);
+
+			// add a type cast on top of the CONVERT helper function so typmod can be applied
+			result = makeTypeCast(helperFuncCall, typename, location);
+	}
+
 	else
 	{
 		if (try)