Check symlink outside site_source without Pathutil

[ashmaroli]

• This is a 🔨 code refactoring.

Summary

pathutil gem appears to be unmaintained.
Therefore, emulate its existing use in lib/jekyll/entry_filter.rb using Ruby's built-in methods.

Test Coverage

Relies on existing test defined as:

jekyll/test/test_entry_filter.rb

Lines 89 to 93 in e695c1e

	should "filter symlink pointing outside site source" do
	ent1 = %w(_includes/tmp)
	entries = EntryFilter.new(@site).filter(ent1)
	assert_equal %w(), entries
	end

[parkr]

LGTM, I thought of an alternative for you to consider but your original solution is likely still best.

[parkr]

One alternative here might be to check if a constructed path and the real path are not equal?

site.in_source_dir(entry) != File.realpath(entry)

[ashmaroli]

The downside to this is that it results in consumption of additional resources.
site.in_source_dir(entry) is more expensive (both in terms of allocations and cpu) than site.in_source_dir.

A better alternative to my original proposal here would be to check directly against site.source instead:

Suggested change

	!File.realpath(entry).start_with?(site.in_source_dir)
	!File.realpath(entry).start_with?(site.source)

But since EntryFilter#symlink_outside_site_source? method is mostly invoked only if site.safe && File.symlink?(entry) returns true, the difference between site.source and site.in_source_dir is negligible.

[parkr]

Sounds good.

[ashmaroli]

@jekyllbot: merge +dev