cdd: Command for Claude Code

Integrate the current state of the base branch into the feature branch. Two phases: a dry-run conflict assessment first, then the actual merge with conflict resolution. The approval between the two phases is conditional — the merge runs automatically when the dry run proves the case mechanically trivial (step 4), and stops for approval otherwise.

Run this command on the feature branch (not on the base branch). Use it when:

• The base branch has advanced under your feature branch and you want to integrate before opening or merging the PR.
• Something useful has landed on the base branch (a new utility, a refactor, an updated convention) that this branch should pick up without a separate roadmap task.

0. Resolve the base branch

BASE_BRANCH=$(cdd-state get base_branch 2>/dev/null)
# With no base recorded, look for a code-host adapter: project, then machine; the first file present wins.
[ -z "$BASE_BRANCH" ] && for c in .cdd/code-host ~/.cdd/adapters/code-host; do [ -e "$c" ] && { CODE_HOST="$c"; break; }; done

If $CODE_HOST is set, check it before using it: the file is executable, and "$CODE_HOST" describe exits 0, parses as JSON, and reports capability code-host and contract 1. If any of that fails, the adapter is installed but broken — say so in one line naming its path, and stop; do not fall back to git, because an installed adapter declares which code host this project uses. If it is usable, say in one line which adapter serves, then take its answer:

BASE_BRANCH=$("$CODE_HOST" default-branch | jq -r '.branch // empty')   # exit 3 (unsupported) or a failure leaves it empty

Whatever is still empty falls back to git, as a bare branch name:

BASE_BRANCH=${BASE_BRANCH:-$(git symbolic-ref --quiet --short refs/remotes/origin/HEAD 2>/dev/null | sed 's#^origin/##')}
BASE_BRANCH=${BASE_BRANCH:-main}

This reads the task's recorded base branch — the branch it was cut from and merges back into. When no base was recorded (every single-integration-branch project), it falls back to the code host's default branch — through the code-host adapter when one is installed, else from git — so behaviour is unchanged there. Use $BASE_BRANCH everywhere main/origin/main appeared in earlier versions of this command. All git commands below use this variable.