Submitted by: @dyemanov

Is related to QA566

Test case:

SELECT LIST(F, '')
FROM (
SELECT CAST(ASCII_CHAR(0XFF) AS BLOB SUB_TYPE 0) AS F
FROM RDB$DATABASE
UNION ALL
SELECT CAST(ASCII_CHAR(0XDE) AS BLOB SUB_TYPE 0) AS F
FROM RDB$DATABASE
)

returns 0x2E2E instead of the expected 0xFFDE. Internally the contents is treated as text and thus gets corrected by the blob filter (non-ASCII characters are replaced with dots).

The plain concatenation works correctly though:

SELECT CAST(ASCII_CHAR(0XFF) AS BLOB SUB_TYPE 0) || CAST(ASCII_CHAR(0XDE) AS BLOB SUB_TYPE 0)
FROM RDB$DATABASE

returns 0xFFDE.

Commits: 6987232