MDEV-36390: Minor refactoring of the method get_expr_query at the classes sp_instr_cpush/sp_instr_cursor_copy_struct

Duplicated code from methods
  sp_instr_cpush::get_expr_query
  sp_instr_cursor_copy_struct::get_expr_query
were extracted to the standalone function get_cursor_query

Additionally, added correct parsing of a cursor definition with
a new line or TAB instead of the space immediately after FOR/IS.

mysql-test/main/sp_validation.result

@@ -1993,4 +1993,96 @@ f1()
 # Clean up
 DROP FUNCTION f1;
 DROP TABLE t1;
+#
+# MDEV-36390: Minor refactoring of the method get_expr_query at the classes sp_instr_cpush/sp_instr_cursor_copy_struct
+#
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1);
+CREATE OR REPLACE PROCEDURE p1()
+BEGIN
+DECLARE va INT;
+# Check that the TAB character after the clause FOR is skipped and
+# the body of cursor is remembered correctly for subsequent re-parsing
+DECLARE cur CURSOR FOR	SELECT a FROM t1;
+OPEN cur;
+FETCH cur INTO va;
+SELECT va;
+CLOSE cur;
+END;
+$
+CREATE OR REPLACE PROCEDURE p2()
+BEGIN
+DECLARE va INT;
+# Check that the newline character after the clause FOR is skipped and
+# the body of cursor is remembered correctly for subsequent re-parsing
+DECLARE cur CURSOR FOR
+SELECT a FROM t1;
+OPEN cur;
+FETCH cur INTO va;
+SELECT va;
+CLOSE cur;
+END;
+$
+CREATE OR REPLACE PROCEDURE p3()
+BEGIN
+DECLARE va INT;
+# Check that C-style comment and the newline character after
+# the clause FOR is skipped and the body of cursor is remembered
+# correctly for subsequent re-parsing
+DECLARE cur CURSOR FOR /* Explicit comment */
+SELECT a FROM t1;
+OPEN cur;
+FETCH cur INTO va;
+SELECT va;
+CLOSE cur;
+END;
+$
+CREATE OR REPLACE PROCEDURE p4()
+BEGIN
+DECLARE va INT;
+# Check that SQL-style comment and the newline character after
+# the clause FOR is skipped and the body of cursor is remembered
+# correctly for subsequent re-parsing
+DECLARE cur CURSOR FOR -- Explicit comment
+SELECT a FROM t1;
+OPEN cur;
+FETCH cur INTO va;
+SELECT va;
+CLOSE cur;
+END;
+$
+CALL p1();
+va
+1
+CALL p2();
+va
+1
+CALL p3();
+va
+1
+CALL p4();
+va
+1
+ALTER TABLE t1 COMMENT 'The Comment 1';
+# The following statements will run re-parsing of
+# cursor declaration statements inside the stored
+# procedures p1, p2, p3, p4.
+CALL p1();
+va
+1
+CALL p2();
+va
+1
+CALL p3();
+va
+1
+CALL p4();
+va
+1
+# Clean up
+DROP PROCEDURE p1;
+DROP PROCEDURE p2;
+DROP PROCEDURE p3;
+DROP PROCEDURE p4;
+DROP TABLE t1;
 SET sql_mode = default;

mysql-test/main/sp_validation.test

@@ -2795,5 +2795,96 @@ SELECT f1();
 DROP FUNCTION f1;
 DROP TABLE t1;
 
