fix(telega): alert on server death and pin the container image

- A dead telega-server now raises a persistent desktop notification.
- The container image is pinned by digest, not by tag.
- A clean telega exit stays silent, so quitting never pages.

telega reports an abnormal server exit through the echo area, where it scrolls away unseen. That's how a dead server reads as a quiet Telegram. The scan stops partway, and the chats it never reached look empty. It's happened twice. Both times something downstream caught it rather than the failure announcing itself.

telega pins its image only when its TDLib min and max versions match. Here the max is nil, so the image was always the latest tag. A floating tag against a fixed elpa package means the server can change underneath it with nothing announcing that either.

Neither change fixes the crash. The root cause is still open. The assertion is a plist parse failure. Its coredump shows a smashed stack, which reads more like memory corruption than a parse rejection.

I didn't pull a newer image, which was the other half of the plan. The pull was meant to test whether an old server was failing against newer elisp. The frozen image ships libtdjson 1.8.64, exactly the version this telega requires. That theory no longer holds, so pulling would trade a matched server for an unknown one.

1 files changed, 93 insertions, 0 deletions

diff --git a/tests/test-telega-config--docker-pin.el b/tests/test-telega-config--docker-pin.el
new file mode 100644
index 00000000..894dbfdd
--- /dev/null
+++ b/tests/test-telega-config--docker-pin.el
@@ -0,0 +1,93 @@
+;;; test-telega-config--docker-pin.el --- Tests for the telega docker image pin -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Tests for pinning the telega-server container image.
+;;
+;; telega infers its image from `telega-tdlib-min-version' and only pins to a
+;; version tag when min and max versions are equal and the version ends in
+;; ".0".  This config has min "1.8.64" and max nil, so the inference always
+;; falls through to "zevlg/telega-server:latest" -- a moving tag that can
+;; swap the server out from under a fixed elisp version without notice.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'telega-config)
+
+;; -- cj/--telega-docker-pinned-image -----------------------------------------
+
+(ert-deftest test-telega-config-pin-returns-configured-reference ()
+  "Normal: a configured pin is returned verbatim."
+  (let ((cj/telega-docker-image "zevlg/telega-server@sha256:abc123"))
+    (should (equal (cj/--telega-docker-pinned-image)
+                   "zevlg/telega-server@sha256:abc123"))))
+
+(ert-deftest test-telega-config-pin-nil-when-unset ()
+  "Boundary: no pin returns nil so telega's own inference stays in charge."
+  (let ((cj/telega-docker-image nil))
+    (should-not (cj/--telega-docker-pinned-image))))
+
+(ert-deftest test-telega-config-pin-nil-for-empty-string ()
+  "Boundary: an empty or whitespace pin is not a reference.
+An empty string would otherwise reach the docker command line as a blank
+image argument, which fails in a way that looks unrelated to this setting."
+  (let ((cj/telega-docker-image ""))
+    (should-not (cj/--telega-docker-pinned-image)))
+  (let ((cj/telega-docker-image "   "))
+    (should-not (cj/--telega-docker-pinned-image))))
+
+(ert-deftest test-telega-config-pin-nil-for-non-string ()
+  "Error: a non-string pin is ignored rather than passed to the shell."
+  (let ((cj/telega-docker-image 'latest))
+    (should-not (cj/--telega-docker-pinned-image)))
+  (let ((cj/telega-docker-image 42))
+    (should-not (cj/--telega-docker-pinned-image))))
+
+(ert-deftest test-telega-config-pin-trims-surrounding-whitespace ()
+  "Boundary: a pin with stray whitespace is trimmed, not rejected.
+A trailing newline is easy to introduce when pasting a digest from docker."
+  (let ((cj/telega-docker-image "  zevlg/telega-server@sha256:abc123\n"))
+    (should (equal (cj/--telega-docker-pinned-image)
+                   "zevlg/telega-server@sha256:abc123"))))
+
+;; -- cj/--telega-docker-image-name (the advice) ------------------------------
+
+(ert-deftest test-telega-config-image-advice-prefers-the-pin ()
+  "Normal: with a pin set, the advice returns it instead of calling telega."
+  (let ((cj/telega-docker-image "zevlg/telega-server@sha256:abc123")
+        (called nil))
+    (should (equal (cj/--telega-docker-image-name
+                    (lambda () (setq called t) "zevlg/telega-server:latest"))
+                   "zevlg/telega-server@sha256:abc123"))
+    (should-not called)))
+
+(ert-deftest test-telega-config-image-advice-delegates-without-a-pin ()
+  "Boundary: with no pin, telega's own inference is used unchanged.
+Removing the pin must restore stock behavior rather than break the image
+name, so this stays a reversible setting."
+  (let ((cj/telega-docker-image nil))
+    (should (equal (cj/--telega-docker-image-name
+                    (lambda () "zevlg/telega-server:latest"))
+                   "zevlg/telega-server:latest"))))
+
+(ert-deftest test-telega-config-image-advice-is-named-and-removable ()
+  "Normal: the advice is a named function so it can be removed by reference."
+  (should (fboundp 'cj/--telega-docker-image-name)))
+
+(ert-deftest test-telega-config-pin-default-is-a-digest-reference ()
+  "Normal: the shipped default pins by digest, not by a floating tag.
+A tag pin (:latest, or even a version tag upstream can re-push) still
+moves; a digest names one immutable image.
+
+Reads the defcustom's standard value rather than the live variable, so
+customizing the pin (including to nil, handing the choice back to telega)
+is not a test failure -- only changing the shipped default is."
+  (let ((default (eval (car (get 'cj/telega-docker-image 'standard-value)) t)))
+    (should (stringp default))
+    (should (string-match-p "@sha256:[0-9a-f]\\{64\\}\\'" default))))
+
+(provide 'test-telega-config--docker-pin)
+;;; test-telega-config--docker-pin.el ends here