PDO: Migrate maxlen of pdo_column_data from size_t to zend_long

[marc-mabe]

This is returned in PDOStatement::getColumnMeta as len documented as "The length of this column. Normally -1 for types other than floating point decimals."

Also, It was as FIXME already.

• pgsql: PQfsize: returns the space allocated for this column in a database row, in other words the size of the server's internal representation of the data type. (Accordingly, it is not really very useful to clients.) A negative value indicates the data type is variable-length.
• dblib: dbcollen: The maximum length, in bytes, of the data for the particular column. If the column number is not in range, dbcollen returns -1.
• firebird: XSQLVAR.sqllen -> ISC_SHORT -> signed short: length of data area
• mysql: MYSQL_FIELD.length
  • MYSQLND_FIELD.length -> zend_ulong: Width of column (create length)
  • libmysql: unsigned long length : Width of column (create length)

I noticed this during my work of 64bit integers on 32bit arch where it would was failing: https://github.com/php/php-src/actions/runs/16311803646/job/46068812948#step:9:2782

[Girgias]

Wouldn't this be more accurate?

Suggested change

	zend_long maxlen;
	ssize_t maxlen;

[SakiTakamachi]

Hmm... It seems that in pdo_odbc, a ulong value is passed here (according to the ODBC specification, an unsigned 64-bit integer might be passed).

php-src/ext/pdo_odbc/odbc_stmt.c

Line 614 in eaf24ba

col->maxlen = S->cols[colno].datalen = colsize;

I suppose such columns are quite rare in practice, but this does introduce a slight possibility of a BC break.

One alternative might be to add a flag instead of changing the type to signed.

What do you think? @NattyNarwhal

[NattyNarwhal]

Already the situation in odbc_stmt_describe is confusing because it's setting SQLULEN colsize from SQLLEN displaysize. It's also not using the pre-displaysize colsize for anything other than to check if it's a long column. So at least from the PDO_ODBC perspective, it'd make sense to be a signed size type for the column size (and for PDO_ODBC to maybe to use displaysize directly instead of the possible confusion setting it to a different signedness type).

[marc-mabe]

I see maxlen used only in getColumnMeta where it gets reported as PHP int and nowhere else internally.

[marc-mabe]

@SakiTakamachi @NattyNarwhal How should I proceed here? Any suggestions?

[NattyNarwhal]

I'd say this looks fine, though you may want to check Gina's suggestion. The issue in PDO_ODBC existed before this; it'd be good to fix that so it presumably uses the signed displaysize directly, but your call if you want to fix it in this PR.

[marc-mabe]

@NattyNarwhal I have updated the PR to set maxlen = displaysize directly and S->cols[colno].datalen = colsize.

I hope this is fine for this PR as I'm not an ODBC user and my goal is reduce the changes needed in #19079 by splitting out what makes sense.

[NattyNarwhal]

I think this makes sense (at least w/ ODBC).