MDEV-17563 Different results using table or view when comparing values of time type

MDEV-17625 Different warnings when comparing a garbage to DATETIME vs TIME

- Splitting processes of data type conversion (to TIME/DATE,DATETIME)
  and warning generation.
  Warning are now only get collected during conversion (in an "int" variable),
  and are pushed in the very end of conversion (not in parallel).
  Warnings generated by the low level routines str_to_xxx() and number_to_xxx()
  can now be changed at the end, when TIME_FUZZY_DATES is applied,
  from "Invalid value" to "Truncated invalid value".

  Now "Illegal value" is issued only when the low level routine returned
  an error and TIME_FUZZY_DATES was not set. Otherwise, if the low level
  routine returned "false" (success), or if NULL was converted to a zero
  datetime by TIME_FUZZY_DATES, then "Truncated illegal value"
  is issued. This gives better warnings.

- Methods Type_handler::Item_get_date() and
  Type_handler::Item_func_hybrid_field_type_get_date() now only
  convert and collect warning information, but do not push warnings.

- Changing the return data type for Type_handler::Item_get_date()
  and Type_handler::Item_func_hybrid_field_type_get_date() from
  "bool" to "void". The conversion result (success vs error) can be
  checked by testing ltime->time_type. MYSQL_TIME_{NONE|ERROR}
  mean mean error, other values mean success.

- Adding new wrapper methods Type_handler::Item_get_date_with_warn() and
  Type_handler::Item_func_hybrid_field_type_get_date_with_warn()
  to do conversion followed by raising warnings, and changing
  the code to call new Type_handler::***_with_warn() methods.

- Adding a helper class Temporal::Status, a wrapper
  for MYSQL_TIME_STATUS with automatic initialization.

- Adding a helper class Temporal::Warn, to collect warnings
  but without actually raising them. Moving a part of ErrConv
  into a separate class ErrBuff, and deriving both Temporal::Warn
  and ErrConv from ErrBuff. The ErrBuff part of Temporal::Warn
  is used to collect textual representation of the input data.

- Adding a helper class Temporal::Warn_push. It's used
  to collect warning information during conversion, and
  automatically pushes warnings to the diagnostics area
  on its destructor time (in case of non-zero warning).

- Moving more code from various functions inside class Temporal.

- Adding more Temporal_hybrid constructors and
  protected Temporal methods make_from_xxx(),
  which convert and only collect warning information, but do not
  actually raise warnings.

- Now the low level functions  str_to_datetime() and str_to_time()
  always set status->warning if the return value is "true" (error).

- Now the low level functions number_to_time() and number_to_datetime()
  set the "*was_cut" argument if the return value is "true" (error).

- Adding a few DBUG_ASSERTs to make sure that str_to_xxx() and
  number_to_xxx() always set warnings on error.

- Adding new warning flags MYSQL_TIME_WARN_EDOM and MYSQL_TIME_WARN_ZERO_DATE
  for the code symmetry. Before this change there was a special
  code path for (rc==true && was_cut==0) which was treated by
  Field_temporal::store_invalid_with_warning as "zero date violation".
  Now was_cut==0 always means that there are no any error/warnings/notes
  to be raised, not matter what rc is.

- Using new Temporal_hybrid constructors in combination with
  Temporal::Warn_push inside str_to_datetime_with_warn(),
  double_to_datetime_with_warn(), int_to_datetime_with_warn(),
  Field::get_date(), Item::get_date_from_string(), and a few other places.

- Removing methods Dec_ptr::to_datetime_with_warn(),
  Year::to_time_with_warn(), my_decimal::to_datetime_with_warn(),
  Dec_ptr::to_datetime_with_warn().
  Fixing Sec6::to_time() and Sec6::to_datetime() to
  convert and only collect warnings, without raising warnings.
  Now warning raising functionality resides in Temporal::Warn_push.

- Adding classes Longlong_hybrid_null and Double_null, to
  return both value and the "IS NULL" flag. Adding methods
  Item::to_double_null(), to_longlong_hybrid_null(),
  Item_func_hybrid_field_type::to_longlong_hybrid_null_op(),
  Item_func_hybrid_field_type::to_double_null_op().
  Removing separate classes VInt and VInt_op, as they
  have been replaced by a single class Longlong_hybrid_null.

- Adding a helper method Temporal::type_name_by_timestamp_type(),
  moving a part of make_truncated_value_warning() into it,
  and reusing in Temporal::Warn::push_conversion_warnings().

