Fix Gemspecs#in_this_bundle? crash when no Gemfile is discoverable

Bundler.definition raises Bundler::GemfileNotFound (not nil) when no
Gemfile is discoverable from the current process's working directory
- e.g. when Solargraph is installed and invoked as a standalone gem.
The safe-navigation chain in in_this_bundle? doesn't help since the
exception happens while evaluating Bundler.definition itself, which
crashed find_gem and, downstream, the CLI's unbundled-environment
paths exercised by this PR's shell.rb wiring.

Same fix as castwide#1225 (open upstream, not yet merged);
included directly here so this PR's own CI is green without waiting
on that PR to land first. Once castwide#1225 merges, a future rebase of this
branch will see it as a no-op.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: apiology

lib/solargraph/workspace/gemspecs.rb

@@ -220,6 +220,12 @@ def query_external_bundle command
       # @sg-ignore need boolish support for ? methods
       def in_this_bundle?
         Bundler.definition&.lockfile&.to_s&.start_with?(directory)
+      rescue Bundler::GemfileNotFound
+        # Solargraph itself isn't running under a discoverable Gemfile
+        # (e.g. installed and invoked as a standalone gem), so it can't
+        # be "this bundle" - fall back to treating the workspace as an
+        # external bundle.
+        false
       end
 
       # @return [Array<Gem::Specification, Bundler::LazySpecification, Bundler::StubSpecification>]

spec/workspace/gemspecs_find_gem_spec.rb

@@ -97,4 +97,23 @@
       end
     end
   end
+
+  context 'when Solargraph itself is not running under a discoverable Gemfile' do
+    # Regression test: Bundler.definition raises Bundler::GemfileNotFound
+    # (rather than returning nil) when no Gemfile is discoverable from the
+    # current process, e.g. when Solargraph is installed and invoked as a
+    # standalone gem. #in_this_bundle? must not let that exception escape.
+    let(:dir_path) { File.realpath(Dir.mktmpdir) }
+    let(:name) { 'solargraph' }
+    let(:version) { nil }
+
+    before do
+      allow(Bundler).to receive(:definition).and_raise(Bundler::GemfileNotFound, 'Could not locate Gemfile')
+    end
+
+    it 'falls back to resolving gems ignoring any local bundle instead of raising' do
+      expect { gemspec }.not_to raise_error
+      expect(gemspec.name).to eq(name)
+    end
+  end
 end