[ruby/rubygems] Validate override version requirement at Gemfile evaluation time

Before this change, `override "rails", version: "not a version"` was
accepted by Bundler::Dsl#override and only failed later when the
resolver tried to instantiate Gem::Requirement. Surface the error at
the Gemfile evaluation step so the user sees it on the offending line.

https://github.com/ruby/rubygems/commit/2ae83fbb4f

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

2 files changed, 18 insertions, 1 deletions

diff --git a/lib/bundler/dsl.rb b/lib/bundler/dsl.rb
index c7a7d855ee..05eb493677 100644
--- a/lib/bundler/dsl.rb
+++ b/lib/bundler/dsl.rb
@@ -279,7 +279,9 @@ module Bundler
 
     def validate_override_operation!(operation)
       case operation
-      when String, nil
+      when String
+        Gem::Requirement.new(operation)
+      when nil
         # ok
       when Symbol
         return if SUPPORTED_OVERRIDE_SYMBOL_OPERATIONS.include?(operation)
@@ -287,6 +289,8 @@ module Bundler
       else
         raise ArgumentError, "override operation must be a String, Symbol, or nil, got #{operation.inspect}"
       end
+    rescue Gem::Requirement::BadRequirementError => e
+      raise ArgumentError, "invalid override version requirement #{operation.inspect}: #{e.message}"
     end
 
     def validate_override_uniqueness!(target, field)
diff --git a/spec/bundler/bundler/dsl_spec.rb b/spec/bundler/bundler/dsl_spec.rb
index 39f745c05e..99ab9088f9 100644
--- a/spec/bundler/bundler/dsl_spec.rb
+++ b/spec/bundler/bundler/dsl_spec.rb
@@ -441,6 +441,19 @@ RSpec.describe Bundler::Dsl do
       end.to raise_error(ArgumentError, /unsupported override operation/)
     end
 
+    it "raises ArgumentError for an unparsable version string" do
+      expect do
+        subject.override("rails", version: "not a version")
+      end.to raise_error(ArgumentError, /invalid override version requirement/)
+    end
+
+    it "does not record an override when the version string is invalid" do
+      expect do
+        subject.override("rails", version: "not a version")
+      end.to raise_error(ArgumentError)
+      expect(subject.overrides).to eq([])
+    end
+
     it "rejects atomically when one field in a multi-field call is invalid" do
       expect do
         subject.override("rails", version: ">= 8.0", required_ruby_version: :ignore_upper)