branch: externals/persist
commit dab814ab0ffab1c08f48cc088fb93476d6908152
Author: Joseph Turner <[email protected]>
Commit: Philip Kaludercic <[email protected]>
Fix persist-default prop being set to current value
Previously, if a persist-defvar form was evaluated after the variable
was bound, the default value would be set to the whatever the current
value was instead of INITVALUE. This sometimes led to a data loss
bug, since persist-save deletes when the current value is
persist-equal to the default value. Resolves bug#75779.
---
persist.el | 17 +++++++++++------
test/persist-tests.el | 6 ++++++
2 files changed, 17 insertions(+), 6 deletions(-)
diff --git a/persist.el b/persist.el
index 3260df0964..c6c708efc6 100644
--- a/persist.el
+++ b/persist.el
@@ -66,18 +66,20 @@ variable is not set to the value.")
(or (get symbol 'persist-location)
persist--directory-location)))
-(defun persist--defvar-1 (symbol location)
+(defun persist--defvar-1 (symbol location initvalue)
"Set symbol up for persistence."
(when location
(persist-location symbol location))
- (persist-symbol symbol (symbol-value symbol))
+ (persist-symbol symbol initvalue)
(persist-load symbol))
(defmacro persist-defvar (symbol initvalue docstring &optional location)
"Define SYMBOL as a persistent variable and return SYMBOL.
This form is nearly equivalent to `defvar', except that the
-variable persists between Emacs sessions.
+variable persists between Emacs sessions. When this form is
+evaluated, the variable's default value is always set to
+INITVALUE.
It does not support the optional parameters. Both INITVALUE and
DOCSTRING need to be given."
@@ -95,9 +97,12 @@ DOCSTRING need to be given."
;; Define inside progn so the byte compiler sees defvar
`(progn
(defvar ,symbol ,initvalue ,docstring)
- ;; Access initvalue through its symbol because the defvar form
- ;; has to stay at first level within a progn
- (persist--defvar-1 ',symbol ,location)
+ ;; `defvar' must stay at top level within `progn'. Pass init
+ ;; value to `persist--defvar-1' since the `defvar' form may not
+ ;; set the symbol's value and we don't want to set the
+ ;; persist-default property to the current value of the symbol.
+ ;; See bug#75779 for details.
+ (persist--defvar-1 ',symbol ,location ,initvalue)
',symbol))
(defun persist-location (symbol directory)
diff --git a/test/persist-tests.el b/test/persist-tests.el
index 6bf2ed3708..2c452b7d38 100644
--- a/test/persist-tests.el
+++ b/test/persist-tests.el
@@ -108,6 +108,12 @@
(should (= 20
(persist-default 'test-persist-variable)))))
+(ert-deftest test-persist-default-set-to-initvalue ()
+ (persist-defvar test-persist-variable-default 'INIT "Docstring.")
+ (setq test-persist-variable-default 'CHANGED)
+ (persist-defvar test-persist-variable-default 'INIT "Docstring.")
+ (should (equal 'INIT (persist-default 'test-persist-variable-default))))
+
(ert-deftest test-persist-location ()
(unwind-protect
(let ((sym (cl-gensym)))
