babelfish-for-postgresql / babelfish_extensions / 11831695974

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push

github

Committed by web-flow

Commit Message

Support for T-SQL variable/parameter names like @@var and @var# (#3073)

Valid names of user-defined T-SQL variables and/or parameters are @@myvar, @myvar#, @#myvar, etc. and indeed we see customer T-SQL applications using such names.
Until now, such names have raised errors in the backend because we can only handle variable/parameter names with one leading @ and without # characters.
This fix adds support by enclosing such variable names in square bracket delimiters; when using double quotes as delimiters (as is currently done in most places for regular-named variables), a query like select @@V will produce the string '@@V' instead of the value of variable @@V.
The fix is partly done through ANTLR rewriting and partly at execution time elsewhere in the babelfish_tsql codeline. Things are complicated by the fact that the ANTLR rewriting logic is very fragmented, as well as that for some variables reference contexts inside the body of a procedure or trigger, rewriting must be postponed until the body is executed. This means there are multiple code paths where these variable names must be intercepted.
This fix also addresses variable names in some contexts (like a cursor variable) that previously could not be longer than 63 characters.
This fix also solves the previous issue that a variable could be declared with a name matching an internal sys function, but was resolved as the intern function instead of the variable, i.e. DECLARE @@RAND INT=123 SELECT @@RAND would return a random number instead of 123.

Issues Resolved: 
BABEL-2481 Parameter declarations containing # characters not handled correctly
BABEL-476 Support local variables/parameters with multiple '@' characters
BABEL-5384 User-defined @@variable should not be mapped to sys function

Signed-off-by: Rob Verschoor rcv@amazon.com

Run Details

283 of 292 new or added lines in 6 files covered. (96.92%)

19 existing lines in 3 files now uncovered.

45632 of 61070 relevant lines covered (74.72%)

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