feat(ai-vterm): surface surviving tmux sessions in the project picker

Each project's tmux session is now named `<cj/ai-vterm-tmux-session-prefix><basename>` (default `aiv-`), so `tmux ls` can be filtered to AI-vterm's own sessions. After an Emacs crash the C-F9 project picker reads `tmux list-sessions`, matches surviving sessions back to their directories, and sorts those to the top: `[detached]` when only the tmux session is alive, `[running]` when a vterm buffer exists. The rest follow alphabetically. With tmux missing or no server running, it falls back to a plain alphabetical list. The picker's collection is a completion table that pins display order so Vertico doesn't re-sort and undo the active-first grouping.

The prefix is a new `defcustom` rather than `claude-`, which collides with hand-rolled tmux sessions. Sessions named before this change use the bare basename and won't be matched afterward. One `tmux kill-server` clears any orphans.

1 files changed, 71 insertions, 0 deletions

diff --git a/tests/test-ai-vterm--live-tmux-sessions.el b/tests/test-ai-vterm--live-tmux-sessions.el
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+++ b/tests/test-ai-vterm--live-tmux-sessions.el
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+;;; test-ai-vterm--live-tmux-sessions.el --- Tests for cj/--ai-vterm-live-tmux-sessions -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Lists the live tmux sessions that carry the AI-vterm prefix so the
+;; project picker can surface projects whose Claude session survived an
+;; Emacs crash.  tmux being absent or no server running is a normal
+;; "nothing to match" outcome, not an error -- the lister returns nil.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'ai-vterm)
+
+(defmacro test-ai-vterm--with-tmux-list (exit-code output &rest body)
+  "Run BODY with `process-file' mocked to a tmux list-sessions response.
+
+EXIT-CODE is what `process-file' returns (or the symbol `error' to
+make it signal).  OUTPUT is written to the stdout destination buffer."
+  (declare (indent 2))
+  `(cl-letf (((symbol-function 'process-file)
+              (lambda (_program _infile destination _display &rest _args)
+                (when (eq ,exit-code 'error)
+                  (error "tmux: command not found"))
+                (let ((buffer (cond
+                               ((eq destination t) (current-buffer))
+                               ((bufferp destination) destination)
+                               ((consp destination)
+                                (and (eq (car destination) t)
+                                     (current-buffer))))))
+                  (when (bufferp buffer)
+                    (with-current-buffer buffer (insert ,output))))
+                ,exit-code)))
+     ,@body))
+
+(ert-deftest test-ai-vterm--live-tmux-sessions-filters-to-prefix ()
+  "Normal: only sessions starting with the AI-vterm prefix come back."
+  (let ((cj/ai-vterm-tmux-session-prefix "aiv-"))
+    (test-ai-vterm--with-tmux-list 0 "aiv-foo\nrandom-session\naiv-bar\n"
+      (should (equal (cj/--ai-vterm-live-tmux-sessions)
+                     '("aiv-foo" "aiv-bar"))))))
+
+(ert-deftest test-ai-vterm--live-tmux-sessions-honors-custom-prefix ()
+  "Normal: a non-default prefix is what gets matched."
+  (let ((cj/ai-vterm-tmux-session-prefix "em-"))
+    (test-ai-vterm--with-tmux-list 0 "em-foo\naiv-bar\nem-baz\n"
+      (should (equal (cj/--ai-vterm-live-tmux-sessions)
+                     '("em-foo" "em-baz"))))))
+
+(ert-deftest test-ai-vterm--live-tmux-sessions-empty-output-yields-nil ()
+  "Boundary: a running server with no matching sessions yields nil."
+  (let ((cj/ai-vterm-tmux-session-prefix "aiv-"))
+    (test-ai-vterm--with-tmux-list 0 "other-a\nother-b\n"
+      (should (null (cj/--ai-vterm-live-tmux-sessions))))))
+
+(ert-deftest test-ai-vterm--live-tmux-sessions-no-server-yields-nil ()
+  "Error: tmux exits non-zero (no server running) -> nil, not a signal."
+  (let ((cj/ai-vterm-tmux-session-prefix "aiv-"))
+    (test-ai-vterm--with-tmux-list 1 "no server running on /tmp/tmux-1000/default\n"
+      (should (null (cj/--ai-vterm-live-tmux-sessions))))))
+
+(ert-deftest test-ai-vterm--live-tmux-sessions-tmux-missing-yields-nil ()
+  "Error: tmux not installed -> `process-file' signals; lister returns nil."
+  (let ((cj/ai-vterm-tmux-session-prefix "aiv-"))
+    (test-ai-vterm--with-tmux-list 'error ""
+      (should (null (cj/--ai-vterm-live-tmux-sessions))))))
+
+(provide 'test-ai-vterm--live-tmux-sessions)
+;;; test-ai-vterm--live-tmux-sessions.el ends here