Apply override version operations in Resolver

Pass the Definition's overrides through to Resolver::Base and rewrite
each dependency's requirement at the entry of to_dependency_hash so
both direct and transitive deps are reshaped before PubGrub sees them.
The hook is the same point Shopify/bundler-ignore-dependency uses,
since prepare_dependencies and the @cached_dependencies closure both
funnel through to_dependency_hash. Override#apply_to handles all
three operation kinds, so :ignore_upper and nil also start working
from this commit; integration coverage for those paths follows in
later commits.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hsbt

bundler/lib/bundler/definition.rb

@@ -1275,7 +1275,7 @@ def unlocked_resolution_base
 
     def new_resolution_base(last_resolve:, unlock:)
       new_resolution_platforms = @current_platform_missing ? @new_platforms + [Bundler.local_platform] : @new_platforms
-      Resolver::Base.new(source_requirements, expanded_dependencies, last_resolve, @platforms, locked_specs: @originally_locked_specs, unlock: unlock, prerelease: gem_version_promoter.pre?, prefer_local: @prefer_local, new_platforms: new_resolution_platforms)
+      Resolver::Base.new(source_requirements, expanded_dependencies, last_resolve, @platforms, locked_specs: @originally_locked_specs, unlock: unlock, prerelease: gem_version_promoter.pre?, prefer_local: @prefer_local, new_platforms: new_resolution_platforms, overrides: @overrides)
     end
 
     def new_resolver(base)

bundler/lib/bundler/resolver.rb

@@ -510,7 +510,7 @@ def requirement_to_range(requirement)
     end
 
     def to_dependency_hash(dependencies, packages)
-      dependencies.inject({}) do |deps, dep|
+      apply_overrides(dependencies).inject({}) do |deps, dep|
         package = packages[dep.name]
 
         current_req = deps[package]
@@ -526,6 +526,16 @@ def to_dependency_hash(dependencies, packages)
       end
     end
 
+    def apply_overrides(dependencies)
+      return dependencies if @base.overrides.empty?
+
+      dependencies.map do |dep|
+        override = @base.overrides.find {|o| o.target == dep.name && o.field == :version }
+        next dep unless override
+        Gem::Dependency.new(dep.name, override.apply_to(dep.requirement))
+      end
+    end
+
     def bundler_not_found_message(conflict_dependencies)
       candidate_specs = filter_matching_specs(default_bundler_source.specs.search("bundler"), conflict_dependencies)
 

bundler/lib/bundler/resolver/base.rb

@@ -5,9 +5,10 @@
 module Bundler
   class Resolver
     class Base
-      attr_reader :packages, :requirements, :source_requirements, :locked_specs
+      attr_reader :packages, :requirements, :source_requirements, :locked_specs, :overrides
 
       def initialize(source_requirements, dependencies, base, platforms, options)
+        @overrides = options.delete(:overrides) || []
         @source_requirements = source_requirements
         @locked_specs = options[:locked_specs]
 

spec/install/gemfile/override_spec.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+RSpec.describe "override DSL" do
+  context "with a version: string operation" do
+    it "replaces a direct dependency requirement with the override version spec" do
+      install_gemfile <<-G
+        source "https://gem.repo1"
+        override "myrack", version: "= 0.9.1"
+        gem "myrack"
+      G
+
+      expect(the_bundle).to include_gems "myrack 0.9.1"
+    end
+
+    it "replaces a transitive dependency requirement" do
+      install_gemfile <<-G
+        source "https://gem.repo1"
+        override "myrack", version: "= 1.0.0"
+        gem "myrack_middleware"
+      G
+
+      expect(the_bundle).to include_gems "myrack 1.0.0", "myrack_middleware 1.0"
+    end
+
+    it "replaces the requirement even when the Gemfile pins a different version" do
+      install_gemfile <<-G
+        source "https://gem.repo1"
+        override "myrack", version: "= 0.9.1"
+        gem "myrack", "= 1.0.0"
+      G
+
+      expect(the_bundle).to include_gems "myrack 0.9.1"
+    end
+  end
+end

spec/support/windows_tag_group.rb

@@ -190,6 +190,7 @@ module WindowsTagGroup
         "spec/install/gems/no_build_extension_spec.rb",
         "spec/install/gems/no_install_plugin_spec.rb",
         "spec/bundler/override_spec.rb",
+        "spec/install/gemfile/override_spec.rb",
       ],
     }.freeze
   end