feat(josh-sync): rename --subfolder now git mv's the actual directory

Previously --subfolder only repointed .josh-sync.yml, leaving the working
tree out of sync with the new path until a later filter-change
reconciliation happened to catch it. Now validates the old subfolder
exists and is tracked by git (proof it's actually managed by josh-sync)
and the new one doesn't already exist, then git mv's it — staged, not
committed, alongside the config edit. Idempotent on resume. Bumps to
v2.4.0.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TNXgcFWVgSh3wkQS55cCX6

tests/unit/rename.bats

@@ -2,13 +2,17 @@
 # tests/unit/rename.bats — Config-only rename tests (name/subfolder edits,
 # validation, resumability field checks).
 #
-# No real git remote is touched here: `--subrepo-url` renames (which need a
+# No real git REMOTE is touched here: `--subrepo-url` renames (which need a
 # reachability check) and all actual state-branch migration behavior are
 # covered by tests/unit/rename_e2e.bats instead. Every call below either
 # omits --subrepo-url or passes assume_yes=true with no state branch present,
-# so the concurrency/state-conflict checks run against a non-git tmpdir and
-# harmlessly no-op (git commands fail closed, caught by `|| return 0`/`|| true`
-# in lib/state.sh and lib/rename.sh).
+# so the concurrency/state-conflict checks run against a repo with no
+# "origin" remote and harmlessly no-op (git commands fail closed, caught by
+# `|| return 0`/`|| true` in lib/state.sh and lib/rename.sh).
+#
+# `--subfolder` renames DO need a real (local, remote-less) git repo, since
+# _rename_validate_subfolder_move/_rename_move_subfolder use `git ls-files`
+# and `git mv` against the actual working tree — see init_local_git_repo.
 
 setup() {
   export JOSH_SYNC_ROOT="$(cd "$BATS_TEST_DIRNAME/../.." && pwd)"
@@ -21,6 +25,14 @@ setup() {
   FIXTURES="$JOSH_SYNC_ROOT/tests/fixtures"
 }
 
+# Init a plain local git repo in cwd — no remote, just enough for
+# `git ls-files`/`git mv` to work. Use for any test touching --subfolder.
+init_local_git_repo() {
+  git init -q .
+  git config user.name "Test User"
+  git config user.email "test@test.local"
+}
+
 # ─── _rename_validate_name ─────────────────────────────────────────
 
 @test "_rename_validate_name rejects a name with a slash" {
@@ -82,9 +94,14 @@ setup() {
   [ "$app_b_subfolder" = "services/app-b" ]
 }
 
-@test "rename_target --subfolder re-derives josh_filter" {
+@test "rename_target --subfolder re-derives josh_filter and git mv's the directory" {
   cd "$(mktemp -d)"
   cp "$FIXTURES/minimal.yml" .josh-sync.yml
+  init_local_git_repo
+  mkdir -p services/example
+  echo "content" > services/example/file.txt
+  git add -A
+  git commit -q -m "seed"
   parse_config ".josh-sync.yml"
 
   rename_target "example" "" "services/relocated" "" ".josh-sync.yml" false true false
@@ -94,11 +111,22 @@ setup() {
   [ "$filter" = ":/services/relocated" ]
   subfolder=$(echo "$JOSH_SYNC_TARGETS" | jq -r '.[0].subfolder')
   [ "$subfolder" = "services/relocated" ]
+
+  [ ! -e services/example ]
+  [ -f services/relocated/file.txt ]
+  # git mv stages the rename — should be staged, not left as an untracked file.
+  staged=$(git diff --cached --name-only)
+  [[ "$staged" == *"relocated/file.txt"* ]]
 }
 
-@test "rename_target combining --name and --subfolder updates both fields" {
+@test "rename_target combining --name and --subfolder updates both fields and moves the directory" {
   cd "$(mktemp -d)"
   cp "$FIXTURES/minimal.yml" .josh-sync.yml
+  init_local_git_repo
+  mkdir -p services/example
+  echo "content" > services/example/file.txt
+  git add -A
+  git commit -q -m "seed"
   parse_config ".josh-sync.yml"
 
