Add init --sync and --prune for incremental monitor setup

`init` planned every file on every run and refused if any of them
existed, so attaching a new monitor could not be configured without
--force — which reallocated global workspace numbers by i3's current
output order and renumbered the monitors already in use.

- allocate_global_starts() keeps the block each known output already
  holds and gives new outputs the lowest free block; blocks of inactive
  outputs stay reserved.
- read_allocations()/parse_allocation() read those blocks back out of
  the generated files (inverse of render_workspaces_for_output).
- --sync writes only the missing files, --prune drops configs for
  outputs that are gone and frees their numbers.
- Files without the auto-generated header are never written or
  deleted, --force included.

Co-Authored-By: Claude <noreply@anthropic.com>

README.md

@@ -103,10 +103,36 @@ Useful flags:
 | `-n N` / `--count N` | 8 | Workspaces per output |
 | `--config-dir PATH` | `~/.config/i3/pi3-smart-workspace` | Where to write |
 | `--dry-run` | off | Print to stdout, don't touch the filesystem |
-| `--force` | off | Overwrite existing files |
+| `--sync` | off | Only write configs for outputs that don't have one yet |
+| `--force` | off | Regenerate every file from scratch (renumbers workspaces) |
+| `--prune` | off | Delete generated configs for outputs that are no longer active |
 
-Re-run `init --force` after plugging or unplugging a monitor to
+### Plugging in a new monitor
-regenerate the per-output folders.
+
+Run:
+
+```sh
+pi3-smart-workspace init --sync
+```
+
+`--sync` writes a `workspaces.conf` only for the outputs that don't have
+one yet, and gives the newcomer the lowest block of global workspace
+numbers that isn't already taken. The monitors you already use keep the
+numbers they have, so your muscle memory survives — which a plain
+`--force` regeneration would not guarantee, since that allocates numbers
+by i3's current output order and can shuffle everything.
+
+Configs for monitors that are merely switched off are left in place and
+their numbers stay reserved. Add `--prune` to delete them and free those
+numbers for a new screen:
+
+```sh
+pi3-smart-workspace init --sync --prune
+```
+
+Files that don't carry the `# Auto-generated by pi3-smart-workspace init`
+header are never overwritten or deleted, not even with `--force` — so
+anything you hand-tune in that directory is safe.
 
 ### Example config (manual)
 

pi3/smart_workspace.py

@@ -33,7 +33,7 @@ import pprint
 import re
 import sys
 from dataclasses import dataclass
-from typing import Iterable
+from typing import Iterable, Mapping
 
 import i3ipc
 
@@ -451,6 +451,101 @@ def render_bindings(count: int, mod: str = "$mod") -> str:
     return "".join(out)
 
