[pkg/ottl] Parsing of named arguments is whitespace dependent

[TylerHelmuth]

Component(s)

pkg/ottl

What happened?

Description

While testing out some optional parameter situations I discovered that the named argument parsing is whitespace dependent. This is in contrast with the rest of OTTL which does not depend on whitespace. I am not yet sure why this is happening as the grammar/tokens seem correct. The whitespace in (@(Lowercase(Uppercase | Lowercase)*) Equal)? is ignored by the parser and the Equal token cannot appear in Lowercase or Uppercase.

Steps to Reproduce

I added this test to parser_test.go:

{
  name:      "editor with named arg",
  statement: `set(name="foo")`,
  expected: &parsedStatement{
    Editor: editor{
      Function: "set",
      Arguments: []argument{
        {
          Name: "name",
          Value: value{
            String: ottltest.Strp("foo"),
          },
        },
      },
    },
    WhereClause: nil,
  },
},

Expected Result

Test passed

Actual Result

Got an error parsing the statement. No error occurs if the statement is written as set(name = "foo")

[TylerHelmuth]

Additional testing revealed that set(name= "foo") passed

[TylerHelmuth]

Turns out that the Equal token is the issue. In order to not match ==, the token is written as =[^=], which means that it must have at least 1 character after the equal.