feat(cli): add gem-contribute open <gem>

lib/gem_contribute/cli.rb

@@ -23,6 +23,8 @@ module CLI
                                  GitHub project (e.g. `rubyevents/rubyevents`).
                                  Lands on the default branch.
                                  Flags: -e (editor), -a (AI tool).
+        open <gem>               Open the gem's GitHub repo in your default browser.
+                                 The URL is also printed on stdout as a fallback.
         fix <gem>/<issue#>       Fork the gem's repo, clone the fork, branch from main.
                                  Flags: -e (editor), -a (AI tool), --no-comment.
         submit                   Push the current branch and open a pre-filled
@@ -63,6 +65,7 @@ def dispatch(command, argv, stdout:, stderr:)
       "config" => ->(o, e) { Config.new(stdout: o, stderr: e) },
       "auth" => ->(o, e) { Auth.new(stdout: o, stderr: e) },
       "fork" => ->(o, e) { Fork.new(stdout: o, stderr: e, clone_root: GemContribute::Config.new.clone_root) },
+      "open" => ->(o, e) { Open.new(stdout: o, stderr: e) },
       "fix" => lambda { |o, e|
         config = GemContribute::Config.new
         Fix.new(stdout: o, stderr: e, clone_root: config.clone_root, config: config)

lib/gem_contribute/cli/open.rb

@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+module GemContribute
+  module CLI
+    # `gem-contribute open <gem>` — print the gem's GitHub URL and try to open
+    # it in the default browser.
+    #
+    # Resolves `<gem>` the same way `issues` and `fix` do (RubyGems → Project,
+    # with the `gem-contribute` self short-circuit). The browser opener is the
+    # same platform-aware helper used by `auth login` and `submit`. As in those
+    # verbs, the opener is injected at construction so specs never shell out.
+    class Open
+      include PlatformTools
+      include Workflow
+
+      USAGE = "Usage: gem-contribute open <gem>"
+
+      def initialize(stdout: $stdout, stderr: $stderr, output: nil,
+                     resolver: Resolver.new,
+                     browser_opener: nil)
+        @output = output || Output::Standard.new(out: stdout, err: stderr)
+        @resolver = resolver
+        @browser_opener = browser_opener || method(:default_browser_opener)
+      end
+
+      def run(argv)
+        target = argv.shift
+        if target.nil?
+          @output.error(USAGE)
+          return 2
+        end
+
+        project = resolve_target(target, verb: "open")
+        return 1 if project.nil?
+
+        url = "https://github.com/#{project.owner}/#{project.repo}"
+        opened = @browser_opener.call(url)
+        @output.info(opened ? "Opened browser to:" : "Open this URL in your browser:")
+        @output.info("  #{url}")
+        0
+      end
+    end
+  end
+end

spec/gem_contribute/cli/open_spec.rb

@@ -0,0 +1,76 @@
+# frozen_string_literal: true
+
+require "stringio"
+
+RSpec.describe GemContribute::CLI::Open do
+  let(:stdout) { StringIO.new }
+  let(:stderr) { StringIO.new }
+  let(:resolver) { instance_double(GemContribute::Resolver) }
+  let(:opened_urls) { [] }
+  let(:browser_opener) do
+    lambda do |url|
+      opened_urls << url
+      true
+    end
+  end
+  let(:cli) do
+    described_class.new(stdout: stdout, stderr: stderr,
+                        resolver: resolver, browser_opener: browser_opener)
+  end
+
+  let(:project) do
+    GemContribute::Project.new(
+      gem_name: "rubocop", host: "github.com",
+      owner: "rubocop", repo: "rubocop", metadata: {}
+    )
+  end
+
+  it "exits 2 with a usage message when no gem name is given" do
+    expect(cli.run([])).to eq(2)
+    expect(stderr.string).to include("Usage: gem-contribute open <gem>")
+  end
+
+  it "opens the resolved repo URL in the browser and prints it" do
+    allow(resolver).to receive(:resolve).and_return(project)
+
+    expect(cli.run(["rubocop"])).to eq(0)
+    expect(opened_urls).to eq(["https://github.com/rubocop/rubocop"])
+    out = stdout.string
+    expect(out).to include("Opened browser to:")
+    expect(out).to include("https://github.com/rubocop/rubocop")
+  end
+
+  it "still prints the URL when the browser opener returns false" do
+    allow(resolver).to receive(:resolve).and_return(project)
+    failing_opener = ->(_url) { false }
+    cli = described_class.new(stdout: stdout, stderr: stderr,
+                              resolver: resolver, browser_opener: failing_opener)
+
+    expect(cli.run(["rubocop"])).to eq(0)
+    out = stdout.string
+    expect(out).to include("Open this URL in your browser:")
+    expect(out).to include("https://github.com/rubocop/rubocop")
+  end
+
+  it "exits 1 with a clear message when the gem resolves to a non-github.com host" do
+    other = GemContribute::Project.new(
+      gem_name: "internal", host: :unknown, owner: nil, repo: nil, metadata: {}
+    )
+    allow(resolver).to receive(:resolve).and_return(other)
+
+    expect(cli.run(["internal"])).to eq(1)
+    expect(stderr.string).to include("only github.com is supported")
+    expect(opened_urls).to be_empty
+  end
+
+  it "self-resolves `gem-contribute` without hitting the resolver" do
+    allow(resolver).to receive(:resolve)
+
+    expect(cli.run(["gem-contribute"])).to eq(0)
+    expect(resolver).not_to have_received(:resolve)
+    expect(opened_urls).to eq([
+                                "https://github.com/#{GemContribute::SELF_PROJECT.owner}/" \
+                                "#{GemContribute::SELF_PROJECT.repo}"
+                              ])
+  end
+end