 
+@dataclass(frozen=True)
+class Allocation:
+    """A block of global workspace numbers already handed to an output.
+
+    Attributes:
+        output: The output name the block belongs to.
+        start: First global workspace number in the block.
+        count: How many consecutive numbers the block covers.
+    """
+
+    output: str
+    start: int
+    count: int
+
+
+_ALLOC_OUTPUT_RE = re.compile(r"^\s*set\s+\$out_\w+\s+(\S+)\s*$", re.MULTILINE)
+_ALLOC_WS_RE = re.compile(r"^\s*set\s+\$ws_\w+\s+(\d+):\d+\s*$", re.MULTILINE)
+
+
+def parse_allocation(config_text: str) -> Allocation | None:
+    """Read back the output and global-number block from a generated file.
+
+    The inverse of :func:`render_workspaces_for_output`, used by
+    ``init --sync`` to keep the numbers a monitor already has instead of
+    reallocating them from scratch.
+
+    Args:
+        config_text: Contents of a ``workspaces.conf`` previously written
+            by ``init``.
+
+    Returns:
+        The :class:`Allocation` described by the file, or ``None`` if the
+        text doesn't contain both an ``$out_…`` alias and at least one
+        ``$ws_…`` alias (i.e. it isn't one of our generated files).
+    """
+    output_match = _ALLOC_OUTPUT_RE.search(config_text)
+    numbers = [int(m.group(1)) for m in _ALLOC_WS_RE.finditer(config_text)]
+    if output_match is None or not numbers:
+        return None
+    return Allocation(output_match.group(1), min(numbers), len(numbers))
+
+
+def allocate_global_starts(
+    outputs: Iterable[str],
+    existing: Mapping[str, Allocation],
+    count: int,
+) -> dict[str, int]:
+    """Decide each output's first global workspace number.
+
+    Outputs that already hold a block of the right size keep it, so
+    plugging in a new monitor never renumbers the ones you already use.
+    New outputs get the lowest block of ``count`` free numbers.
+
+    Blocks belonging to outputs in ``existing`` that aren't in ``outputs``
+    (an unplugged monitor) stay reserved — a screen that is merely
+    switched off must not lose its numbers to a newcomer. Drop those
+    entries from ``existing`` (what ``--prune`` does) to free them.
+
+    Args:
+        outputs: Names of the outputs to allocate for, in i3's order.
+        existing: Already-allocated blocks, keyed by output name.
+        count: Workspaces per output.
+
+    Returns:
+        ``{output_name: global_start}`` covering every name in ``outputs``.
+    """
+    if count < 1:
+        raise ValueError("count must be >= 1")
+
+    occupied: set[int] = set()
+    for alloc in existing.values():
+        occupied.update(range(alloc.start, alloc.start + alloc.count))
+
+    starts: dict[str, int] = {}
+    pending: list[str] = []
+    for name in outputs:
+        alloc = existing.get(name)
+        if alloc is not None and alloc.count == count:
+            starts[name] = alloc.start
+        else:
+            if alloc is not None:
+                # The requested block size changed (``-n``), so the old
+                # block can't be kept — release it and reallocate below.
+                occupied.difference_update(range(alloc.start, alloc.start + alloc.count))
+            pending.append(name)
+
+    for name in pending:
+        start = 1
+        while not occupied.isdisjoint(range(start, start + count)):
+            start += 1
+        starts[name] = start
+        occupied.update(range(start, start + count))
+    return starts
+
+
 @dataclass(frozen=True)
 class InitArgs:
     """Parsed CLI arguments for the ``init`` subcommand."""
@@ -459,6 +554,8 @@ class InitArgs:
     config_dir: pathlib.Path
     dry_run: bool
     force: bool
+    sync: bool
+    prune: bool
     debug: bool
 
 
@@ -466,19 +563,32 @@ def _planned_files(
     config_dir: pathlib.Path,
     outputs: list[tuple[str, Rect]],
     count: int,
+    starts: Mapping[str, int] | None = None,
 ) -> list[tuple[pathlib.Path, str]]:
     """Compute the (path, content) pairs that ``init`` would write.
 
     Pure function: no filesystem or i3 access. Each output gets a folder
     ``<config_dir>/<output_name>/workspaces.conf``; the shared keybindings
-    go in ``<config_dir>/bindings.conf``. Output order is preserved from
+    go in ``<config_dir>/bindings.conf``.
-    ``outputs`` so global workspace numbers are deterministic.
+
+    Args:
+        config_dir: Directory the generated files live in.
+        outputs: Active outputs, in i3's order.
+        count: Workspaces per output.
+        starts: Optional ``{output: global_start}`` map, typically from
+            :func:`allocate_global_starts`. When omitted, each output gets
+            a contiguous block based on its position in ``outputs`` —
+            deterministic, but it renumbers everything if the output order
+            changes.
     """
     files: list[tuple[pathlib.Path, str]] = [
         (config_dir / "bindings.conf", render_bindings(count)),
     ]
     for index, (output_name, _) in enumerate(outputs):
-        global_start = index * count + 1
+        if starts is not None:
+            global_start = starts[output_name]
+        else:
+            global_start = index * count + 1
         files.append(
             (
                 config_dir / output_name / "workspaces.conf",
@@ -488,15 +598,73 @@ def _planned_files(
     return files
 
