add the ability to append windows to a session

Modifies the behaviour when starting a session from within an existing
tmux session: the user is given the choice to switch to new session, do
nothing, or append to current session.

Author: will-ockmore

docs/cli.rst

@@ -169,6 +169,23 @@ directory may be loaded with:
 
     $ tmuxp load .
 
+If you try to load a config file from within a tmux session, it will ask you
+if you want to load and attach to the new session, or just load detached.
+You can also load a config file and append the windows to the current active session.
+
+::
+
+    Already inside TMUX, switch to session? yes/no
+    Or (a)ppend windows in the current active session?
+    [y/n/a]:
+
+All of these options can be preselected to skip the prompt:
+
+.. code-block:: bash
+    $ tmuxp load -y config # load attached
+    $ tmuxp load -d config # load detached
+    $ tmuxp load -a config # append windows
+
 Multiple sessions can be loaded at once. The first ones will be created
 without being attached. The last one will be attached if there is no
 ``-d`` flag on the command line.

docs/quickstart.rst

@@ -55,7 +55,8 @@ Load multiple tmux sessions at once:
     $ tmuxp load example.yaml anothersession.yaml
 
 tmuxp will offer to ``switch-client`` for you if you're already in a
-session.
+session. You can also load a configuration, and append the windows to
+the current active session.
 
 You can also have a custom tmuxp config directory by setting the
 ``TMUX_CONFIGDIR`` in your environment variables.

tests/fixtures/workspacebuilder/three_windows.yaml

@@ -0,0 +1,14 @@
+session_name: sample_three_windows
+windows:
+- window_name: first
+  panes:
+    - shell_command:
+      - echo 'first window'
+- window_name: second
+  panes:
+    - shell_command:
+      - echo 'second window'
+- window_name: third
+  panes:
+    - shell_command:
+      - echo 'third window'

tests/fixtures/workspacebuilder/two_windows.yaml

@@ -0,0 +1,10 @@
+session_name: sample_two_windows
+windows:
+- window_name: first
+  panes:
+    - shell_command:
+      - echo 'first window'
+- window_name: second
+  panes:
+    - shell_command:
+      - echo 'second window'

tests/test_workspacebuilder.py

@@ -779,3 +779,60 @@ def test_plugin_system_multiple_plugins(session):
     # override methods are currently written
     proc = session.cmd('display-message', '-p', "'#W'")
     assert proc.stdout[0] == "'mp_test_awf'"
+
+
+def test_load_configs_same_session(server):
+    yaml_config = loadfixture("workspacebuilder/three_windows.yaml")
+    sconfig = kaptan.Kaptan(handler='yaml')
+    sconfig = sconfig.import_config(yaml_config).get()
+
+    builder = WorkspaceBuilder(sconf=sconfig, server=server)
+    builder.build()
+
+    assert len(server.sessions) == 1
+    assert len(server.sessions[0]._windows) == 3
+
+    yaml_config = loadfixture("workspacebuilder/two_windows.yaml")
+
+    sconfig = kaptan.Kaptan(handler='yaml')
+    sconfig = sconfig.import_config(yaml_config).get()
+
+    builder = WorkspaceBuilder(sconf=sconfig, server=server)
+    builder.build()
+    assert len(server.sessions) == 2
+    assert len(server.sessions[1]._windows) == 2
+
+    yaml_config = loadfixture("workspacebuilder/two_windows.yaml")
+
+    sconfig = kaptan.Kaptan(handler='yaml')
+    sconfig = sconfig.import_config(yaml_config).get()
+
+    builder = WorkspaceBuilder(sconf=sconfig, server=server)
+    builder.build(server.sessions[1], True)
+
+    assert len(server.sessions) == 2
+    assert len(server.sessions[1]._windows) == 4
+
+
+def test_load_configs_separate_sessions(server):
+    yaml_config = loadfixture("workspacebuilder/three_windows.yaml")
+    sconfig = kaptan.Kaptan(handler='yaml')
+    sconfig = sconfig.import_config(yaml_config).get()
+
+    builder = WorkspaceBuilder(sconf=sconfig, server=server)
+    builder.build()
+
+    assert len(server.sessions) == 1
+    assert len(server.sessions[0]._windows) == 3
+
+    yaml_config = loadfixture("workspacebuilder/two_windows.yaml")
+
+    sconfig = kaptan.Kaptan(handler='yaml')
+    sconfig = sconfig.import_config(yaml_config).get()
+
+    builder = WorkspaceBuilder(sconf=sconfig, server=server)
+    builder.build()
+
+    assert len(server.sessions) == 2
+    assert len(server.sessions[0]._windows) == 3
+    assert len(server.sessions[1]._windows) == 2

