Good catch. Yes, we want to stay on top of these kinds of warnings. (See broken windows theory [1].) Probably introduced by https://issues.apache.org/jira/browse/CALCITE-5450. Probably missing one or two LOOKAHEAD directives in the parser. Can you log a JIRA case please.
Julian [1] https://en.wikipedia.org/wiki/Broken_windows_theory On Fri, Jan 27, 2023 at 9:50 AM Alessandro Solimando <alessandro.solima...@gmail.com> wrote: > > Hello everyone, > while checking CI logs I have noticed that we have lots of JavaCC warnings > related to ambiguous prefixes in the productions of one of our grammars. > > They also seem related to time functions, for which I have seen several > related developments for BigQuery lately. > > Have we verified that our grammar is still behaving properly under this > situation? Have we considered increasing the lookahead value as suggested? > Shall we open a Jira ticket to have a closer look? > > Here is an example of CI logs showing the problem (although it is > reproducible locally): > https://ci-builds.apache.org/job/Calcite/job/Calcite-sonar/job/main/18/consoleFull > > > In what follows the extract that is relevant to the discussion at hand: > > > > Task :core:javaCCMain > > Java Compiler Compiler Version 4.0 (Parser Generator) > > (type "javacc" with no arguments for help) > > Reading from file > > /home/jenkins/jenkins-agent/workspace/Calcite_Calcite-sonar_main/core/build/fmpp/fmppMain/javacc/Parser.jj > > . . . > > Warning: Output directory > > "/home/jenkins/jenkins-agent/workspace/Calcite_Calcite-sonar_main/core/build/javacc/javaCCMain/org/apache/calcite/sql/parser/impl" > > does not exist. Creating the directory. > > Note: UNICODE_INPUT option is specified. Please make sure you create the > > parser/lexer using a Reader with the correct character encoding. > > Warning: Choice conflict involving two expansions at > > line 4930, column 5 and line 4956, column 5 respectively. > > A common prefix is: "MICROSECOND" > > Consider using a lookahead of 2 for earlier expansion. > > Warning: Choice conflict involving two expansions at > > line 4931, column 5 and line 4956, column 5 respectively. > > A common prefix is: "MILLISECOND" > > Consider using a lookahead of 2 for earlier expansion. > > Warning: Choice conflict involving two expansions at > > line 4936, column 5 and line 4956, column 5 respectively. > > A common prefix is: "DOW" > > Consider using a lookahead of 2 for earlier expansion. > > Warning: Choice conflict involving two expansions at > > line 4937, column 5 and line 4956, column 5 respectively. > > A common prefix is: "DOY" > > Consider using a lookahead of 2 for earlier expansion. > > Warning: Choice conflict involving two expansions at > > line 4938, column 5 and line 4956, column 5 respectively. > > A common prefix is: "ISODOW" > > Consider using a lookahead of 2 for earlier expansion. > > Warning: Choice conflict involving two expansions at > > line 4939, column 5 and line 4956, column 5 respectively. > > A common prefix is: "ISOYEAR" > > Consider using a lookahead of 2 for earlier expansion. > > Warning: Choice conflict involving two expansions at > > line 4940, column 5 and line 4956, column 5 respectively. > > A common prefix is: "WEEK" > > Consider using a lookahead of 2 for earlier expansion. > > Warning: Choice conflict involving two expansions at > > line 4950, column 5 and line 4956, column 5 respectively. > > A common prefix is: "QUARTER" > > Consider using a lookahead of 2 for earlier expansion. > > Warning: Choice conflict involving two expansions at > > line 4952, column 5 and line 4956, column 5 respectively. > > A common prefix is: "EPOCH" > > Consider using a lookahead of 2 for earlier expansion. > > Warning: Choice conflict involving two expansions at > > line 4953, column 5 and line 4956, column 5 respectively. > > A common prefix is: "DECADE" > > Consider using a lookahead of 2 for earlier expansion. > > Warning: Choice conflict involving two expansions at > > line 4954, column 5 and line 4956, column 5 respectively. > > A common prefix is: "CENTURY" > > Consider using a lookahead of 2 for earlier expansion. > > Warning: Choice conflict involving two expansions at > > line 4955, column 5 and line 4956, column 5 respectively. > > A common prefix is: "MILLENNIUM" > > Consider using a lookahead of 2 for earlier expansion. > > Warning: Choice conflict involving two expansions at > > line 6549, column 9 and line 6551, column 9 respectively. > > A common prefix is: "WEEK" "(" > > Consider using a lookahead of 3 or more for earlier expansion. > > File "TokenMgrError.java" does not exist. Will create one. > > File "ParseException.java" does not exist. Will create one. > > File "Token.java" does not exist. Will create one. > > File "SimpleCharStream.java" does not exist. Will create one. > > Parser generated with 0 errors and 14 warnings. > > > Best regards, > Alessandro