 
+def _is_generated(path: pathlib.Path) -> bool:
+    """Return whether ``path`` carries our auto-generation header.
+
+    Anything else is treated as hand-written and never overwritten or
+    deleted, not even with ``--force``.
+    """
+    try:
+        return path.read_text().startswith(_AUTOGEN_HEADER)
+    except OSError:
+        return False
+
+
+def read_allocations(config_dir: pathlib.Path) -> dict[str, Allocation]:
+    """Read the global-number blocks already handed out under ``config_dir``.
+
+    Scans ``<config_dir>/*/workspaces.conf`` and parses each generated
+    file with :func:`parse_allocation`. Hand-edited or unreadable files
+    are skipped, so their numbers are *not* considered reserved.
+
+    Args:
+        config_dir: The (possibly non-existent) init config directory.
+
+    Returns:
+        ``{output_name: Allocation}``; empty if nothing has been generated
+        yet.
+    """
+    allocations: dict[str, Allocation] = {}
+    for path in sorted(config_dir.glob("*/workspaces.conf")):
+        if not _is_generated(path):
+            continue
+        try:
+            alloc = parse_allocation(path.read_text())
+        except OSError:
+            continue
+        if alloc is not None:
+            allocations[alloc.output] = alloc
+    return allocations
+
+
+def _prune_paths(config_dir: pathlib.Path, stale: Iterable[str]) -> list[pathlib.Path]:
+    """Return the generated ``workspaces.conf`` files of no-longer-active outputs."""
+    paths = []
+    for name in stale:
+        path = config_dir / name / "workspaces.conf"
+        if path.exists() and _is_generated(path):
+            paths.append(path)
+    return paths
+
+
 def run_init(args: InitArgs) -> None:
     """Generate per-output i3 workspace configs for the currently-active outputs.
 
+    Three write modes:
+
+    * default — write everything, but refuse if any target file exists.
+    * ``--sync`` — write only the files that are missing (the new
+      monitor), leaving existing outputs' numbers untouched.
+    * ``--force`` — regenerate everything from scratch, which reallocates
+      global workspace numbers by i3's current output order.
+
     Args:
         args: Parsed init-subcommand arguments.
 
     Raises:
-        RuntimeError: If no active outputs are detected, or if files
+        RuntimeError: If no active outputs are detected, if files already
-            already exist and ``--force`` was not passed.
+            exist and neither ``--sync`` nor ``--force`` was passed, or if
+            a target file exists but wasn't generated by us.
     """
     i3 = i3ipc.Connection()
     outputs = _active_outputs(i3)
@@ -504,27 +672,82 @@ def run_init(args: InitArgs) -> None:
         raise RuntimeError("no active outputs detected by i3")
 
     config_dir = args.config_dir.expanduser()
-    files = _planned_files(config_dir, outputs, args.count)
+    active_names = [name for name, _ in outputs]
+
+    allocations = read_allocations(config_dir)
+    stale = [name for name in allocations if name not in active_names]
+
+    if args.force:
+        # Explicit "start over": numbers follow i3's output order.
+        starts = None
+    else:
+        if args.prune:
+            for name in stale:
+                allocations.pop(name)
+        starts = allocate_global_starts(active_names, allocations, args.count)
+
+    files = _planned_files(config_dir, outputs, args.count, starts)
+    pruned = _prune_paths(config_dir, stale) if args.prune else []
+
+    if args.sync:
+        planned = [(path, content) for path, content in files if not path.exists()]
+    else:
+        planned = files
 
     if args.dry_run:
-        for path, content in files:
+        for path in pruned:
+            print(f"--- would remove {path} ---")
+        for path, content in planned:
             print(f"--- {path} ---")
             print(content, end="")
+        if not planned:
+            print("nothing to write; every active output already has a config")
         return
 
-    existing = [path for path, _ in files if path.exists()]
+    existing = [path for path, _ in planned if path.exists()]
     if existing and not args.force:
         listing = "\n  ".join(str(p) for p in existing)
         raise RuntimeError(
-            "refusing to overwrite existing files (pass --force to replace):\n  "
+            "refusing to overwrite existing files (pass --sync to only add "
-            + listing
+            "configs for new outputs, or --force to replace):\n  " + listing
         )
 
-    for path, content in files:
+    # Never clobber something the user wrote by hand — --force included.
+    hand_written = [path for path in existing if not _is_generated(path)]
+    if hand_written:
+        listing = "\n  ".join(str(p) for p in hand_written)
+        raise RuntimeError(
+            "refusing to overwrite files that were not generated by "
+            "`pi3-smart-workspace init` (move them aside first):\n  " + listing
+        )
+
+    for path, content in planned:
         path.parent.mkdir(parents=True, exist_ok=True)
         path.write_text(content)
         print(f"wrote {path}")
 
