Monorepo: feature branches share the root repo's branch namespace (no per-project Git scoping)

[PascalThuet]

Correction (updated): the original premise — that branch creation is skipped — was wrong. Verified end-to-end on main (487af97): in a normally-installed project the branch is created in the shared root repo. This issue has been re-scoped to the actual residual; see the correction comment below.

Summary

In a monorepo with one Git repository at the root and Spec Kit projects in subdirectories (e.g. apps/web/.specify/), feature-branch creation works — the branch is created/switched in the shared root repository. The residual is that all member projects share that single branch namespace, while feature numbering is per-project, so feature numbers are not unique across the monorepo and branches from different member projects interleave in one namespace.

Why

create-new-feature-branch.sh resolves REPO_ROOT to the member project (the directory containing .specify/) and, in a normal install, detects Git via git -C "$REPO_ROOT" rev-parse --is-inside-work-tree (core common.sh does not define has_git). That walks up to the enclosing work tree, so the branch lands in the root repo. Feature numbering comes from the member project's own specs/.

Impact

• Two member projects can each produce a 001-… branch in the same repo; numbers carry no monorepo-wide meaning.
• There is no way to scope branches per member project short of initializing a separate Git repo per project.

Possible direction

Per-project / custom branch namespacing for monorepos. Closely related to #1382.

Related

• [Feature request] Custom namespacing and branch naming conventions #1382 — custom namespacing & branch naming conventions.
• Mono repo considerations and best practices #581 — monorepo considerations (umbrella).

(Disclosure: AI-assisted investigation and drafting; reviewed by me.)

[PascalThuet]

Correction — the original premise (branch creation skipped) is wrong, my apologies.

Verified end-to-end on main (487af97): the installed create-new-feature-branch.sh loads core common.sh, which does not define has_git, so Git is detected via git -C "$REPO_ROOT" rev-parse --is-inside-work-tree — which walks up to the enclosing work tree. So in a single-root-.git monorepo the feature branch is created/switched in the shared root repo; it is not skipped, and there is no "Git repository not detected" message. My original repro sourced git-common.sh directly (which defines the stricter has_git); that isn't the script's normal load path.

I've re-scoped the title/description to the real residual: in a single-root-.git monorepo, member projects share the root repo's branch namespace while feature numbering is per-project. Closely related to #1382.