D29327: Improve a bit parse error dignosis

[jordi fita i mas]

jfita created this revision.
jfita added reviewers: staniek, piggz.
Herald added a project: KDb.
Herald added a subscriber: Kexi-Devel-list.
jfita requested review of this revision.

REVISION SUMMARY
  Currently, the parse error message for a query like
  
    SELECT select #1/1a/2020#;
  
  is
  
    org.kde.kdb.core: Parse error: tokens left globalCurrentPos: 18 sql.length(): 19 globalToken: ";"
    org.kde.kdb.core: error:
    org.kde.kdb.core: at character  18  near tooken  ";"
  
  and Kexi, in SQL text mode, moves the cursor next to the semicolon.
  
  The query is indeed incorrect, but the error message is misleading
  because the error is in the “a” within the date literal, not the
  terminating semicolon.
  
  This is due the lack of a “fallback” rule within the DATE_OR_TIME start
  condition and, because it is an exclusive condition, Flex provides its
  default rule that returns nothing to the parser. Therefore, the
  globalCurrentPos is not incremented and, at the end, KDbParser can
  detect something went wrong, but can not pinpoint the error’s correct
  location at that stage.
  
  I added a new rule that simply returns any other non-recognized
  character to the parser so that it can detect the erroneous input and
  present a more accurate position of where the error is. With that change
  Kexi moves the cursor next to the “a”.
  
  I also changed the last rule of the INITIAL start condition to match any
  character, because otherwise it also reports the error at the position
  of the semicolon in queries like the following:
  
    SELECT 1' FROM input;
  
  There was, however, another issue with Flex’s action for its default
  rule: it calls the ECHO macro that, by default, is defined as write the
  matched input to stdout.
  
  This is not a problem for Kexi — in fact, i am unable to see that write
  in the console —, but it messes up the output of SqlParseTest. This is
  particularly important when called with the ‘-xml’ or ‘-tap’ parameters,
  that need to maintain their strict format or then QtCreator or Perl’s
  prove can not parse the output.
  
  FIXED-IN:3.2.1

REPOSITORY
  R15 KDb

BRANCH
  3.2

REVISION DETAIL
  https://phabricator.kde.org/D29327

AFFECTED FILES
  src/parser/KDbSqlScanner.l
  src/parser/generated/sqlscanner.cpp

To: jfita, staniek, piggz
Cc: Kexi-Devel-list, barman, wicik, staniek
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