   rename_target "example" "relocated" "services/relocated" "" ".josh-sync.yml" false true false
@@ -110,6 +138,65 @@ setup() {
   [ "$name" = "relocated" ]
   [ "$subfolder" = "services/relocated" ]
   [ "$filter" = ":/services/relocated" ]
+
+  [ ! -e services/example ]
+  [ -f services/relocated/file.txt ]
+}
+
+# ─── subfolder move validation/idempotency ─────────────────────────
+
+@test "_rename_validate_subfolder_move dies when the old subfolder doesn't exist" {
+  cd "$(mktemp -d)"
+  init_local_git_repo
+  run _rename_validate_subfolder_move "services/ghost" "services/new"
+  [ "$status" -ne 0 ]
+  [[ "$output" == *"does not exist"* ]]
+}
+
+@test "_rename_validate_subfolder_move dies when the old subfolder isn't tracked by git" {
+  cd "$(mktemp -d)"
+  init_local_git_repo
+  mkdir -p services/untracked
+  echo "x" > services/untracked/file.txt
+  run _rename_validate_subfolder_move "services/untracked" "services/new"
+  [ "$status" -ne 0 ]
+  [[ "$output" == *"not managed by josh-sync"* ]]
+}
+
+@test "_rename_validate_subfolder_move dies when the new subfolder already exists" {
+  cd "$(mktemp -d)"
+  init_local_git_repo
+  mkdir -p services/old services/new
+  echo "x" > services/old/file.txt
+  echo "y" > services/new/file.txt
+  git add -A
+  git commit -q -m "seed"
+  run _rename_validate_subfolder_move "services/old" "services/new"
+  [ "$status" -ne 0 ]
+  [[ "$output" == *"already exists"* ]]
+}
+
+@test "_rename_validate_subfolder_move is a no-op when the move already happened" {
+  cd "$(mktemp -d)"
+  init_local_git_repo
+  mkdir -p services/new
+  echo "x" > services/new/file.txt
+  git add -A
+  git commit -q -m "seed"
+  run _rename_validate_subfolder_move "services/old" "services/new"
+  [ "$status" -eq 0 ]
+}
+
+@test "_rename_move_subfolder is idempotent when re-run after the move already happened" {
+  cd "$(mktemp -d)"
+  init_local_git_repo
+  mkdir -p services/new
+  echo "x" > services/new/file.txt
+  git add -A
+  git commit -q -m "seed"
+  run _rename_move_subfolder "services/old" "services/new"
+  [ "$status" -eq 0 ]
+  [ -f services/new/file.txt ]
 }
 
 @test "rename_target rejects a new name colliding with an existing target" {

tests/unit/rename_e2e.bats

@@ -356,6 +356,11 @@ state_branch_commit_count() {
   write_billing_config "$subrepo_bare"
   parse_config ".josh-sync.yml"
 
+  mkdir -p services/billing
+  echo "content" > services/billing/file.txt
+  git add -A
+  git commit -q -m "seed billing subfolder"
+
   seed_state_commit "" "billing/main.json" '{"last_forward":{"mono_sha":"abc","josh_filter":":/services/billing"}}'
 
   # --force: the seed_state_commit above just wrote a "recent" commit under
@@ -379,4 +384,65 @@ state_branch_commit_count() {
 
   msg=$(git log "origin/${STATE_BRANCH}" -1 --format=%s)
   [ "$msg" = "state: rename billing -> payments" ]
+
+  [ ! -e services/billing ]
+  [ -f services/payments/file.txt ]
+}
+
+# ─── rename_target: subfolder move (git mv in the monorepo tree) ──
+
+@test "rename_target git mv's the subfolder and dies if the old path isn't tracked" {
+  setup_state_monorepo
+  local subrepo_bare
+  subrepo_bare=$(make_bare_repo "billing-sub")
+  write_billing_config "$subrepo_bare"
+  parse_config ".josh-sync.yml"
+
+  # services/billing was never created/tracked — not "managed by josh-sync".
+  run rename_target "billing" "" "services/relocated" "" ".josh-sync.yml" false true false
+  [ "$status" -ne 0 ]
+  [[ "$output" == *"does not exist"* ]]
+}
+
+@test "rename_target dies when the new subfolder path already exists" {
+  setup_state_monorepo
+  local subrepo_bare
+  subrepo_bare=$(make_bare_repo "billing-sub")
+  write_billing_config "$subrepo_bare"
+  parse_config ".josh-sync.yml"
+
+  mkdir -p services/billing services/relocated
+  echo "old" > services/billing/file.txt
+  echo "existing" > services/relocated/other.txt
+  git add -A
+  git commit -q -m "seed"
+
+  run rename_target "billing" "" "services/relocated" "" ".josh-sync.yml" false true false
+  [ "$status" -ne 0 ]
+  [[ "$output" == *"already exists"* ]]
+  # nothing should have moved
+  [ -f services/billing/file.txt ]
+}
+
+@test "rename_target moves the subfolder via git mv, staged but not committed" {
+  setup_state_monorepo
+  local subrepo_bare
+  subrepo_bare=$(make_bare_repo "billing-sub")
+  write_billing_config "$subrepo_bare"
+  parse_config ".josh-sync.yml"
+
+  mkdir -p services/billing
+  echo "content" > services/billing/file.txt
+  git add -A
+  git commit -q -m "seed"
+
+  rename_target "billing" "" "services/relocated" "" ".josh-sync.yml" false true false
+
+  [ ! -e services/billing ]
+  [ -f services/relocated/file.txt ]
+  staged=$(git diff --cached --name-only)
+  [[ "$staged" == *"relocated/file.txt"* ]]
+  # Not committed — mirrors the config edit, left for the user to review.
+  head_files=$(git show --name-only --format= HEAD)
+  [[ "$head_files" != *"relocated"* ]]
 }