Skip RBS rewriter when file does not contain RBS syntax by dejmedus · Pull Request #917 · Shopify/spoom

dejmedus · 2026-05-12T19:39:33Z

closes Skip RBS rewriter when a file doesn't contain any RBS syntax #916
moved from tapioca Skip RBS rewrite when no markers are present tapioca#2616

If a file does not contain typed file markers (ex # typed: true) or RBS syntax we can skip attempting to translate it. If a file has not been rewritten we can exclude it from the count of translated files

amomchilov · 2026-05-12T20:17:48Z

          RB
        end

+        def test_should_rewrite_returns_true_for_supported_typed_sigils


Two more cases to test:

Don't trigger if # typed: true exists later in the file. This is unlikely, but it's a performance improvement to ensure we're not scanning through the whole file

Trigger if there's multiple magic comments, but typed isn't first:

# frozen_string_literal: true # typed: true

Don't trigger if # typed: true exists later in the file

Good call! I updated to only check for the typed marker in the magic comments block

dejmedus · 2026-05-12T21:33:50Z

+              next if new_contents == contents
+
+              File.write(file, new_contents)
              transformed_count += 1


This will only count changed files in the Translated signatures in <x> files. message, but I'm happy to drop the commit if we want to leave as is

When a file is not typed or contains no RBS comment syntax, we can skip running the RBS rewriter on it Co-authored-by: Matt Kubej <matt.kubej@shopify.com>

dejmedus · 2026-05-12T22:27:05Z

      class RBSCommentsToSorbetSigs < Translator
        include Spoom::RBS::ExtractRBSComments

+        magic_comments = /\A(?:\s*#[^\n]*\n)*/


Grabs the magic comments block, considered here as everything up until the first non-comment, non-empty line

paracycle

Shouldn't all this logic be encapsulated inside the RBSCommentsToSorbetSigs class, which already stores the ruby_contents as an ivar, and wouldn't need to pass it to a should_rewrite? method. The downside is just an extra object allocation only to return the same contents, but I think that's fine.

amomchilov · 2026-05-12T23:01:47Z

+          #: (String source) -> bool
+          def should_rewrite?(source)
+            source.match?(TYPED_FILE_PATTERN) && source.match?(RBS_REWRITE_PATTERN)
+          end


To what Ufuk was saying, maybe we can add a rewrite class method:

Suggested change

end

end

#: (String ruby_contents, file: String, ?max_line_length: Integer?) -> String

def rewrite(ruby_contents, file:, max_line_length: nil)

# fast path, skip parsing/visiting if there's no RBS syntax at all

return ruby_contents if should_rewrite?(ruby_contents)

new(ruby_contents, file:, max_line_length:).rewrite

end

amomchilov

Few small points, but it's shaping up!

amomchilov · 2026-05-12T23:02:29Z

+          "# @overridable",
+          "# @without_runtime",
+        ].freeze #: Array[String]
+        RBS_REWRITE_PATTERN = Regexp.union(["#:", "#|"] + RBS_ANNOTATION_MARKERS).freeze #: Regexp


tiny opt:

Suggested change

RBS_REWRITE_PATTERN = Regexp.union(["#:", "#|"] + RBS_ANNOTATION_MARKERS).freeze #: Regexp

RBS_REWRITE_PATTERN = Regexp.union(["#:", "#|", *RBS_ANNOTATION_MARKERS]).freeze #: Regexp

Spares one allocation :)

require "bundler/inline" gemfile do source "https://rubygems.org" gem "benchmark-memory" end a = [3, 4, 5] Benchmark.memory do |x| x.report(" +") { [1, 2] + a } x.report("splat") { [1, 2, *a] } x.compare! end # Calculating ------------- # + 120.000 memsize # 2.000 objects # splat 208.000 memsize # 1.000 objects

amomchilov · 2026-05-12T23:04:53Z

+
+        class << self
+          #: (String source) -> bool
+          def should_rewrite?(source)


if this is going to be public API, perhaps contains_rbs_syntax? would be more clear to callers

amomchilov · 2026-05-12T23:12:43Z

+          end
+        end
+
+        def test_calls_new_for_files_with_rbs_syntax


eh, I don't think this is a useful test. it's implied from the other more end-to-endy tests.

