Fix for bug #26788 "mysqld (debug) aborts when inserting specific

numbers into char fields" and bug #12860 "Difference in zero padding of
exponent between Unix and Windows"

Rewrote the code that determines what 'precision' argument should be
passed to sprintf() to fit the string representation of the input number
into the field.
We get finer control over conversion by pre-calculating the exponent, so
we are able to determine which conversion format, 'e' or 'f', will be
used by sprintf().
We also remove the leading zero from the exponent on Windows to make it
compatible with the sprintf() output on other platforms.


mysql-test/r/insert.result:
  Added test cases for bug #26788 and bug #31152.
mysql-test/t/cast.test:
  Removed --replace_result, since the result is now correct on Windows.
mysql-test/t/insert.test:
  Added test cases for bug #26788 and bug #31152.
mysql-test/t/type_float.test:
  Removed --replace_result, since the result is now correct on Windows.
mysql-test/t/variables.test:
  Removed --replace_result, since the result is now correct on Windows.
sql/field.cc:
  Rewrote the code that determines what 'precision' argument should be
  passed to sprintf() to fit the string representation of the input number
  into the field.
  We get finer control over conversion by pre-calculating the exponent, so
  we are able to determine which conversion format, 'e' or 'f', will be
  used by sprintf().

6 files changed, 262 insertions, 24 deletions

diff --git a/mysql-test/r/insert.result b/mysql-test/r/insert.result
index 8a0a3ba848c..0571d31fe57 100644
--- a/mysql-test/r/insert.result
+++ b/mysql-test/r/insert.result
@@ -461,4 +461,124 @@ i
 2
 2
 DROP TABLE t1, t2;
+CREATE TABLE t1 (
+a char(20) NOT NULL,
+b char(7) DEFAULT NULL,
+c char(4) DEFAULT NULL
+);
+INSERT INTO t1(a,b,c) VALUES (9.999999e+0, 9.999999e+0, 9.999e+0);
+INSERT INTO t1(a,b,c) VALUES (1.225e-05, 1.225e-05, 1.225e-05);
+Warnings:
+Warning	1265	Data truncated for column 'c' at row 1
+INSERT INTO t1(a,b) VALUES (1.225e-04, 1.225e-04);
+INSERT INTO t1(a,b) VALUES (1.225e-01, 1.225e-01);
+INSERT INTO t1(a,b) VALUES (1.225877e-01, 1.225877e-01);
+INSERT INTO t1(a,b) VALUES (1.225e+01, 1.225e+01);
+INSERT INTO t1(a,b,c) VALUES (1.225e+01, 1.225e+01, 1.225e+01);
+INSERT INTO t1(a,b) VALUES (1.225e+05, 1.225e+05);
+INSERT INTO t1(a,b) VALUES (1.225e+10, 1.225e+10);
+INSERT INTO t1(a,b) VALUES (1.225e+15, 1.225e+15);
+INSERT INTO t1(a,b) VALUES (5000000e+0, 5000000e+0);
+INSERT INTO t1(a,b) VALUES (1.25e+78, 1.25e+78);
+INSERT INTO t1(a,b) VALUES (1.25e-94, 1.25e-94);
+INSERT INTO t1(a,b) VALUES (1.25e+203, 1.25e+203);
+INSERT INTO t1(a,b) VALUES (1.25e-175, 1.25e-175);
+INSERT INTO t1(a,c) VALUES (1.225e+0, 1.225e+0);
+INSERT INTO t1(a,c) VALUES (1.37e+0, 1.37e+0);
+INSERT INTO t1(a,c) VALUES (-1.37e+0, -1.37e+0);
+Warnings:
+Warning	1265	Data truncated for column 'c' at row 1
+INSERT INTO t1(a,c) VALUES (1.87e-3, 1.87e-3);
+Warnings:
+Warning	1265	Data truncated for column 'c' at row 1
+INSERT INTO t1(a,c) VALUES (-1.87e-2, -1.87e-2);
+Warnings:
+Warning	1265	Data truncated for column 'c' at row 1
+INSERT INTO t1(a,c) VALUES (5000e+0, 5000e+0);
+INSERT INTO t1(a,c) VALUES (-5000e+0, -5000e+0);
