Review Request: PIG-2248 Pig parser does not detect when a macro name masks a UDF name

[Johnny Zhang]

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https://reviews.apache.org/r/10435/
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Review request for pig.


Description
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Pig accepts a macro like:
define COUNT(in_relation, min_gpa) returns c {
                           b = filter $in_relation by gpa >= $min_gpa;
                           $c = foreach b generate age, name;
                       }
This should produce a warning that it is masking a UDF.


This addresses bug PIG-2248.
    https://issues.apache.org/jira/browse/PIG-2248


Diffs
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  src/org/apache/pig/parser/PigMacro.java 435fc13 

Diff: https://reviews.apache.org/r/10435/diff/


Testing
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I tested it with two macro defined in one Pig script, there is only one warning 
message for each macro. The message looks like
[main] WARN  org.apache.pig.parser.PigMacro - macro name 'COUNT' masks a 
builtin UDF org.apache.pig.builtin.COUNT
[main] WARN  org.apache.pig.parser.PigMacro - macro name 'ABS' masks a builtin 
UDF org.apache.pig.builtin.ABS


Thanks,

Johnny Zhang