Error parsing C-style strings

[benjie]

PostgreSQL supports C-style string escaping in E'' strings:

https://www.postgresql.org/docs/current/sql-syntax-lexical.html#SQL-SYNTAX-STRINGS-ESCAPE

e.g.:

# select E'\'' as example;
 example
---------
 '
(1 row)

Time: 0.241 ms

However pg-minify v1.0.0 (and v0.5.5) baulks at this:

> m = require('pg-minify')
[Function: minify] {
  SQLParsingError: [Function: SQLParsingError],
  parsingErrorCode: {
    unclosedMLC: 0,
    unclosedText: 1,
    unclosedQI: 2,
    multiLineQI: 3,
    nestedMLC: 4
  }
}
> m("select E'\'' as example;")
Thrown:
SQLParsingError: 1
    at new SQLParsingError (/Users/benjiegillam/Dev/graphile-migrate/node_modules/pg-minify/lib/error.js:25:24)
    at throwError (/Users/benjiegillam/Dev/graphile-migrate/node_modules/pg-minify/lib/parser.js:177:15)
    at minify (/Users/benjiegillam/Dev/graphile-migrate/node_modules/pg-minify/lib/parser.js:113:17)
    at repl:1:1
    at Script.runInThisContext (vm.js:123:20)
    at REPLServer.defaultEval (repl.js:358:29)
    at bound (domain.js:415:14)
    at REPLServer.runBound [as eval] (domain.js:428:12)
    at REPLServer.onLine (repl.js:665:10)
    at REPLServer.emit (events.js:201:15) {
  name: 'SQLParsingError',
  stack: 'SQLParsingError: 1\n    at new SQLParsingError ' +
    '(/Users/benjiegillam/Dev/graphile-migrate/node_modules/pg-minify/lib/error.js:25:24)\n' +
    '    at throwError ' +
    '(/Users/benjiegillam/Dev/graphile-migrate/node_modules/pg-minify/lib/parser.js:177:15)\n' +
    '    at minify ' +
    '(/Users/benjiegillam/Dev/graphile-migrate/node_modules/pg-minify/lib/parser.js:113:17)\n' +
    '    at repl:1:1\n    at Script.runInThisContext (vm.js:123:20)\n    at ' +
    'REPLServer.defaultEval (repl.js:358:29)\n    at bound ' +
    '(domain.js:415:14)\n    at REPLServer.runBound [as eval] ' +
    '(domain.js:428:12)\n    at REPLServer.onLine (repl.js:665:10)\n    at ' +
    'REPLServer.emit (events.js:201:15)',
  code: 1,
  error: 'Unclosed text block.',
  position: { line: 1, column: 9 },
  message: 'Error parsing SQL at {line:1,col:9}: Unclosed text block.'
}
>

[vitaly-t]

Yes, this seems like a special case that's not supported at the moment.

The library expects that \' is escaped as '', which then works.

It will require some tweaking to make the reported case work also.

[vitaly-t]

I'm trying to come up with a RegEx that would help me skip those special cases, without complicating the algorithm further. I had to open a question on StackOverflow for it, as I got stuck with such a RegEx.

We just need to skip every ' that's preceded by an odd number of \.

[vitaly-t]

Fixed in v1.1.0, and in much a simpler way, without any RegEx.

@benjie Thanks for reporting!

[vitaly-t]

@benjie Release 1.2.0 now makes this library way better.