+Warnings:
+Warning	1265	Data truncated for column 'c' at row 1
+SELECT * FROM t1;
+a	b	c
+9.999999000000000748	10	10
+1.225e-05	1.2e-05	1e-0
+0.0001225	0.00012	NULL
+0.122499999999999998	0.1225	NULL
+0.122587699999999994	0.12259	NULL
+12.25	12.25	NULL
+12.25	12.25	12.2
+122500	122500	NULL
+12250000000	1.2e+10	NULL
+1225000000000000	1.2e+15	NULL
+5000000	5000000	NULL
+1.25e+78	1.2e+78	NULL
+1.25e-94	1.2e-94	NULL
+1.25e+203	1e+203	NULL
+1.25e-175	1e-175	NULL
+1.225000000000000089	NULL	1.23
+1.370000000000000107	NULL	1.37
+-1.37	NULL	-1.3
+0.00187	NULL	0.00
+-0.0187	NULL	-0.0
+5000	NULL	5000
+-5000	NULL	-500
+DROP TABLE t1;
+CREATE TABLE t1 (
+a char(20) NOT NULL,
+b char(7) DEFAULT NULL,
+c char(5)
+);
+INSERT INTO t1(a,b,c) VALUES (9.999999e+0, 9.999999e+0, 9.999e+0);
+INSERT INTO t1(a,b,c) VALUES (1.225e-05, 1.225e-05, 1.225e-05);
+INSERT INTO t1(a,b) VALUES (1.225e-04, 1.225e-04);
+INSERT INTO t1(a,b) VALUES (1.225e-01, 1.225e-01);
+INSERT INTO t1(a,b) VALUES (1.225877e-01, 1.225877e-01);
+INSERT INTO t1(a,b) VALUES (1.225e+01, 1.225e+01);
+INSERT INTO t1(a,b,c) VALUES (1.225e+01, 1.225e+01, 1.225e+01);
+INSERT INTO t1(a,b) VALUES (1.225e+05, 1.225e+05);
+INSERT INTO t1(a,b) VALUES (1.225e+10, 1.225e+10);
+INSERT INTO t1(a,b) VALUES (1.225e+15, 1.225e+15);
+INSERT INTO t1(a,b) VALUES (5000000e+0, 5000000e+0);
+INSERT INTO t1(a,b) VALUES (1.25e+78, 1.25e+78);
+INSERT INTO t1(a,b) VALUES (1.25e-94, 1.25e-94);
+INSERT INTO t1(a,b) VALUES (1.25e+203, 1.25e+203);
+INSERT INTO t1(a,b) VALUES (1.25e-175, 1.25e-175);
+INSERT INTO t1(a,c) VALUES (1.225e+0, 1.225e+0);
+INSERT INTO t1(a,c) VALUES (1.37e+0, 1.37e+0);
+INSERT INTO t1(a,c) VALUES (-1.37e+0, -1.37e+0);
+INSERT INTO t1(a,c) VALUES (1.87e-3, 1.87e-3);
+INSERT INTO t1(a,c) VALUES (-1.87e-2, -1.87e-2);
+Warnings:
+Warning	1265	Data truncated for column 'c' at row 1
+INSERT INTO t1(a,c) VALUES (5000e+0, 5000e+0);
+INSERT INTO t1(a,c) VALUES (-5000e+0, -5000e+0);
+SELECT * FROM t1;
+a	b	c
+9.999999000000000748	10	9.999
+1.225e-05	1.2e-05	1e-05
+0.0001225	0.00012	NULL
+0.122499999999999998	0.1225	NULL
+0.122587699999999994	0.12259	NULL
+12.25	12.25	NULL
+12.25	12.25	12.25
+122500	122500	NULL
+12250000000	1.2e+10	NULL
+1225000000000000	1.2e+15	NULL
+5000000	5000000	NULL
+1.25e+78	1.2e+78	NULL
+1.25e-94	1.2e-94	NULL
+1.25e+203	1e+203	NULL
+1.25e-175	1e-175	NULL
+1.225000000000000089	NULL	1.225
+1.370000000000000107	NULL	1.37
+-1.37	NULL	-1.37
+0.00187	NULL	0.002
+-0.0187	NULL	-0.01
+5000	NULL	5000
+-5000	NULL	-5000
+DROP TABLE t1;
+CREATE TABLE t (a CHAR(10),b INT);
+INSERT INTO t VALUES (),(),();
+INSERT INTO t(a) SELECT rand() FROM t;
+DROP TABLE t;
 End of 5.0 tests.
diff --git a/mysql-test/t/cast.test b/mysql-test/t/cast.test
index 316b79efe4d..fecb8677d51 100644
--- a/mysql-test/t/cast.test
+++ b/mysql-test/t/cast.test
@@ -177,8 +177,6 @@ select cast(1.0e+300 as signed int);
 CREATE TABLE t1 (f1 double);
 INSERT INTO t1 SET f1 = -1.0e+30 ;
 INSERT INTO t1 SET f1 = +1.0e+30 ;
-# Expected result is +-1e+30, but Windows returns +-1e+030.
---replace_result 1e+030 1e+30
 SELECT f1 AS double_val, CAST(f1 AS SIGNED INT) AS cast_val FROM t1;
 DROP TABLE t1;					   
 
