From 73735b503cba36fb8bde717d57a1f901f574eb8f Mon Sep 17 00:00:00 2001
From: Hiroshi SHIBATA <hsbt@ruby-lang.org>
Date: Tue, 3 Feb 2026 21:03:25 +0900
Subject: [PATCH 1/3] Added failing example

---
 bundler/spec/install/gemfile/sources_spec.rb | 37 ++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/bundler/spec/install/gemfile/sources_spec.rb b/bundler/spec/install/gemfile/sources_spec.rb
index 69b0816a1899..4957ef70be2c 100644
--- a/bundler/spec/install/gemfile/sources_spec.rb
+++ b/bundler/spec/install/gemfile/sources_spec.rb
@@ -1236,4 +1236,41 @@
       expect(the_bundle).to include_gems("fallback_dep 1.0.0", source: "remote2")
     end
   end
+
+  context "when a path gem has a transitive dependency that does not exist in the path source" do
+    before do
+      build_repo2 do
+        build_gem "missing_dep", "1.0.0"
+        build_gem "foo", "1.0.0"
+      end
+
+      build_lib "parent_gem", "1.0.0", path: lib_path("parent_gem") do |s|
+        s.add_dependency "missing_dep"
+      end
+
+      gemfile <<-G
+        source "https://gem.repo2"
+
+        gem "foo"
+
+        gem "parent_gem", path: "#{lib_path("parent_gem")}"
+      G
+
+      bundle :install, artifice: "compact_index"
+    end
+
+    it "falls back to the default rubygems source for that dependency when updating" do
+      build_repo2 do
+        build_gem "foo", "2.0.0"
+      end
+
+      system_gems []
+
+      bundle "update foo", artifice: "compact_index"
+
+      expect(the_bundle).to include_gems("parent_gem 1.0.0", "missing_dep 1.0.0", "foo 2.0.0")
+      expect(the_bundle).to include_gems("parent_gem 1.0.0", source: "path@#{lib_path("parent_gem")}")
+      expect(the_bundle).to include_gems("missing_dep 1.0.0", source: "remote2")
+    end
+  end
 end

From 7c89d2588d66bd1998804055614138826ad89b31 Mon Sep 17 00:00:00 2001
From: Hiroshi SHIBATA <hsbt@ruby-lang.org>
Date: Wed, 4 Feb 2026 10:51:06 +0900
Subject: [PATCH 2/3] Require parent path source to contain matching specs
 before selecting it as replacement

---
 bundler/lib/bundler/definition.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/bundler/lib/bundler/definition.rb b/bundler/lib/bundler/definition.rb
index 639740e46b6b..3cf9fbe8bf03 100644
--- a/bundler/lib/bundler/definition.rb
+++ b/bundler/lib/bundler/definition.rb
@@ -1077,7 +1077,7 @@ def converge_specs(specs)
             end
           end
 
-          if parent_dep && parent_dep.source.is_a?(Source::Path)
+          if parent_dep && parent_dep.source.is_a?(Source::Path) && parent_dep.source.specs[s]&.any?
             replacement_source = parent_dep.source
           else
             replacement_source = sources.get(lockfile_source)

From 00c8bb7bc5536a2858933c7436a71bc93a76068a Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 4 Feb 2026 02:50:52 +0000
Subject: [PATCH 3/3] Add test case for git sources with transitive
 dependencies

Co-authored-by: hsbt <12301+hsbt@users.noreply.github.com>
---
 bundler/spec/install/gemfile/sources_spec.rb | 37 ++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/bundler/spec/install/gemfile/sources_spec.rb b/bundler/spec/install/gemfile/sources_spec.rb
index 4957ef70be2c..c72a2b982a99 100644
--- a/bundler/spec/install/gemfile/sources_spec.rb
+++ b/bundler/spec/install/gemfile/sources_spec.rb
@@ -1273,4 +1273,41 @@
       expect(the_bundle).to include_gems("missing_dep 1.0.0", source: "remote2")
     end
   end
+
+  context "when a git gem has a transitive dependency that does not exist in the git source" do
+    before do
+      build_repo2 do
+        build_gem "missing_dep", "1.0.0"
+        build_gem "foo", "1.0.0"
+      end
+
+      build_git "parent_gem", "1.0.0", path: lib_path("parent_gem") do |s|
+        s.add_dependency "missing_dep"
+      end
+
+      gemfile <<-G
+        source "https://gem.repo2"
+
+        gem "foo"
+
+        gem "parent_gem", git: "#{lib_path("parent_gem")}"
+      G
+
+      bundle :install, artifice: "compact_index"
+    end
+
+    it "falls back to the default rubygems source for that dependency when updating" do
+      build_repo2 do
+        build_gem "foo", "2.0.0"
+      end
+
+      system_gems []
+
+      bundle "update foo", artifice: "compact_index"
+
+      expect(the_bundle).to include_gems("parent_gem 1.0.0", "missing_dep 1.0.0", "foo 2.0.0")
+      expect(the_bundle).to include_gems("parent_gem 1.0.0", source: "git@#{lib_path("parent_gem")}")
+      expect(the_bundle).to include_gems("missing_dep 1.0.0", source: "remote2")
+    end
+  end
 end