Stash frequently used Drop setter keys for reuse

[ashmaroli]

• This is an ⚡ optimization change.

Summary

Jekyll::Render is initialized for every page or document rendered in a site and invariably calls Jekyll::Drops::Drop#[]= with a series of keys via its #run method:

jekyll/lib/jekyll/renderer.rb

Lines 52 to 58 in 7e0f907

	def run
	Jekyll.logger.debug "Rendering:", document.relative_path
	assign_pages!
	assign_current_document!
	assign_highlighter_options!
	assign_layout_data!

---

jekyll/lib/jekyll/renderer.rb

Lines 214 to 217 in 7e0f907

	def assign_pages!
	payload["page"] = document.to_liquid
	payload["paginator"] = (document.pager.to_liquid if document.respond_to?(:pager))
	end

jekyll/lib/jekyll/renderer.rb

Lines 229 to 232 in 7e0f907

	def assign_highlighter_options!
	payload["highlighter_prefix"] = converters.first.highlighter_prefix
	payload["highlighter_suffix"] = converters.first.highlighter_suffix
	end

jekyll/lib/jekyll/renderer.rb

Lines 234 to 237 in 7e0f907

	def assign_layout_data!
	layout = layouts[document.data["layout"]]
	payload["layout"] = Utils.deep_merge_hashes(layout.data, payload["layout"] || {}) if layout
	end

jekyll/lib/jekyll/renderer.rb

Lines 190 to 192 in 7e0f907

	def render_layout(output, layout, info)
	payload["content"] = output
	payload["layout"] = Utils.deep_merge_hashes(layout.data, payload["layout"] || {})

---

The constant is currently private so that it can be replaced with a class-scoped cache in a future version if needed.

[ashmaroli]

Third Party Repo Profile Summary

--- master
+++ PR

- Total allocated: 282.43 MB (2467827 objects)
+ Total allocated: 280.79 MB (2426843 objects)
  Total retained:  37.81 MB (112069 objects)

[DirtyF]

No gain on the build time?

[ashmaroli]

No gain on the build time?

No. Because we're replacing String interpolation with a Hash lookup.
At interpreter level, they're comparably performant.

The notable gain here is reduced allocations in a large site with numerous pages and documents especially because Jekyll::Renderer#run will inevitably run for all of them..

[DirtyF]

What is a large site? I thought the one was big enough to reflect gain.

[ashmaroli]

What is a large site?

A site with numerous pages and documents (and excerpts)

I thought the one was big enough to reflect gain.

Yes. The third-party site is large enough.
But the proposed change in the PR does not result in greater performance.
Just reduced allocations and therefore reduced strain on Ruby's Garbage Collector.

[ashmaroli]

@jekyllbot: merge +fix