- Removing Item::make_zero_date() and
  Item_func_hybrid_field_type::make_zero_mysql_time().
  They provided duplicate functionality.
  Now this code resides in Temporal::make_fuzzy_date().
  The latter is now called for all Item types when data type
  conversion (to DATE/TIME/DATETIME) is involved, including
  Item_field and Item_direct_view_ref.
  This fixes MDEV-17563: Item_direct_view_ref now correctly converts
  NULL to a zero date when TIME_FUZZY_DATES says so.

1 files changed, 21 insertions, 16 deletions

diff --git a/sql/item_func.h b/sql/item_func.h
index 602b13fad7a..660d39f48ea 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -680,11 +680,6 @@ class Item_func_hybrid_field_type: public Item_hybrid_func
     DBUG_ASSERT((res != NULL) ^ null_value);
     return res;
   }
-  bool make_zero_mysql_time(MYSQL_TIME *ltime, date_mode_t fuzzydate)
-  {
-    bzero(ltime, sizeof(*ltime));
-    return null_value|= !(fuzzydate & TIME_FUZZY_DATES);
-  }
 
 public:
   // Value methods that involve no conversion
@@ -723,10 +718,6 @@ public:
   double val_real_from_time_op();
   double val_real_from_int_op();
 
-  bool get_date_from_str_op(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate);
-  bool get_date_from_real_op(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate);
-  bool get_date_from_int_op(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate);
-
 public:
   Item_func_hybrid_field_type(THD *thd):
     Item_hybrid_func(thd)
@@ -770,11 +761,11 @@ public:
     DBUG_ASSERT(null_value == (res == NULL));
     return res;
   }
-  bool get_date(THD *thd, MYSQL_TIME *res, date_mode_t fuzzydate)
+  bool get_date(THD *thd, MYSQL_TIME *to, date_mode_t mode)
   {
     DBUG_ASSERT(fixed);
     return Item_func_hybrid_field_type::type_handler()->
-           Item_func_hybrid_field_type_get_date(thd, this, res, fuzzydate);
+           Item_func_hybrid_field_type_get_date_with_warn(thd, this, to, mode);
   }
 
   /**
@@ -794,6 +785,10 @@ public:
     */
     return Longlong_null(nr, null_value);
   }
+  Longlong_hybrid_null to_longlong_hybrid_null_op()
+  {
+    return Longlong_hybrid_null(to_longlong_null_op(), unsigned_flag);
+  }
 
   /**
      @brief Performs the operation that this functions implements when the
@@ -802,6 +797,12 @@ public:
      @return The result of the operation.
   */
   virtual double real_op()= 0;
+  Double_null to_double_null_op()
+  {
+    // val_real() must be caleed on a separate line. See to_longlong_null()
+    double nr= real_op();
+    return Double_null(nr, null_value);
+  }
 
   /**
      @brief Performs the operation that this functions implements when the
@@ -1180,8 +1181,10 @@ public:
   double val_real() { return VDec(this).to_double(); }
   longlong val_int() { return VDec(this).to_longlong(unsigned_flag); }
   my_decimal *val_decimal(my_decimal*);
-  bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate)
-  { return VDec(this).to_datetime_with_warn(thd, ltime, fuzzydate, this); }
+  bool get_date(THD *thd, MYSQL_TIME *to, date_mode_t mode)
+  {
+    return decimal_to_datetime_with_warn(thd, VDec(this).ptr(), to, mode, NULL);
+  }
   const Type_handler *type_handler() const { return &type_handler_newdecimal; }
   void fix_length_and_dec_generic() {}
   bool fix_length_and_dec()
@@ -2292,7 +2295,7 @@ public:
   }
   bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate)
   {
-    return type_handler()->Item_get_date(thd, this, ltime, fuzzydate);
+    return type_handler()->Item_get_date_with_warn(thd, this, ltime, fuzzydate);
   }
 };
 
@@ -2602,7 +2605,9 @@ public:
   { return create_table_field_from_handler(table); }
   bool check_vcol_func_processor(void *arg);
   bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate)
-  { return type_handler()->Item_get_date(thd, this, ltime, fuzzydate); }
+  {
+    return type_handler()->Item_get_date_with_warn(thd, this, ltime, fuzzydate);
+  }
 };
 
 
@@ -2832,7 +2837,7 @@ public:
   { return val_decimal_from_real(dec_buf); }
   bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate)
   {
-    return type_handler()->Item_get_date(thd, this, ltime, fuzzydate);
+    return type_handler()->Item_get_date_with_warn(thd, this, ltime, fuzzydate);
   }
   /* TODO: fix to support views */
   const char *func_name() const { return "get_system_var"; }