amomchilov · 2026-05-12T23:14:07Z

+                #{marker}
+                class Foo; end
+              RB
+              marker,


Suggested change

marker,

"#should_rewrite? should return true for files containing #{marker}",

amomchilov · 2026-05-12T23:14:36Z

+            "# @sealed",
+            "# @final",
+            "# @requires_ancestor:",
+            "# @override",


I think you can just move these here and remove the next test

Suggested change

"# @override",

"# @override",

"# @override(allow_incompatible: true)",

"# @override(allow_incompatible: false)",

"# @override(allow_incompatible: :visibility)",

amomchilov · 2026-05-12T23:15:59Z

+          end
+        end
+
+        def test_should_rewrite_returns_false_for_files_without_rbs_syntax


Can you please reorder these, so related tests are better grouped together?

E.g. the def test_should_rewrite_returns_false_when_the_file_is_not_typed should be in this area, where the other test_should_rewrite_returns_false_for_ tests are

amomchilov · 2026-05-12T23:17:27Z

+  end
 end

+Spoom::Sorbet::Translate::RBSCommentsToSorbetSigs::RBS_ANNOTATION_MARKERS = T.let(T.unsafe(nil), Array)


Let's mark these with private_constant where they're defined, so we don't expose them to the public.

dejmedus force-pushed the jb-rbs-marker-gaurd branch from 82e90b7 to 07a9394 Compare May 12, 2026 19:51

amomchilov reviewed May 12, 2026

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dejmedus force-pushed the jb-rbs-marker-gaurd branch from 07a9394 to 47118ab Compare May 12, 2026 20:57

github-advanced-security AI found potential problems May 12, 2026

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Comment thread lib/spoom/sorbet/translate/rbs_comments_to_sorbet_sigs.rb Fixed

Comment thread lib/spoom/sorbet/translate/rbs_comments_to_sorbet_sigs.rb Fixed

dejmedus force-pushed the jb-rbs-marker-gaurd branch 2 times, most recently from cf00c3f to d3125ac Compare May 12, 2026 21:23

dejmedus commented May 12, 2026

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dejmedus and others added 3 commits May 12, 2026 16:24

Skip RBS rewrite when file contains no RBS syntax

5b9b7b7

When a file is not typed or contains no RBS comment syntax, we can skip running the RBS rewriter on it Co-authored-by: Matt Kubej <matt.kubej@shopify.com>

Add typed: true to test example files

7bf79eb

Don't count unchanged files in translated file number

f25aa67

dejmedus force-pushed the jb-rbs-marker-gaurd branch from d3125ac to f25aa67 Compare May 12, 2026 22:26

dejmedus commented May 12, 2026

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dejmedus marked this pull request as ready for review May 12, 2026 22:46

dejmedus requested a review from a team as a code owner May 12, 2026 22:46

dejmedus requested a review from amomchilov May 12, 2026 22:47

paracycle reviewed May 12, 2026

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amomchilov reviewed May 12, 2026

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-          end
+          end
+          #: (String ruby_contents, file: String, ?max_line_length: Integer?) -> String
+          def rewrite(ruby_contents, file:, max_line_length: nil)
+            # fast path, skip parsing/visiting if there's no RBS syntax at all
+            return ruby_contents if should_rewrite?(ruby_contents)
+            new(ruby_contents, file:, max_line_length:).rewrite
+          end

	RBS_REWRITE_PATTERN = Regexp.union(["#:", "#\|"] + RBS_ANNOTATION_MARKERS).freeze #: Regexp
	RBS_REWRITE_PATTERN = Regexp.union(["#:", "#\|", *RBS_ANNOTATION_MARKERS]).freeze #: Regexp

	marker,
	"#should_rewrite? should return true for files containing #{marker}",

-            "# @override",
+            "# @override",
+            "# @override(allow_incompatible: true)",
+            "# @override(allow_incompatible: false)",
+            "# @override(allow_incompatible: :visibility)",

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dejmedus commented May 12, 2026 •

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