Fix running hook variable set as buffer-local

* yasnippet.el (yas--eval-for-effect): Use `yas--safely-call-fun'
instead of `yas--safely-run-hook'.
(yas--safely-call-fun): Display the called argument (even a lambda) on
errors.
(yas--safely-run-hook): Take a hook variable instead of the hook value
itself.  Use `run-hooks' to take buffer-local values into account.
This means it’s no longer possible to warn which hook function had an
error.
(yas--check-commit-snippet): Refactor to conform to
`yas--safely-run-hooks'.
* yasnippet-tests.el (snippet-exit-hooks-bindings): New test that
checks for buffer-local, global and env hooks support.

yasnippet-tests.el

@@ -583,6 +583,38 @@ SUB"))))
          (ert-simulate-command '(yas-next-field))
          (should (eq yas--ran-exit-hook t)))))))
 
+(ert-deftest snippet-exit-hooks-bindings ()
+  "Check that `yas-after-exit-snippet-hook' is handled correctly
+in the case of a buffer-local variable and being overwritten by
+the expand-env field."
+  (defvar yas--ran-exit-hook)
+  (with-temp-buffer
+    (yas-saving-variables
+     (let ((yas--ran-exit-hook nil)
+           (yas-triggers-in-field t)
+           (yas-after-exit-snippet-hook nil))
+       (yas-with-snippet-dirs
+         '((".emacs.d/snippets"
+            ("emacs-lisp-mode"
+             ("foo" . "foobar\n")
+             ("baz" . "\
+# expand-env: ((yas-after-exit-snippet-hook (lambda () (setq yas--ran-exit-hook 'letenv))))
+# --
+foobaz\n"))))
+         (yas-reload-all)
+         (emacs-lisp-mode)
+         (yas-minor-mode +1)
+         (add-hook 'yas-after-exit-snippet-hook (lambda () (push 'global yas--ran-exit-hook)))
+         (add-hook 'yas-after-exit-snippet-hook (lambda () (push 'local yas--ran-exit-hook)) nil t)
+         (insert "baz")
+         (ert-simulate-command '(yas-expand))
+         (should (eq 'letenv yas--ran-exit-hook))
+         (insert "foo")
+         (ert-simulate-command '(yas-expand))
+         (should (eq 'global (nth 0 yas--ran-exit-hook)))
+         (should (eq 'local (nth 1 yas--ran-exit-hook))))))))
+
+
 (defvar yas--barbaz)
 (defvar yas--foobarbaz)
 

yasnippet.el

@@ -1352,7 +1352,7 @@ Returns (TEMPLATES START END). This function respects
       ((debug error) (cdr oops)))))
 
 (defun yas--eval-for-effect (form)
-  (yas--safely-run-hook (apply-partially #'eval form)))
+  (yas--safely-call-fun (apply-partially #'eval form)))
 
 (defun yas--read-lisp (string &optional nil-on-error)
   "Read STRING as a elisp expression and return it.
@@ -3336,18 +3336,19 @@ This renders the snippet as ordinary text."
   (setq yas--snippets-to-move nil))
 
 (defun yas--safely-call-fun (fun)
+  "Call FUN and catch any errors."
   (condition-case error
       (funcall fun)
     ((debug error)
-     (yas--message 2 "Error running %s: %s"
-                   (if (symbolp fun) fun "a hook")
+     (yas--message 2 "Error running %s: %s" fun
                    (error-message-string error)))))
 
 (defun yas--safely-run-hook (hook)
+  "Call HOOK's functions.
+HOOK should be a symbol, a hook variable, as in `run-hooks'."
   (let ((debug-on-error (and (not (memq yas-good-grace '(t hooks)))
                              debug-on-error)))
-    (if (functionp hook) (yas--safely-call-fun hook)
-      (mapc #'yas--safely-call-fun hook))))
+    (yas--safely-call-fun (apply-partially #'run-hooks hook))))
 
 (defun yas--check-commit-snippet ()
   "Check if point exited the currently active field of the snippet.
@@ -3355,7 +3356,9 @@ This renders the snippet as ordinary text."
 If so cleans up the whole snippet up."
   (let* ((snippets (yas-active-snippets 'all))
          (snippets-left snippets)
-         (snippet-exit-transform nil)
+         (snippet-exit-transform)
+         ;; Record the custom snippet `yas-after-exit-snippet-hook'
+         ;; set in the expand-env field.
          (snippet-exit-hook yas-after-exit-snippet-hook))
     (dolist (snippet snippets)
       (let ((active-field (yas--snippet-active-field snippet)))
@@ -3383,9 +3386,10 @@ If so cleans up the whole snippet up."
                 (t
                  nil)))))
     (unless (or (null snippets) snippets-left)
-      (if snippet-exit-transform
+      (when snippet-exit-transform
         (yas--eval-for-effect snippet-exit-transform))
-      (yas--safely-run-hook snippet-exit-hook))))
+      (let ((yas-after-exit-snippet-hook snippet-exit-hook))
+        (yas--safely-run-hook 'yas-after-exit-snippet-hook)))))
 
 ;; Apropos markers-to-points:
 ;;