tmuxp/cli.py

@@ -448,7 +448,6 @@ def _reattach(builder):
 
     If not, ``tmux attach-session`` loads the client to the target session.
     """
-
     for plugin in builder.plugins:
         plugin.reattach(builder.session)
         proc = builder.session.cmd('display-message', '-p', "'#S'")
@@ -462,6 +461,85 @@ def _reattach(builder):
         builder.session.attach_session()
 
 
+def _load_attached(builder, detached):
+    """
+    Load config in new session and attach
+
+    Parameters
+    ----------
+    builder: :class:`workspacebuilder.WorkspaceBuilder`
+    detached : bool
+    """
+    builder.build()
+
+    if 'TMUX' in os.environ:  # tmuxp ran from inside tmux
+        # unset TMUX, save it, e.g. '/tmp/tmux-1000/default,30668,0'
+        tmux_env = os.environ.pop('TMUX')
+
+        if has_gte_version('2.6'):
+            set_layout_hook(builder.session, 'client-session-changed')
+
+        builder.session.switch_client()  # switch client to new session
+
+        os.environ['TMUX'] = tmux_env  # set TMUX back again
+    else:
+        if has_gte_version('2.6'):
+            # if attaching for first time
+            set_layout_hook(builder.session, 'client-attached')
+
+            # for cases where user switches client for first time
+            set_layout_hook(builder.session, 'client-session-changed')
+
+        if not detached:
+            builder.session.attach_session()
+
+
+def _load_detached(builder):
+    """
+    Load config in new session but don't attach
+
+    Parameters
+    ----------
+    builder: :class:`workspacebuilder.WorkspaceBuilder`
+    """
+    builder.build()
+
+    if has_gte_version('2.6'):  # prepare for both cases
+        set_layout_hook(builder.session, 'client-attached')
+        set_layout_hook(builder.session, 'client-session-changed')
+
+    print('Session created in detached state.')
+
+
+def _load_append_windows_to_current_session(builder):
+    """
+    Load config as new windows in current session
+
+    Parameters
+    ----------
+    builder: :class:`workspacebuilder.WorkspaceBuilder`
+    """
+    current_attached_session = builder.find_current_attached_session()
+    builder.build(current_attached_session, append=True)
+    if has_gte_version('2.6'):  # prepare for both cases
+        set_layout_hook(builder.session, 'client-attached')
+        set_layout_hook(builder.session, 'client-session-changed')
+
+
+def _setup_plugins(builder):
+    """
+    Runs after before_script
+
+    Parameters
+    ----------
+    builder: :class:`workspacebuilder.WorkspaceBuilder`
+    """
+    for plugin in builder.plugins:
+        plugin.before_script(builder.session)
+
+    return builder.session
+
+
 def load_workspace(
     config_file,
     socket_name=None,
@@ -470,6 +548,7 @@ def load_workspace(
     colors=None,
     detached=False,
     answer_yes=False,
+    append=False,
 ):
     """
     Load a tmux "workspace" session via tmuxp file.
@@ -490,7 +569,11 @@ def load_workspace(
     detached : bool
         Force detached state. default False.
     answer_yes : bool
-        Assume yes when given prompt. default False.
+        Assume yes when given prompt to attach in new session.
+        Default False.
+    append : bool
+       Assume current when given prompt to append windows in same session.
+       Default False.
 
