Introduce "partials" to support config inheritance - #987

Metadata

This is a first attempt at addressing the "project config inheritance" feature requested in #979

Problem / Motivation

This change set introduces a new top-level config property called "partials". It allows the user to specify a list of partial or base (I'm not satisfied with either name yet) config files that their project config will extend.

This is still WIP but the current strategy collapses all top-level config options and the last specified in the list wins. As far as windows go, the current iteration accrues them as it processes the partials and eventually the project config and doesn't attempt to do anything clever about merging windows with the same name, deduping commands, etc. There are a few ways this could be made better but this initial pass is simple and unsurprising. We could potentially make the window treatment configurable but I think that's best left for a future PR.

Errors resulting from the parsing and merging of partials bubble up to the exsting #load exception handler and are handled in the same way: tmuxinator exits with an error message. We could handle the errors and continue with just the project but, again, I think simple and obvious is the preferred approach.

Solution

In practice, the feature looks like:

# foo.yaml
partials:
  - "/home/peter/.config/tmuxinator/partial-1.yaml"
  - "/home/peter/.config/tmuxinator/partial-2.yaml"
name: foo
attach: true
windows:
  - editor:
      layout: main-vertical
      panes:
        - editor:
          - vim

# partial-1.yaml
pre:
  - echo "partial is working"
  
# partial-2.yaml 
socket_name: qux
windows:
  - editor:
      layout: main-vertical
      panes:
        - editor:
          - emacs

The resulting tmuxinator commands are as follows:

#!/bin/bash


  # Clear rbenv variables before starting tmux
  unset RBENV_VERSION
  unset RBENV_DIR

  tmux -L qux start-server;

cd .

# Run on_project_start command.



  # Run pre command.
  

  # Run on_project_first_start command.
  

  tmux -L qux new-session -d -s foo -n editor



  # Create windows.
  tmux -L qux new-window  -k -t foo:0 -n editor
  tmux -L qux new-window  -k -t foo:1 -n editor


  # Window "editor"


  tmux -L qux select-pane -t foo:0.0 -T editor
  tmux -L qux send-keys -t foo:0.0 emacs C-m

  tmux -L qux select-layout -t foo:0 tiled

  tmux -L qux select-layout -t foo:0 main-vertical
  tmux -L qux select-pane -t foo:0.0


  # Window "editor"


  tmux -L qux select-pane -t foo:1.0 -T editor
  tmux -L qux send-keys -t foo:1.0 vim C-m

  tmux -L qux select-layout -t foo:1 tiled

  tmux -L qux select-layout -t foo:1 main-vertical
  tmux -L qux select-pane -t foo:1.0


  tmux -L qux select-window -t foo:0
  tmux -L qux select-pane -t foo:0.0

  if [ -z "$TMUX" ]; then
    tmux -L qux -u attach-session -t foo
  else
    tmux -L qux -u switch-client -t foo
  fi



# Run on_project_exit command.

TODO

• Use project config lookup for partials so full paths aren't required
• Decide if the current window treatment is satisfactory
• Test degenerate cases:
  • Malformed partial
  • Missing partial
• Change "partials" to ... something else?
• Anything else?

Any thoughts about this feature at either the micro or macro levels, @tmuxinator/tmuxinator?