+--echo #
+--echo # MDEV-36390: Minor refactoring of the method get_expr_query at the classes sp_instr_cpush/sp_instr_cursor_copy_struct
+--echo #
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1);
+
+--delimiter $
+
+CREATE OR REPLACE PROCEDURE p1()
+BEGIN
+  DECLARE va INT;
+  # Check that the TAB character after the clause FOR is skipped and
+  # the body of cursor is remembered correctly for subsequent re-parsing
+  DECLARE cur CURSOR FOR	SELECT a FROM t1;
+
+  OPEN cur;
+  FETCH cur INTO va;
+  SELECT va;
+  CLOSE cur;
+END;
+$
+
+CREATE OR REPLACE PROCEDURE p2()
+BEGIN
+  DECLARE va INT;
+  # Check that the newline character after the clause FOR is skipped and
+  # the body of cursor is remembered correctly for subsequent re-parsing
+  DECLARE cur CURSOR FOR
+  SELECT a FROM t1;
+
+  OPEN cur;
+  FETCH cur INTO va;
+  SELECT va;
+  CLOSE cur;
+END;
+$
+
+CREATE OR REPLACE PROCEDURE p3()
+BEGIN
+  DECLARE va INT;
+  # Check that C-style comment and the newline character after
+  # the clause FOR is skipped and the body of cursor is remembered
+  # correctly for subsequent re-parsing
+  DECLARE cur CURSOR FOR /* Explicit comment */
+  SELECT a FROM t1;
+
+  OPEN cur;
+  FETCH cur INTO va;
+  SELECT va;
+  CLOSE cur;
+END;
+$
+
+CREATE OR REPLACE PROCEDURE p4()
+BEGIN
+  DECLARE va INT;
+  # Check that SQL-style comment and the newline character after
+  # the clause FOR is skipped and the body of cursor is remembered
+  # correctly for subsequent re-parsing
+  DECLARE cur CURSOR FOR -- Explicit comment
+  SELECT a FROM t1;
+
+  OPEN cur;
+  FETCH cur INTO va;
+  SELECT va;
+  CLOSE cur;
+END;
+$
+
+--delimiter ;
+
+CALL p1();
+CALL p2();
+CALL p3();
+CALL p4();
+ALTER TABLE t1 COMMENT 'The Comment 1';
+--echo # The following statements will run re-parsing of
+--echo # cursor declaration statements inside the stored
+--echo # procedures p1, p2, p3, p4.
+CALL p1();
+CALL p2();
+CALL p3();
+CALL p4();
+
+--echo # Clean up
+DROP PROCEDURE p1;
+DROP PROCEDURE p2;
+DROP PROCEDURE p3;
+DROP PROCEDURE p4;
+DROP TABLE t1;
+
 SET sql_mode = default;
 --enable_ps2_protocol

sql/sp_instr.h

@@ -1227,6 +1227,32 @@ public:
 }; // class sp_instr_hreturn : public sp_instr_jump
 
 
+/**
+  Get a query text associated with the cursor.
+*/
+
+static inline LEX_CSTRING get_cursor_query(const LEX_CSTRING &cursor_stmt)
+{
+  /*
+    Lexer on processing the clause CURSOR FOR / CURSOR IS doesn't
+    move a pointer on cpp_buf after the token FOR/IS so skip it explicitly
+    in order to get correct value of cursor's query string.
+  */
+
+  if (strncasecmp(cursor_stmt.str, "FOR", 3) == 0 &&
+      my_isspace(current_thd->variables.character_set_client,
+                 cursor_stmt.str[3]))
+    return LEX_CSTRING{cursor_stmt.str + 4, cursor_stmt.length - 4};
+
+  if (strncasecmp(cursor_stmt.str, "IS", 2) == 0 &&
+      my_isspace(current_thd->variables.character_set_client,
+                 cursor_stmt.str[2]))
+    return LEX_CSTRING{cursor_stmt.str + 3, cursor_stmt.length - 3};
+
+  return cursor_stmt;
+}
+
+
 /**
   This is DECLARE CURSOR
 */
@@ -1287,16 +1313,7 @@ public:
 protected:
   LEX_CSTRING get_expr_query() const override
   {
-    /*
+    return get_cursor_query(m_cursor_stmt);
-      Lexer on processing the clause CURSOR FOR / CURSOR IS doesn't
-      move a pointer on cpp_buf after the token FOR/IS so skip it explicitly
-      in order to get correct value of cursor's query string.
-    */
-    if (strncasecmp(m_cursor_stmt.str, "FOR ", 4) == 0)
-      return LEX_CSTRING{m_cursor_stmt.str + 4, m_cursor_stmt.length - 4};
-    if (strncasecmp(m_cursor_stmt.str, "IS ", 3) == 0)
-      return LEX_CSTRING{m_cursor_stmt.str + 3, m_cursor_stmt.length - 3};
-    return m_cursor_stmt;
   }
 
   bool on_after_expr_parsing(THD *) override
@@ -1428,16 +1445,7 @@ public:
 protected:
   LEX_CSTRING get_expr_query() const override
   {
-    /*
+    return get_cursor_query(m_cursor_stmt);
-      Lexer on processing the clause CURSOR FOR / CURSOR IS doesn't
-      move a pointer on cpp_buf after the token FOR/IS so skip it explicitly
-      in order to get correct value of cursor's query string.
-    */
-    if (strncasecmp(m_cursor_stmt.str, "FOR ", 4) == 0)
-      return LEX_CSTRING{m_cursor_stmt.str + 4, m_cursor_stmt.length - 4};
-    if (strncasecmp(m_cursor_stmt.str, "IS ", 3) == 0)
-      return LEX_CSTRING{m_cursor_stmt.str + 3, m_cursor_stmt.length - 3};
-    return m_cursor_stmt;
   }
 
   bool on_after_expr_parsing(THD *) override