+    for path in pruned:
+        path.unlink()
+        print(f"removed {path}")
+        try:
+            path.parent.rmdir()
+        except OSError:
+            pass  # directory not empty — leave whatever else is in there
+
+    if not planned:
+        print("nothing to write; every active output already has a config")
+    if args.sync and stale and not args.prune:
+        listing = ", ".join(stale)
+        print(f"note: configs kept for inactive outputs: {listing} (--prune removes them)")
+    if args.sync:
+        bindings, bindings_content = files[0]
+        if bindings.exists() and _is_generated(bindings):
+            if bindings.read_text() != bindings_content:
+                print(
+                    f"note: {bindings} differs from what -n {args.count} would "
+                    "generate; pass --force to regenerate it"
+                )
+
     print()
     print("Add the following to your i3 config (typically ~/.config/i3/config):")
     print(f"  include {config_dir}/bindings.conf")
@@ -550,9 +773,22 @@ def _init_main(argv: list[str]) -> None:
         "--dry-run", action="store_true",
         help="Print generated configs to stdout instead of writing them.",
     )
-    parser.add_argument(
+    mode = parser.add_mutually_exclusive_group()
+    mode.add_argument(
+        "--sync", action="store_true",
+        help="Only write configs for outputs that don't have one yet, keeping "
+             "the workspace numbers of the outputs that do. Use this after "
+             "plugging in a new monitor.",
+    )
+    mode.add_argument(
         "--force", action="store_true",
-        help="Overwrite existing files in the config directory.",
+        help="Regenerate every file from scratch. This reallocates global "
+             "workspace numbers by i3's current output order.",
+    )
+    parser.add_argument(
+        "--prune", action="store_true",
+        help="Also delete generated configs for outputs that are no longer "
+             "active, freeing their workspace numbers.",
     )
     parser.add_argument(
         "-d", "--debug", action="store_true",
@@ -565,6 +801,8 @@ def _init_main(argv: list[str]) -> None:
         config_dir=parsed.config_dir,
         dry_run=parsed.dry_run,
         force=parsed.force,
+        sync=parsed.sync,
+        prune=parsed.prune,
         debug=parsed.debug,
     )
 

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "pi3-smart-workspace"
-version = "0.2.0"
+version = "0.3.0"
 description = "Switch i3 workspaces based on which output your mouse cursor is on."
 readme = "README.md"
 requires-python = ">=3.14"

tests/test_smart_workspace.py

@@ -1,13 +1,21 @@
 from textwrap import dedent
 
+import pytest
+
 from pi3.smart_workspace import (
+    Allocation,
+    InitArgs,
     Rect,
     _planned_files,
+    allocate_global_starts,
     expand_i3_includes,
     find_output_at_cursor,
+    parse_allocation,
     parse_workspaces_per_output,
+    read_allocations,
     render_bindings,
     render_workspaces_for_output,
+    run_init,
     sanitize_var_suffix,
 )
 
