Improve git worktree session workflow

hooks/session-create.sh

@@ -2,8 +2,14 @@
 
 session_name=$(tmux display-message -p '#S')
 session_layout=~/.local/share/tmux/layouts/session-$session_name
+# Set by `session -p <project>`, which names the session after the project but
+# can't be relied on for the lookup above since tmux rewrites `.` in names.
+session_project=$(tmux show-environment -t "$session_name" TMUX_PROJECT 2>/dev/null |
+  sed -n 's/^TMUX_PROJECT=//p')
 if [ -f $session_layout ]; then
   $session_layout
+elif [ -n "$session_project" ]; then
+  ~/.local/share/tmux/layouts/session-project "$session_project"
 elif [ "$session_name" != "agent" ]; then
   tmux rename-window home
 fi

install.sh

@@ -31,6 +31,8 @@ symlink $HOME/.config/tmux/layouts/session-infra \
         $HOME/.local/share/tmux/layouts/session-infra
 symlink $HOME/.config/tmux/layouts/session-main \
         $HOME/.local/share/tmux/layouts/session-main
+symlink $HOME/.config/tmux/layouts/session-project \
+        $HOME/.local/share/tmux/layouts/session-project
 symlink $HOME/.config/tmux/layouts/session-visor \
         $HOME/.local/share/tmux/layouts/session-visor
 symlink $HOME/.config/tmux/layouts/session-work \

layouts/session-project

@@ -0,0 +1,35 @@
+#!/usr/bin/env zsh
+
+# usage: session-project <project>
+#
+# Layout for a session created by `session -p <project>`, where <project> is a
+# path in ~/Projects with the prefix removed. The session-created hook passes
+# the project along, taking it from the session environment.
+
+project=$1
+repo=$HOME/Projects/$project
+
+tmux rename-window home
+$(dirname $0)/window-auto
+
+# Without a project there is nothing but the home window, which is all a
+# session created directly from this layout's name can get.
+if [[ -z "$project" ]] || ! git -C "$repo" rev-parse --git-dir &>/dev/null; then
+  exit
+fi
+
+# The remote's default branch, falling back to whatever HEAD points at for
+# repositories without an origin/HEAD, e.g. those with no remote at all.
+branch=$(git -C "$repo" symbolic-ref --short refs/remotes/origin/HEAD 2>/dev/null)
+branch=${branch#origin/}
+if [[ -z "$branch" ]]; then
+  branch=$(git -C "$repo" symbolic-ref --short HEAD 2>/dev/null)
+fi
+if [[ -z "$branch" ]]; then
+  # Detached HEAD, name the window after the commit it sits on.
+  branch=$(git -C "$repo" rev-parse --short HEAD 2>/dev/null)
+fi
+
+tmux new-window -c "$repo"
+tmux rename-window "$branch"
+$(dirname $0)/window-auto

project.sh

@@ -57,7 +57,21 @@ if [[ "${1:-}" == --pick ]]; then
   ) || exit 0
   [ -n "$project" ] || exit 0
 
-  tmux new-window -n "$project" -c "$projects_dir/$project"
+  # Inside a session for this same project, e.g. one created by `session -p`,
+  # the slug only repeats the session name, so name the window after the branch
+  # checked out there instead — a worktree's whole identity. Everything up to
+  # the `@` is the clone the worktrees hang off, and tmux rewrote `.` and `:` in
+  # the session name, so match both before comparing.
+  window_name=$project
+  session=$(tmux display -p '#S')
+  root=${project%%@*}
+  if [ "${root//[.:]/_}" = "$session" ]; then
+    branch=$(git -C "$projects_dir/$project" symbolic-ref --short HEAD 2>/dev/null ||
+      git -C "$projects_dir/$project" rev-parse --short HEAD 2>/dev/null || true)
+    window_name=${branch:-$project}
+  fi
+
+  tmux new-window -n "$window_name" -c "$projects_dir/$project"
   ~/.local/share/tmux/layouts/window-auto
   exit
 fi

session.sh

@@ -4,9 +4,12 @@ set -e
 
 sessions=()
 
-# Get list of predefined session layouts
+# Get list of predefined session layouts, skipping session-project since it is
+# parameterized by `session -p <project>` rather than a session of its own
 for item in $HOME/.local/share/tmux/layouts/session-*; do
-  sessions+=(${item#$HOME/.local/share/tmux/layouts/session-})
+  layout=${item#$HOME/.local/share/tmux/layouts/session-}
+  [ "$layout" = project ] && continue
+  sessions+=($layout)
 done
 
 # Get list of existing sessions

theme.tmux

@@ -3,7 +3,10 @@ if -b '[ "$WSL_DISTRO_NAME" != "" ]' \
   'setw -g status-left " #(hostname)|#{WSL_DISTRO_NAME}|#{session_name}"' \
   'setw -g status-left " #(hostname -s)|#{session_name}"'
 setw -g status-left-style fg=colour240,bg=colour233
-setw -g status-left-length 32
+# Only a maximum, and the component is never padded out to it, so leave room
+# for the hostname beside a full session name: project sessions are named after
+# a path, e.g. modularml/modular@benie/some-branch.
+setw -g status-left-length 100
 
 # Centre status style
 setw -g status-style fg=colour240,bg=colour233