feat: add AI branch and commit generation to create command

[dubscode]

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🥞 DubStack

• feat: add AI branch and commit generation to create command #15 feat: add AI branch and commit generation to create command 👈

[Copilot]

Pull request overview

Adds an AI-assisted mode to dub create so users can generate a stacked branch name and Conventional Commit message from staged changes, while also tightening branch-name validation.

Changes:

• Add --ai/-i mode to dub create, making the branch argument optional and generating branch+commit metadata from the staged diff.
• Introduce isValidBranchName() (git ref-format validation) and apply it during create.
• Update tests and docs (README/Quickstart) to cover the new --ai workflow and option-combo rules.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/lib/git.ts	Adds isValidBranchName() helper using git check-ref-format.
src/lib/git.test.ts	Adds unit tests for isValidBranchName().
src/index.ts	Updates create CLI: optional branch arg + new --ai option + revised help text.
src/commands/create.ts	Implements AI branch/commit generation from staged diff; validates generated/manual branch names.
src/commands/create.test.ts	Adds coverage for create --ai behavior and config gating.
README.md	Updates dub create docs and examples for optional branch + --ai.
QUICKSTART.md	Adds --ai examples to the quickstart flow.

Comments suppressed due to low confidence (3)

src/commands/create.ts:61

• The JSDoc for create() still describes name as a required branch name, but the function now accepts string | undefined (to support --ai). Update the @param name description to reflect that it may be omitted when --ai is used (and required otherwise), so the docs match runtime behavior.

 * @param name - Name of the new branch to create
 * @param cwd - Working directory (auto-initializes if needed)
 * @param options - Optional create flags
 * @returns The created branch name, its parent, and committed message if applicable
 * @throws {DubError} If branch exists, HEAD is detached, invalid option combos, or nothing to commit

src/commands/create.test.ts:205

• The create() signature now accepts name: string | undefined, so this test no longer needs to force undefined through as unknown as string. Passing undefined directly keeps the test type-safe and avoids masking real typing issues.

    const result = await create(
      undefined as unknown as string,
      dir,
      { ai: true },
      {
        generateText,
        createGoogleGenerativeAI,

src/commands/create.ts:244

• resolveModel() duplicates the provider-selection logic (env var precedence + model IDs + error message) that already exists in src/commands/ai.ts. Consider extracting a shared helper (e.g. src/lib/ai-model.ts) and reusing it here to avoid the two implementations drifting (different model IDs, env vars, or error text).

function resolveModel(deps: CreateDependencies): {
  provider: 'google' | 'gateway';
  model: LanguageModel;
  modelId: string;
} {
  const geminiApiKey = process.env.DUBSTACK_GEMINI_API_KEY?.trim();
  if (geminiApiKey) {
    const google = deps.createGoogleGenerativeAI({ apiKey: geminiApiKey });
    return {
      provider: 'google',
      model: google('gemini-3-flash'),
      modelId: 'gemini-3-flash',
    };
  }

  const gatewayApiKey = process.env.DUBSTACK_AI_GATEWAY_API_KEY?.trim();
  if (gatewayApiKey) {
    const gateway = deps.createGateway({ apiKey: gatewayApiKey });
    return {
      provider: 'gateway',
      model: gateway('google/gemini-3-flash'),
      modelId: 'google/gemini-3-flash',
    };
  }

  throw new DubError(
    "AI assistant requires DUBSTACK_GEMINI_API_KEY or DUBSTACK_AI_GATEWAY_API_KEY. Run 'dub ai env --gemini-key <key>' or 'dub ai env --gateway-key <key>'.",
  );
}

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