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Oracle: Init parameter PLSQL_WARNINGS

The value of plsql_warnings controls for each of the three PL/SQL warning categories if they're reported when they are encountered when a PL/SQL object is compiled.
Enable all warnings except PLW-06009: procedure "…" OTHERS handler does not end in RAISE or RAISE_APPLICATION_ERROR.
Warn about unreachable code: 
alter session set plsql_warnings = 'enable:(6002)';
Treat the warning package specification exposes global variable as error: 
alter session set plsql_warnings = 'error:(6026)';
Disable all warnings: 
alter session set plsql_warnings = 'disable:all';

See also

The value of plsql_warnings that was in effect when a PL/SQL object was compiled can be queried from dba_plsql_object_settings.
Errors and warnings in PL/SQL.
user_errors / all_errors / dba_errors / cdb_errors
The SQL*Plus warning SP2-0804: Procedure created with compilation warnings.
init parameters

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