diff --git a/mysql-test/t/insert.test b/mysql-test/t/insert.test
index 76177403bd0..cf67935768a 100644
--- a/mysql-test/t/insert.test
+++ b/mysql-test/t/insert.test
@@ -353,5 +353,86 @@ SELECT * FROM t2;
 
 DROP TABLE t1, t2;
 
+#
+# Bug #26788: mysqld (debug) aborts when inserting specific numbers into char
+#             fields
+#
+
+CREATE TABLE t1 (
+  a char(20) NOT NULL,
+  b char(7) DEFAULT NULL,
+  c char(4) DEFAULT NULL
+);
+
+INSERT INTO t1(a,b,c) VALUES (9.999999e+0, 9.999999e+0, 9.999e+0);
+INSERT INTO t1(a,b,c) VALUES (1.225e-05, 1.225e-05, 1.225e-05);
+INSERT INTO t1(a,b) VALUES (1.225e-04, 1.225e-04);
+INSERT INTO t1(a,b) VALUES (1.225e-01, 1.225e-01);
+INSERT INTO t1(a,b) VALUES (1.225877e-01, 1.225877e-01);
+INSERT INTO t1(a,b) VALUES (1.225e+01, 1.225e+01);
+INSERT INTO t1(a,b,c) VALUES (1.225e+01, 1.225e+01, 1.225e+01);
+INSERT INTO t1(a,b) VALUES (1.225e+05, 1.225e+05);
+INSERT INTO t1(a,b) VALUES (1.225e+10, 1.225e+10);
+INSERT INTO t1(a,b) VALUES (1.225e+15, 1.225e+15);
+INSERT INTO t1(a,b) VALUES (5000000e+0, 5000000e+0);
+INSERT INTO t1(a,b) VALUES (1.25e+78, 1.25e+78);
+INSERT INTO t1(a,b) VALUES (1.25e-94, 1.25e-94);
+INSERT INTO t1(a,b) VALUES (1.25e+203, 1.25e+203);
+INSERT INTO t1(a,b) VALUES (1.25e-175, 1.25e-175);
+INSERT INTO t1(a,c) VALUES (1.225e+0, 1.225e+0);
+INSERT INTO t1(a,c) VALUES (1.37e+0, 1.37e+0);
+INSERT INTO t1(a,c) VALUES (-1.37e+0, -1.37e+0);
+INSERT INTO t1(a,c) VALUES (1.87e-3, 1.87e-3);
+INSERT INTO t1(a,c) VALUES (-1.87e-2, -1.87e-2);
+INSERT INTO t1(a,c) VALUES (5000e+0, 5000e+0);
+INSERT INTO t1(a,c) VALUES (-5000e+0, -5000e+0);
+
+SELECT * FROM t1;
+
+DROP TABLE t1;
+
+CREATE TABLE t1 (
+  a char(20) NOT NULL,
+  b char(7) DEFAULT NULL,
+  c char(5)
+);
+
+
+INSERT INTO t1(a,b,c) VALUES (9.999999e+0, 9.999999e+0, 9.999e+0);
+INSERT INTO t1(a,b,c) VALUES (1.225e-05, 1.225e-05, 1.225e-05);
+INSERT INTO t1(a,b) VALUES (1.225e-04, 1.225e-04);
+INSERT INTO t1(a,b) VALUES (1.225e-01, 1.225e-01);
