Plugin marketplace auto-sync fetches but never pulls, so updates are never applied

Bug Description

The plugin marketplace auto-sync mechanism runs git fetch on marketplace repositories but does not git pull (fast-forward merge) the local branch. This means:

1. lastUpdated timestamp in known_marketplaces.json is refreshed — so it looks like sync ran
2. But the local clone's HEAD stays on the old commit
3. Version comparison sees installed == local (both stale), so no update is triggered
4. New skills, bug fixes, and version bumps in the marketplace are never picked up

Steps to Reproduce

1. Register a custom marketplace: /plugin marketplace add <owner>/<repo>
2. Install a plugin: /plugin install <marketplace-name>
3. Push new commits (including version bumps) to the marketplace repo's main branch
4. Start a new Claude Code session (triggers auto-sync)
5. Observe that the plugin is not updated

Evidence

# After Claude Code auto-sync ran (lastUpdated was refreshed):

$ cd ~/.claude/plugins/marketplaces/de-skills
$ git branch -vv
* main f85ba46 [origin/main: behind 8] feat: remove harness skill from plugin marketplace

# origin/main has the new version, but local HEAD is stale:
$ git log --oneline origin/main -3
9bd4220 chore: bump version to 1.0.2 [skip ci]
a1064ff Merge pull request #12 from khc-dp/test/version
8ba713f test: test version up

Expected Behavior

After git fetch, the local branch should be fast-forwarded to origin/main (or the tracked branch), so that version changes are detected and installed plugins are updated accordingly.

Workaround

Manually pull in the marketplace directory:

cd ~/.claude/plugins/marketplaces/<marketplace-name> && git pull

Then run /skills refresh in the Claude Code session.

Environment

• Claude Code CLI (latest as of 2026-04-01)
• macOS (Darwin 23.4.0)

🤖 Generated with Claude Code