@@ -398,3 +406,248 @@ def test_init_output_parses_back_through_parser():
         "eDP-1": ["1:1", "2:2", "3:3"],
         "HDMI-A-0": ["4:1", "5:2", "6:3"],
     }
+
+
+# ---------------------------------------------------------------------------
+# incremental allocation (init --sync)
+# ---------------------------------------------------------------------------
+
+
+def test_parse_allocation_round_trips_render():
+    text = render_workspaces_for_output("HDMI-A-0", global_start=9, count=8)
+
+    assert parse_allocation(text) == Allocation("HDMI-A-0", 9, 8)
+
+
+def test_parse_allocation_ignores_unrelated_config():
+    assert parse_allocation("set $mod Mod4\nset $ws1 1:1\n") is None
+    assert parse_allocation("") is None
+
+
+def test_allocate_keeps_existing_outputs_and_appends_new():
+    """The bug this fixes: a new monitor must not renumber the old ones."""
+    existing = {"eDP-1": Allocation("eDP-1", 1, 8)}
+
+    # i3 reports the newcomer *first*, which used to push eDP-1 to 9..16.
+    starts = allocate_global_starts(["HDMI-A-0", "eDP-1"], existing, count=8)
+
+    assert starts == {"eDP-1": 1, "HDMI-A-0": 9}
+
+
+def test_allocate_reserves_blocks_of_currently_inactive_outputs():
+    """A switched-off monitor keeps its numbers unless it's pruned."""
+    existing = {
+        "eDP-1": Allocation("eDP-1", 1, 8),
+        "HDMI-A-0": Allocation("HDMI-A-0", 9, 8),  # unplugged right now
+    }
+
+    starts = allocate_global_starts(["eDP-1", "DP-1"], existing, count=8)
+
+    assert starts == {"eDP-1": 1, "DP-1": 17}
+
+
+def test_allocate_fills_the_hole_left_by_a_pruned_output():
+    existing = {"eDP-1": Allocation("eDP-1", 9, 8)}  # HDMI at 1..8 was pruned
+
+    starts = allocate_global_starts(["eDP-1", "DP-1"], existing, count=8)
+
+    assert starts == {"eDP-1": 9, "DP-1": 1}
+
+
+def test_allocate_reallocates_when_the_count_changes():
+    """A different -n means the old block no longer fits; it's released."""
+    existing = {
+        "eDP-1": Allocation("eDP-1", 1, 8),
+        "HDMI-A-0": Allocation("HDMI-A-0", 9, 8),
+    }
+
+    starts = allocate_global_starts(["eDP-1", "HDMI-A-0"], existing, count=4)
+
+    # Both 8-wide blocks are released and repacked tightly at the new width.
+    assert starts == {"eDP-1": 1, "HDMI-A-0": 5}
+
+
+def test_allocate_assigns_from_scratch_when_nothing_exists():
+    starts = allocate_global_starts(["eDP-1", "HDMI-A-0"], {}, count=3)
+
+    assert starts == {"eDP-1": 1, "HDMI-A-0": 4}
+
+
+def test_planned_files_honors_explicit_starts():
+    from pathlib import Path
+
+    outputs = [("HDMI-A-0", Rect(0, 0, 1920, 1080)), ("eDP-1", Rect(1920, 0, 1920, 1080))]
+
+    files = _planned_files(Path("/x"), outputs, count=8, starts={"eDP-1": 1, "HDMI-A-0": 9})
+
+    assert "set $ws_HDMI_A_0_1 9:1" in files[1][1]
+    assert "set $ws_eDP_1_1 1:1" in files[2][1]
+
+
+def test_read_allocations_skips_hand_written_files(tmp_path):
+    generated = tmp_path / "eDP-1" / "workspaces.conf"
+    generated.parent.mkdir()
+    generated.write_text(render_workspaces_for_output("eDP-1", 1, 8))
+
+    handwritten = tmp_path / "DP-1" / "workspaces.conf"
+    handwritten.parent.mkdir()
+    handwritten.write_text("set $out_DP_1 DP-1\nset $ws_DP_1_1 1:1\n")
+
+    assert read_allocations(tmp_path) == {"eDP-1": Allocation("eDP-1", 1, 8)}
+
+
+def test_read_allocations_on_missing_directory(tmp_path):
+    assert read_allocations(tmp_path / "nope") == {}
+
+
+# ---------------------------------------------------------------------------
+# run_init (with a stubbed i3 connection)
+# ---------------------------------------------------------------------------
+
+
+class _FakeOutput:
+    def __init__(self, name, rect):
+        self.name = name
+        self.rect = rect
+        self.active = True
+
+
+class _FakeConnection:
+    def __init__(self, outputs):
+        self._outputs = outputs
+
+    def get_outputs(self):
+        return self._outputs
+
+
+@pytest.fixture
+def fake_i3(monkeypatch):
+    """Install a stub i3 connection reporting the given active outputs."""
+    import pi3.smart_workspace as sw
+
+    def install(*names):
+        outputs = [
+            _FakeOutput(name, Rect(i * 1920, 0, 1920, 1080))
+            for i, name in enumerate(names)