+INSERT INTO t1(a,b) VALUES (1.225877e-01, 1.225877e-01);
+INSERT INTO t1(a,b) VALUES (1.225e+01, 1.225e+01);
+INSERT INTO t1(a,b,c) VALUES (1.225e+01, 1.225e+01, 1.225e+01);
+INSERT INTO t1(a,b) VALUES (1.225e+05, 1.225e+05);
+INSERT INTO t1(a,b) VALUES (1.225e+10, 1.225e+10);
+INSERT INTO t1(a,b) VALUES (1.225e+15, 1.225e+15);
+INSERT INTO t1(a,b) VALUES (5000000e+0, 5000000e+0);
+INSERT INTO t1(a,b) VALUES (1.25e+78, 1.25e+78);
+INSERT INTO t1(a,b) VALUES (1.25e-94, 1.25e-94);
+INSERT INTO t1(a,b) VALUES (1.25e+203, 1.25e+203);
+INSERT INTO t1(a,b) VALUES (1.25e-175, 1.25e-175);
+INSERT INTO t1(a,c) VALUES (1.225e+0, 1.225e+0);
+INSERT INTO t1(a,c) VALUES (1.37e+0, 1.37e+0);
+INSERT INTO t1(a,c) VALUES (-1.37e+0, -1.37e+0);
+INSERT INTO t1(a,c) VALUES (1.87e-3, 1.87e-3);
+INSERT INTO t1(a,c) VALUES (-1.87e-2, -1.87e-2);
+INSERT INTO t1(a,c) VALUES (5000e+0, 5000e+0);
+INSERT INTO t1(a,c) VALUES (-5000e+0, -5000e+0);
+
+SELECT * FROM t1;
+
+DROP TABLE t1;
+
+#
+# Bug #31152: assertion in Field_str::store(double)
+#
+
+CREATE TABLE t (a CHAR(10),b INT);
+INSERT INTO t VALUES (),(),();
+INSERT INTO t(a) SELECT rand() FROM t;
+DROP TABLE t;
+
 --echo End of 5.0 tests.
 
diff --git a/mysql-test/t/type_float.test b/mysql-test/t/type_float.test
index a55200c8853..f67a1b1719b 100644
--- a/mysql-test/t/type_float.test
+++ b/mysql-test/t/type_float.test
@@ -116,15 +116,10 @@ drop table if exists t1;
 # Check conversion of floats to character field (Bug #7774)
 create table t1 (c char(20));
 insert into t1 values (5e-28);
-# Expected result is "5e-28", but windows returns "5e-028"
---replace_result 5e-028 5e-28
 select * from t1;
 drop table t1;
 create table t1 (c char(6));
 insert into t1 values (2e5),(2e6),(2e-4),(2e-5);
-# Expected result is "2e+06", but windows returns "2e+006"
-# Expected result is "2e-05", but windows returns "2e-005"
---replace_result 2e+006 2e+06 2e-005 2e-05
 select * from t1;
 drop table t1;
 
