sqlite3_bind_bug68849 fail on x86 with sqlite 3.43

[andypost]

Description

The test ext/sqlite3/tests/sqlite3_bind_bug68849.phpt fail on x86 arch (32-bits)

Previous build (8.2.10RC1) passed but sqlite was 3.42.0 (current is 3.43.0)

The same test failed building PHP 8.3RC1 so very probably precision somehow affected

========DIFF========
--
       ["b"]=>
       string(5) "hello"
       ["c"]=>
[1;32m007+   float(3.1399999999999997)[0m
[1;31m007-   float(3.14)[0m
     }
     array(3) {
       ["a"]=>
--
       ["b"]=>
       string(5) "hello"
       ["c"]=>
[1;32m015+   float(3.1399999999999997)[0m
[1;31m015-   float(3.14)[0m
     }
     array(3) {
       ["a"]=>
--
       ["b"]=>
       string(2) "42"
       ["c"]=>
[1;32m023+   float(0.42000000000000004)[0m
[1;31m023-   float(0.42)[0m
     }
     array(3) {
       ["a"]=>
--
========DONE========

Refs

• https://gitlab.alpinelinux.org/alpine/aports/-/merge_requests/50091
• https://gitlab.alpinelinux.org/alpine/aports/-/merge_requests/50709

PHP Version

PHP 8.1.22, 8.2.9, 8.3.0RC1

Operating System

Alpinelinux

[andypost]

Confirm it fails on 8.1.22 too when sqlite3 is 3.43.0

[SakiTakamachi]

I did a little research on this issue.
I have prepared 3 containers with docker.

1. 32bit Alpine, Sqlite3.42
2. 32bit Alpine, Sqlite3.43
3. 64bit Alpine, Sqlite3.43

Among these, only "2" is reproduced, however, a little more research revealed something strange.
When executing only the select statement using the sqlite DB file created and inserted in the "2" environment in the other two environments, the same result as "2" was obtained.
Conversely, if the DB file created and inserted in "1, 3" is used in "2", the result will be normal.

From this it at least appears that the problem is occurring with writes rather than reads.

[SakiTakamachi]

I tried following these steps:

32bit Alpine, Sqlite3.43

Create a table from php and insert it:

# php test.php

<?php

$db = new SQLite3('sq');

$db->exec("CREATE TABLE test (id int, value REAL);" .
        "INSERT INTO test VALUES (1, 3.14);"
);

Insert directly from sqlite:

# sqlite sq
sqlite> INSERT INTO test VALUES (2, 3.14);

Check the data from sqlite:

sqlite> select * from test;
1|3.14
2|3.14

sqlite> SELECT (SELECT value FROM test WHERE id = 1) == (SELECT value FROM test WHERE id = 2);
0

Check data from php:

<?php

$db = new SQLite3('sq');

$s = $db->prepare('SELECT * FROM test WHERE id = ?;');
$s->bindValue(1, 1);
$r = $s->execute();
var_dump($r->fetchArray(SQLITE3_ASSOC));

$s = $db->prepare('SELECT * FROM test WHERE id = ?;');
$s->bindValue(1, 2);
$r = $s->execute();
var_dump($r->fetchArray(SQLITE3_ASSOC));

array(2) {
  ["id"]=>
  int(1)
  ["value"]=>
  float(3.1399999999999997)
}
array(2) {
  ["id"]=>
  int(2)
  ["value"]=>
  float(3.14)
}

I currently have no idea why this is happening.

[SakiTakamachi]

Oops.....

create table test (lang text, value real);

write.rb

#!/usr/bin/ruby

require 'sqlite3'

db = SQLite3::Database.new('sq')
db.execute("INSERT INTO test VALUES ('ruby', 3.14);")
db.close

write.php

<?php

$db = new SQLite3('sq');
$db->exec("INSERT INTO test VALUES ('php', 3.14);");
$db->close();

ruby write.rb
php write.php

result:

array(2) {
  ["lang"]=>
  string(4) "ruby"
  ["value"]=>
  float(3.14)
}
array(2) {
  ["lang"]=>
  string(3) "php"
  ["value"]=>
  float(3.1399999999999997)
}

[andypost]

One more mysterious detail - it fails only on x86 32-bits, on armv7 and armhf arches (32-bits too) it passed(

[SakiTakamachi]

Using a prepared statement and binding the value gives us 3.14.

Maybe there is something wrong with the zval string?

I haven't done any research yet, so I'm guessing...

[SakiTakamachi]

Apparently ruby ​​uses prepared statements inside execute.

It was a bit premature to assume that php was the cause.

Looks like I need to investigate a little more carefully.

[SakiTakamachi]

I might have gotten some hints.
Even using prepared statements, the results could sometimes be corrupted.

When passing a value as a string:

$s->bindValue(1, '3.14');

or

$s->bindValue(1, 3.14, SQLITE3_TEXT);

// result
float(3.1399999999999997)

When passing a value as a float:

$s->bindValue(1, 3.14);

or

$s->bindValue(1, '3.14', SQLITE3_FLOAT);

//result
float(3.14)

[andypost]

So default is SQLITE3_TEXT which means that it's sqlite issue when text casted to float?

[SakiTakamachi]

I feel that way too.

However, unless you establish a reproduction procedure that excludes PHP or identify the source code that is causing the problem, it will be difficult to get the SQLite side to acknowledge the problem.

So we need to somehow establish a reproducible procedure.

[SakiTakamachi]

I currently have no idea why this is happening.....
I mention this to avoid any unnecessary worries, but all of these tests were performed in the same docker container.

php:

<?php

$db = new SQLite3('sq');

$s = $db->prepare('SELECT ? == CAST((SELECT CAST(? as TEXT)) as REAL);');
$s->bindValue(1, 3.14);
$s->bindValue(2, 3.14);
$r = $s->execute();
var_dump($r->fetchArray(SQLITE3_ASSOC));

// result
array(1) {
  ["? == CAST((SELECT CAST(? as TEXT)) as REAL)"]=>
  int(0)
}

ruby:

#!/usr/bin/ruby

require 'sqlite3'

db = SQLite3::Database.new('sq')

s = db.prepare("SELECT ? == CAST((SELECT CAST(? as TEXT)) as REAL);")
s.bind_param(1, 3.14)
s.bind_param(2, 3.14)
s.execute().each do |row|
    p row
end

// result
[1]

python:

import sqlite3

db = sqlite3.connect('sq')
cur = db.cursor()

cur.execute('SELECT ? == CAST((SELECT CAST(? as TEXT)) as REAL);', (3.14, 3.14))

print(cur.fetchall())

// result
[(1,)]

cli:

sqlite> SELECT 3.14 == CAST((SELECT CAST(3.14 as TEXT)) as REAL);
1

At least in this case, only php has broken results.
I'm starting to think about the possibility that the sqlite API being called is using an outdated one.

[SakiTakamachi]

I wrote C and tried inserting it so that the conditions are almost the same as when using php's sqlite3.
Unfortunately, it doesn't seem to break in this case.

#include <stdio.h>
#include <sqlite3.h>

int main() {
    sqlite3* db;
    sqlite3_open_v2("sq", &db, 0x00000002 | 0x00000004, NULL);

    sqlite3_exec(
        db,
        "INSERT INTO test VALUES ('c', 3.14);",
        NULL,
        NULL,
        NULL
    );

    sqlite3_close(db);

    return 0;
}

php read result:

array(2) {
  ["lang"]=>
  string(1) "c"
  ["value"]=>
  float(3.14)
}