[GH-7682] Add ExpressionDeclaration, AssignmentsProvider, and new call-site API to eliminate raw AST usage in existing lint rules by bkoell · Pull Request #34 · perrystreetsoftware/Rubyzen

Bastian (bkoell) · 2026-06-18T09:07:23Z

What changed and why

Checklist

Tests are added or updated for the changes
YARD docs are added or updated for the changes
bundle exec rake passes locally (runs both the RSpec and Minitest suites)

…l-site API to eliminate raw AST usage in existing lint rules

Copilot

Pull request overview

This PR expands Rubyzen’s AST-wrapping API to reduce (or eliminate) raw RuboCop AST usage in lint rules by introducing first-class “value expression” and “assignment” primitives, plus new call-site convenience APIs. It also updates the sample project with new lint rules demonstrating the new APIs and bumps the gem version to 0.3.0.

Changes:

Add ExpressionDeclaration (+ ExpressionsCollection) to model receivers/arguments/return values with kind predicates (constant/constructor/local var/hash literal/etc.).
Add AssignmentDeclaration (+ AssignmentsProvider/AssignmentsCollection) and ReturnExpressionsProvider with collection bridges on methods/blocks.
Extend CallSiteDeclaration with #arguments, #receiver_expression, and #enclosing_blocks, and add sample lint rules exercising these APIs.

Reviewed changes

Copilot reviewed 30 out of 30 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
spec/declarations/expression_declaration_spec.rb	Adds specs for expression predicates and call-site receiver/argument expression modeling.
spec/declarations/call_site_declaration_spec.rb	Adds specs for `#receiver_expression`, `#arguments`, and `#enclosing_blocks`.
spec/declarations/assignment_declaration_spec.rb	Adds specs for assignment name/value expression behavior (including masgn targets).
spec/collections/expressions_collection_spec.rb	Adds specs for expression collection filters and type-preserving filters.
spec/collections/assignments_collection_spec.rb	Adds specs for assignments collection name filtering and type preservation.
sample_project/src/tests/stubbing_test.rb	Adds sample “violation” source for stubbing Repos constants.
sample_project/src/tests/admin_flow_test.rb	Adds sample “violation” source for admin calls without context wrapper.
sample_project/src/serializers/user_serializer.rb	Adds sample class for “hash literal return” lint rule.
sample_project/src/questions/profile_status.rb	Adds sample class for “no side effects in questions” lint rule.
sample_project/spec/tests/no_stubbing_repos_lint_spec.rb	Adds lint rule using `CallSiteDeclaration#arguments` + `ExpressionDeclaration#constant_name`.
sample_project/spec/tests/admin_calls_use_with_admin_context_lint_spec.rb	Adds lint rule using `CallSiteDeclaration#enclosing_blocks`.
sample_project/spec/spec_helper.rb	Adds `questions` collection helper for question lint rules.
sample_project/spec/questions/no_side_effects_in_questions_lint_spec.rb	Adds lint rule using `#receiver_expression` + method `#assignments` to detect repo writes.
sample_project/spec/core/data_methods_return_data_objects_lint_spec.rb	Adds lint rule using `#return_expressions.hash_literals`.
lib/rubyzen/version.rb	Bumps gem version to 0.3.0.
lib/rubyzen/providers/return_expressions_provider.rb	Introduces provider for method/block return expressions.
lib/rubyzen/providers/enclosing_blocks_provider.rb	Introduces provider for retrieving enclosing blocks for a declaration.
lib/rubyzen/providers/assignments_provider.rb	Introduces provider for collecting local variable assignments.
lib/rubyzen/providers/arguments_provider.rb	Introduces provider for modeling call-site arguments as expressions.
lib/rubyzen/declarations/method_declaration.rb	Mixes in `ReturnExpressionsProvider` and `AssignmentsProvider`.
lib/rubyzen/declarations/expression_declaration.rb	Adds the new expression wrapper declaration and predicates/accessors.
lib/rubyzen/declarations/call_site_declaration.rb	Adds new call-site APIs and includes new providers.
lib/rubyzen/declarations/block_declaration.rb	Mixes in `ReturnExpressionsProvider` and `AssignmentsProvider`.
lib/rubyzen/declarations/assignment_declaration.rb	Adds the new assignment wrapper declaration.
lib/rubyzen/collections/methods_collection.rb	Adds collection bridges for `return_expressions` and `assignments`.
lib/rubyzen/collections/expressions_collection.rb	Adds expression collection filters (`hash_literals`, `constants`).
lib/rubyzen/collections/blocks_collection.rb	Adds collection bridges for `return_expressions` and `assignments`.
lib/rubyzen/collections/assignments_collection.rb	Adds the assignments collection type.
CLAUDE.md	Updates architecture docs with new APIs and data-flow.
CHANGELOG.md	Documents the 0.3.0 additions.

Bastian (bkoell) · 2026-06-23T11:06:30Z

+        nodes = []
+        body = node.body
+        nodes << (body.begin_type? ? body.children.last : body) unless body.nil?
+        node.each_descendant(:return).each do |return_node|
+          nodes << return_node.children.first
+        end


I extracted a ReturnDeclaration (see your other comment below) so value-extraction no longer happens inline in the provider.