diff --git a/mysql-test/t/variables.test b/mysql-test/t/variables.test
index 0ad85a32568..4b78ea6c026 100644
--- a/mysql-test/t/variables.test
+++ b/mysql-test/t/variables.test
@@ -51,8 +51,6 @@ select @test, @`test`, @TEST, @`TEST`, @"teSt";
 set @select=2,@t5=1.23456;
 select @`select`,@not_used;
 set @test_int=10,@test_double=1e-10,@test_string="abcdeghi",@test_string2="abcdefghij",@select=NULL;
-# Expected result "1e-10", windows returns "1e-010"
---replace_result 1e-010 1e-10
 select @test_int,@test_double,@test_string,@test_string2,@select;
 set @test_int="hello",@test_double="hello",@test_string="hello",@test_string2="hello";
 select @test_int,@test_double,@test_string,@test_string2;
diff --git a/sql/field.cc b/sql/field.cc
index 8191d885a27..c604f04339c 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -5907,24 +5907,70 @@ int Field_str::store(double nr)
 {
   char buff[DOUBLE_TO_STRING_CONVERSION_BUFFER_SIZE];
   uint length;
-  bool use_scientific_notation= TRUE;
   uint local_char_length= field_length / charset()->mbmaxlen;
-  /*
-    Check fabs(nr) against longest value that can be stored in field,
-    which depends on whether the value is < 1 or not, and negative or not
-  */
   double anr= fabs(nr);
   int neg= (nr < 0.0) ? 1 : 0;
-  if (local_char_length > 4 && local_char_length < 32 &&
-      (anr < 1.0 ? anr > 1/(log_10[max(0,(int) local_char_length-neg-2)]) /* -2 for "0." */
-                 : anr < log_10[local_char_length-neg]-1))
-    use_scientific_notation= FALSE;
-
-  length= (uint) my_sprintf(buff, (buff, "%-.*g",
-                                   (use_scientific_notation ?
-                                    max(0, (int)local_char_length-neg-5) :
-                                    local_char_length),
-                                   nr));
+  uint max_length;
+  int exp;
+  uint digits;
+  uint i;
+
+  /* Calculate the exponent from the 'e'-format conversion */
+  if (anr < 1.0 && anr > 0)
+  {
+    for (exp= 0; anr < 1e-100; exp-= 100, anr*= 1e100);
+    for (; anr < 1e-10; exp-= 10, anr*= 1e10);
+    for (i= 1; anr < 1 / log_10[i]; exp--, i++);
+    exp--;
+  }
+  else
+  {
+    for (exp= 0; anr > 1e100; exp+= 100, anr/= 1e100);
+    for (; anr > 1e10; exp+= 10, anr/= 1e10);
+    for (i= 1; anr > log_10[i]; exp++, i++);
+  }
+
+  max_length= local_char_length - neg;
+
+  /*
+    Since in sprintf("%g") precision means the number of significant digits,
+    calculate the maximum number of significant digits if the 'f'-format
+    would be used (+1 for decimal point if the number has a fractional part).
+  */
+  digits= max(0, (int) max_length - (nr != trunc(nr)));
+  /*
+    If the exponent is negative, decrease digits by the number of leading zeros
+    after the decimal point that do not count as significant digits.
+  */
+  if (exp < 0)
+    digits= max(0, (int) digits + exp);
+  /*
+    'e'-format is used only if the exponent is less than -4 or greater than or
+    equal to the precision. In this case we need to adjust the number of
+    significant digits to take "e+NN" + decimal point into account (hence -5).
+    We also have to reserve one additional character if abs(exp) >= 100.
+  */
+  if (exp >= (int) digits || exp < -4)
+    digits= max(0, (int) (max_length - 5 - (exp >= 100 || exp <= -100)));
+  
+  length= (uint) my_sprintf(buff, (buff, "%-.*g", digits, nr));
+
+#ifdef __WIN__
+  /*
+    Windows always zero-pads the exponent to 3 digits, we want to remove the
+    leading 0 to match the sprintf() output on other platforms.
+  */
+  if ((exp >= (int) digits || exp < -4) && exp > -100 && exp < 100)
+  {
+    DBUG_ASSERT(length >= 6); /* 1e+NNN */
+    uint tmp= length - 3;
+    buff[tmp]= buff[tmp + 1];
+    tmp++;
+    buff[tmp]= buff[tmp + 1];
+    length--;
+  }
+#endif
+  
   /*
     +1 below is because "precision" in %g above means the
     max. number of significant digits, not the output width.