+        ]
+        monkeypatch.setattr(
+            sw.i3ipc, "Connection", lambda *a, **kw: _FakeConnection(outputs)
+        )
+
+    return install
+
+
+def _init_args(config_dir, **overrides):
+    defaults = dict(
+        count=8, config_dir=config_dir, dry_run=False, force=False,
+        sync=False, prune=False, debug=True,
+    )
+    return InitArgs(**{**defaults, **overrides})
+
+
+def test_init_sync_adds_new_monitor_without_renumbering(tmp_path, fake_i3):
+    fake_i3("eDP-1")
+    run_init(_init_args(tmp_path))
+    before = (tmp_path / "eDP-1" / "workspaces.conf").read_text()
+
+    # New monitor shows up, and i3 lists it before the existing one.
+    fake_i3("HDMI-A-0", "eDP-1")
+    run_init(_init_args(tmp_path, sync=True))
+
+    assert (tmp_path / "eDP-1" / "workspaces.conf").read_text() == before
+    new = (tmp_path / "HDMI-A-0" / "workspaces.conf").read_text()
+    assert "set $ws_HDMI_A_0_1 9:1" in new
+    assert "set $ws_HDMI_A_0_8 16:8" in new
+
+
+def test_init_sync_result_parses_back_without_number_collisions(tmp_path, fake_i3):
+    fake_i3("eDP-1")
+    run_init(_init_args(tmp_path, count=3))
+    fake_i3("HDMI-A-0", "eDP-1")
+    run_init(_init_args(tmp_path, count=3, sync=True))
+
+    combined = "\n".join(
+        p.read_text() for p in sorted(tmp_path.glob("*/workspaces.conf"))
+    )
+    result = parse_workspaces_per_output(combined, ["eDP-1", "HDMI-A-0"])
+
+    assert result == {"eDP-1": ["1:1", "2:2", "3:3"], "HDMI-A-0": ["4:1", "5:2", "6:3"]}
+    # No global workspace number is claimed by two outputs.
+    numbers = [ws.split(":")[0] for names in result.values() for ws in names]
+    assert len(numbers) == len(set(numbers))
+
+
+def test_init_sync_is_a_noop_when_everything_exists(tmp_path, fake_i3):
+    fake_i3("eDP-1")
+    run_init(_init_args(tmp_path))
+    before = {p: p.read_text() for p in tmp_path.rglob("*.conf")}
+
+    run_init(_init_args(tmp_path, sync=True))
+
+    assert {p: p.read_text() for p in tmp_path.rglob("*.conf")} == before
+
+
+def test_init_without_sync_still_refuses_to_overwrite(tmp_path, fake_i3):
+    fake_i3("eDP-1")
+    run_init(_init_args(tmp_path))
+
+    fake_i3("HDMI-A-0", "eDP-1")
+    with pytest.raises(RuntimeError, match="--sync"):
+        run_init(_init_args(tmp_path))
+
+
+def test_init_force_renumbers_by_output_order(tmp_path, fake_i3):
+    fake_i3("eDP-1")
+    run_init(_init_args(tmp_path))
+
+    fake_i3("HDMI-A-0", "eDP-1")
+    run_init(_init_args(tmp_path, force=True))
+
+    assert "set $ws_HDMI_A_0_1 1:1" in (tmp_path / "HDMI-A-0" / "workspaces.conf").read_text()
+    assert "set $ws_eDP_1_1 9:1" in (tmp_path / "eDP-1" / "workspaces.conf").read_text()
+
+
+def test_init_force_refuses_to_clobber_hand_written_files(tmp_path, fake_i3):
+    fake_i3("eDP-1")
+    target = tmp_path / "eDP-1" / "workspaces.conf"
+    target.parent.mkdir(parents=True)
+    target.write_text("# mine, hand-tuned\nset $out_eDP_1 eDP-1\n")
+
+    with pytest.raises(RuntimeError, match="not generated"):
+        run_init(_init_args(tmp_path, force=True))
+
+    assert target.read_text() == "# mine, hand-tuned\nset $out_eDP_1 eDP-1\n"
+
+
+def test_init_prune_removes_inactive_output_and_frees_its_numbers(tmp_path, fake_i3):
+    fake_i3("eDP-1", "HDMI-A-0")
+    run_init(_init_args(tmp_path))
+    assert (tmp_path / "HDMI-A-0").exists()
+
+    # HDMI unplugged, DP-1 plugged in instead.
+    fake_i3("eDP-1", "DP-1")
+    run_init(_init_args(tmp_path, sync=True, prune=True))
+
+    assert not (tmp_path / "HDMI-A-0").exists()
+    # DP-1 reuses the block HDMI-A-0 gave up rather than starting at 17.
+    assert "set $ws_DP_1_1 9:1" in (tmp_path / "DP-1" / "workspaces.conf").read_text()
+
+
+def test_init_prune_leaves_hand_written_files_alone(tmp_path, fake_i3):
+    fake_i3("eDP-1")
+    run_init(_init_args(tmp_path))
+    handwritten = tmp_path / "HDMI-A-0" / "workspaces.conf"
+    handwritten.parent.mkdir()
+    handwritten.write_text("# mine\n")
+
+    run_init(_init_args(tmp_path, sync=True, prune=True))
+
+    assert handwritten.exists()
+
+
+def test_init_dry_run_touches_nothing(tmp_path, fake_i3):
+    fake_i3("eDP-1")
+
+    run_init(_init_args(tmp_path, dry_run=True))
+
+    assert list(tmp_path.iterdir()) == []