When trying to show "conversion error", "arithmetic exception/string truncation" may appear instead, misleading the user [CORE2001]

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Submitted by: Claudio Valderrama C. (robocop)

Assigned to: Claudio Valderrama C. (robocop)

Is related to QA354

This is a case of one error causing another.
When FB is asked to convert one data type to another, it may not always succeed. This is the case with explicit user requests (a string that doesn't hold a date is casted to date) or internal conversion from UDF results (the UDF's dynamically returned type doesn't match the declared type), etc.
However, due to the way the conversion error message is produced, it may cause a string truncation when trying to assemble the error message. Therefore, the client application receives "string truncation" instead of "conversion error". Example:

1.- This is correct:
SQL> select cast('1995' as date) from rdb$database;

   CAST

===========
Statement failed, SQLSTATE = 22018
conversion error from string "1995"

2.- This is misleading:
SQL> select cast('1995-12-2444444444444444444444444444444' as date) from rdb$database;

   CAST

===========
Statement failed, SQLCODE = -802
arithmetic exception, numeric overflow, or string truncation

3.- This is the fix when the source string is too long to report it or try to convert it:
SQL> select cast('1995-12-2444444444444444444444444444444' as date) from rdb$database;

   CAST

===========
Statement failed, SQLSTATE = 22018
conversion error from string "<Too long string or can't be translated>"

Another solution would be to take a substring of the original string.

Commits: bb672a9

[firebird-automations]

Modified by: Claudio Valderrama C. (robocop)

assignee: Claudio Valderrama C. [ robocop ]

[firebird-automations]

Modified by: Claudio Valderrama C. (robocop)

status: Open [ 1 ] => Resolved [ 5 ]

resolution: Fixed [ 1 ]

Fix Version: 2.5 Beta 1 [ 10251 ]

[firebird-automations]

Modified by: @pcisar

Link: This issue is related to QA354 [ QA354 ]

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Commented by: @pcisar

QA test added.

[firebird-automations]

Modified by: @pcisar

status: Resolved [ 5 ] => Closed [ 6 ]

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Modified by: @pavel-zotov

QA Status: No test

[firebird-automations]

Modified by: @pavel-zotov

QA Status: No test => Done successfully