Fix an offense creation for Lint/EmptyFile

[fatkodima]

Closes #8669

[bbatsov]

Can you explain why those changes are needed? Personally, I don't quite get it.

[marcandre]

I thought the HTML formatter was the culprit (or maybe even my rewriter code)

[fatkodima]

The original code

range = source_range(processed_source.buffer, 1, 0)		
add_offense(range)

adds an offense to non existent (empty) source range - 1st line, 0-th column.
When generating html report (I didn't tested, but this can be a problem for other formatters), this https://github.com/rubocop-hq/rubocop/blob/9bc7908b1ad171b33ede24908acced724db6e8d4/lib/rubocop/formatter/html_formatter.rb#L118-L126

119 and 124 lines fails here

https://github.com/whitequark/parser/blob/c25585d8d91f3470d9cdfd6f3b6a553ad9a809fb/lib/parser/source/buffer.rb#L269-L271

because of fetch on empty source_lines.

add_global_offense adds a global offense, roughly speaking, not attached to any specific location and overrides source_line to empty string, so this eliminates the problem.

[bbatsov]

Got it. Might be nice to integrate those global offenses with expect_offence, though, as I'm certain people will wonder why are the tests using it.

[fatkodima]

Might be nice to integrate those global offenses with expect_offence

syntax_spec.rb uses the same style, as this test file, so also needs an update.
Wdyt about introducing it in a separate PR?

[marcandre]

I think:

source_range(processed_source.buffer, 1, 0)
# should be
source_range(processed_source.buffer, 1, 0, 0)	

FWIW, this helper is terrible. There are too many of these multiple argument public methods... The cop in charge of that should really have different settings for private (I don't care much, really) and public (should be max 1 imo).

If you prefer to go the add_global_offense route (seems a bit more complicated), I think the odd spec is fine. add_global_offense was really meant for non-parseable files tbh.

[fatkodima]

source_range(processed_source.buffer, 1, 0, 0)

Just tested, the same error as in the original issue.

[bbatsov]

Well, I guess the suggested fix will do for now. Thanks!