Bastian (bkoell) · 2026-06-23T11:06:51Z

+      # Filters to only constant (or constructor-of-constant) expressions.
+      #
+      # @return [ExpressionsCollection]
+      def constants
+        filter(&:constant?)
+      end


Agreed — filters now on constant_name.

Stelios Frantzeskakis (steliosfran) · 2026-06-22T22:34:03Z

+    module ArgumentsProvider
+      # @return [Rubyzen::Collections::ExpressionsCollection]
+      def arguments
+        Collections::ExpressionsCollection.new(


Is it accurate that arguments returns an ExpressionsCollection?

Future-proofing — done. arguments now returns a dedicated ArgumentsCollection. It's a subclass of ExpressionsCollection for now.

Allows for argument-specific filters / behaviour later without a breaking change.

Stelios Frantzeskakis (steliosfran) · 2026-06-22T22:35:37Z

+        nodes = []
+        body = node.body
+        nodes << (body.begin_type? ? body.children.last : body) unless body.nil?
+        node.each_descendant(:return).each do |return_node|
+          nodes << return_node.children.first


I think we shouldn't do the parsing in the provider. Maybe this is a sign that we're missing a ReturnDeclaration and Collection?

Agreed — done.

Stelios Frantzeskakis (steliosfran) · 2026-06-22T22:37:44Z

+    let(:admin_calls) do
+      test_source_files.call_sites
+        .with_name('get')
+        .filter { |cs| cs.source_code.match?(%r{['"]/admin/}) }


Is there any API we can use to avoid the regex?

Stelios Frantzeskakis (steliosfran) · 2026-06-22T22:39:46Z

+    # Violation: a write call via a local variable assigned a Repo
+    # (assignment + local-variable receiver).


I'm not sure if we want these Violation / Compliant comments since they're specific to one lint rule, while multiple lint rules will lint this file.

Same for the two other files below.

Stelios Frantzeskakis (steliosfran) · 2026-06-22T22:42:11Z

+- **`ExpressionDeclaration`** — a value-expression primitive wrapping any AST node, with
+  predicates (`constant?`, `local_variable?`, `method_call?`, `constructor?`, `hash_literal?`,
+  `symbol?`, `string?`) and accessors (`constant_name`, `method_name`, `name`). Surfaced through
+  new providers so rules can inspect values without dropping to the raw AST.


I would remove this line ("Surfaced through new providers so rules .."). It looks very AI-generated and it's also apparent that we're building new APIs to avoid raw AST access.

Stelios Frantzeskakis (steliosfran) · 2026-06-22T22:45:10Z

+  module Providers
+    # Provides the chain of blocks (do..end / { }) that lexically enclose a declaration,
+    # innermost first.
+    module EnclosingBlocksProvider


Is the naming accurate considering we have a similar one? (BlocksProvider)?

I think the names are accurate and complementary: BlocksProvider returns the blocks contained within a node, whereas EnclosingBlocksProvider returns the blocks that wrap it. Kept as-is, but happy to revisit if you'd prefer something else.

- Extract ReturnDeclaration + ReturnsCollection + ReturnsProvider; #returns is now the primary API and #return_expressions a shortcut for returns.expressions. Fixes two correctness bugs in the old provider: explicit begin..end (kwbegin) bodies now surface their final expression, and the `return` node itself no longer leaks into the expression collection. - ExpressionsCollection#constants now filters on constant_name, so it includes constructor-of-constant expressions (e.g. Repos::Foo.new) per its documented contract. - Introduce ArgumentsCollection (a subclass of ExpressionsCollection) as the return type of CallSiteDeclaration#arguments, so argument-specific filters can be added later without a breaking change. - Admin lint rule uses CallSiteDeclaration#strings instead of a source_code regex. - Remove rule-specific Violation/Compliant comments from sample source files. - CHANGELOG: drop AI-sounding line; document the returns API. CLAUDE.md updated.

[GH-7682] Add ExpressionDeclaration, AssignmentsProvider, and new cal…

20b3f0e

…l-site API to eliminate raw AST usage in existing lint rules

Copilot AI review requested due to automatic review settings June 18, 2026 09:07

Copilot started reviewing on behalf of Bastian (bkoell) June 18, 2026 09:07 View session

Bastian (bkoell) requested a review from Stelios Frantzeskakis (steliosfran) June 18, 2026 09:08

Copilot AI reviewed Jun 18, 2026

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Stelios Frantzeskakis (steliosfran) reviewed Jun 22, 2026

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Bastian (bkoell) requested a review from Stelios Frantzeskakis (steliosfran) June 23, 2026 11:12

		# Violation: a write call via a local variable assigned a Repo
		# (assignment + local-variable receiver).

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Bastian (bkoell) commented Jun 18, 2026

What changed and why

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Stelios Frantzeskakis (steliosfran) Jun 22, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Stelios Frantzeskakis (steliosfran) Jun 22, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Stelios Frantzeskakis (steliosfran) Jun 22, 2026 •

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Stelios Frantzeskakis (steliosfran) Jun 22, 2026 •

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