     Notes
     -----
@@ -595,9 +678,8 @@ def load_workspace(
 
     session_name = sconfig['session_name']
 
-    # if the session already exists, prompt the user to attach. tmuxp doesn't
-    # support incremental session building or appending (yet, PR's welcome!)
-    if builder.session_exists(session_name):
+    # if the session already exists, prompt the user to attach
+    if builder.session_exists(session_name) and not append:
         if not detached and (
             answer_yes
             or click.confirm(
@@ -610,38 +692,37 @@ def load_workspace(
         return
 
     try:
-        builder.build()  # load tmux session via workspace builder
-
-        if 'TMUX' in os.environ:  # tmuxp ran from inside tmux
-            if not detached and (
-                answer_yes or click.confirm('Already inside TMUX, switch to session?')
-            ):
-                # unset TMUX, save it, e.g. '/tmp/tmux-1000/default,30668,0'
-                tmux_env = os.environ.pop('TMUX')
-
-                if has_gte_version('2.6'):
-                    set_layout_hook(builder.session, 'client-session-changed')
-
-                builder.session.switch_client()  # switch client to new session
+        if detached:
+            _load_detached(builder)
+            return _setup_plugins(builder)
 
-                os.environ['TMUX'] = tmux_env  # set TMUX back again
-                return builder.session
-            else:  # session created in the background, from within tmux
-                if has_gte_version('2.6'):  # prepare for both cases
-                    set_layout_hook(builder.session, 'client-attached')
-                    set_layout_hook(builder.session, 'client-session-changed')
+        if append:
+            if 'TMUX' in os.environ:  # tmuxp ran from inside tmux
+                _load_append_windows_to_current_session(builder)
+            else:
+                _load_attached(builder, detached)
 
-                sys.exit('Session created in detached state.')
-        else:  # tmuxp ran from inside tmux
-            if has_gte_version('2.6'):
-                # if attaching for first time
-                set_layout_hook(builder.session, 'client-attached')
+            return _setup_plugins(builder)
 
-                # for cases where user switches client for first time
-                set_layout_hook(builder.session, 'client-session-changed')
+        # append and answer_yes have no meaning if specified together
+        elif answer_yes:
+            _load_attached(builder, detached)
+            return _setup_plugins(builder)
 
-            if not detached:
-                builder.session.attach_session()
+        if 'TMUX' in os.environ:  # tmuxp ran from inside tmux
+            msg = "Already inside TMUX, switch to session? yes/no\n"\
+            "Or (a)ppend windows in the current active session?\n[y/n/a]"
+            options = ['y', 'n', 'a']
+            choice = click.prompt(msg, value_proc=_validate_choices(options))
+
+            if choice == 'y':
+                _load_attached(builder, detached)
+            elif choice == 'a':
+                _load_append_windows_to_current_session(builder)
+            else:
+                _load_detached(builder)
+        else:
+            _load_attached(builder, detached)
 
     except exc.TmuxpException as e:
         import traceback
@@ -663,11 +744,8 @@ def load_workspace(
         else:
             sys.exit()
 
-    # Runs after before_script
-    for plugin in builder.plugins:
-        plugin.before_script(builder.session)
+    return _setup_plugins(builder)
 
-    return builder.session
 
 
 @click.group(context_settings={'obj': {}})
@@ -923,6 +1001,12 @@ def command_freeze(session_name, socket_name, socket_path, force):
 @click.option(
     '-d', 'detached', help='Load the session without attaching it', is_flag=True
 )
+@click.option(
+    '-a',
+    'append',
+    help='Load configuration, appending windows to the current session',
+    is_flag=True
+)
 @click.option(
     'colors',
     '-2',
@@ -945,6 +1029,7 @@ def command_load(
     new_session_name,
     answer_yes,
     detached,
+    append,
     colors,
     log_file,
 ):
@@ -983,6 +1068,7 @@ def command_load(
         'answer_yes': answer_yes,
         'colors': colors,
         'detached': detached,
+        'append': append,
     }
 
     if not config: