Re: [PATCH] Fix persist-reset

[Joseph Turner <joseph@ushin.org>]

[-- Attachment #1: Type: text/plain, Size: 581 bytes --]

Adam Porter <adam@alphapapa.net> writes:

> Hi Joseph,
>
> On 6/12/24 20:49, Joseph Turner wrote:
>> Previously, persist-reset set the value of SYM to its default without
>> copying it, which caused subsequent modifications to the value of SYM
>> to erroneously modify the default value.
>
> The only suggestion I can think of would be, in the test, to perhaps
> bind to a variable the initial hash table set as the default value, so
> that you could also compare against that with EQ to ensure that the
> original table is not being reused.

Good idea!  Please see new patchset.


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-Copy-default-when-resetting-with-persist-reset.patch --]
[-- Type: text/x-diff, Size: 1886 bytes --]

From 39b1a0a1d1ae25130a270a115ae8241af4ed6d75 Mon Sep 17 00:00:00 2001
From: Joseph Turner <joseph@breatheoutbreathe.in>
Date: Wed, 12 Jun 2024 18:45:32 -0700
Subject: [PATCH 1/2] Copy default when resetting with persist-reset

Previously, persist-reset set the value of SYM to its default without
copying it, which caused subsequent modifications to the value of SYM
to erroneously modify the default value.

Co-authored-by: Adam Porter <adam@alphapapa.net>
---
 persist.el | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/persist.el b/persist.el
index 6cc94b4db3..df7f3836c5 100644
--- a/persist.el
+++ b/persist.el
@@ -122,9 +122,7 @@ (defun persist-symbol (symbol &optional initvalue)
   (let ((initvalue (or initvalue (symbol-value symbol))))
     (add-to-list 'persist--symbols symbol)
     (put symbol 'persist t)
-    (if (hash-table-p initvalue)
-        (put symbol 'persist-default (copy-hash-table initvalue))
-      (put symbol 'persist-default (persist-copy-tree initvalue t)))))
+    (put symbol 'persist-default (persist-copy initvalue))))
 
 (defun persist--persistant-p (symbol)
   "Return non-nil if SYMBOL is a persistent variable."
@@ -164,8 +162,8 @@ (defun persist-default (symbol)
   (get symbol 'persist-default))
 
 (defun persist-reset (symbol)
-  "Reset the value of SYMBOL to the default."
-  (set symbol (persist-default symbol)))
+  "Set the value of SYMBOL to a copy of the default."
+  (set symbol (persist-copy (persist-default symbol))))
 
 (defun persist-load (symbol)
   "Load the saved value of SYMBOL."
@@ -241,5 +239,11 @@ (defun persist-copy-tree (tree &optional vectors-and-records)
 	  tree)
       tree)))
 
+(defun persist-copy (obj)
+  "Return copy of OBJ."
+  (if (hash-table-p obj)
+      (copy-hash-table obj)
+    (persist-copy-tree obj t)))
+
 (provide 'persist)
 ;;; persist.el ends here
-- 
2.41.0


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #3: 0002-Test-persist-reset.patch --]
[-- Type: text/x-diff, Size: 1564 bytes --]

From b30f854d149d7cbe550716d3cfdbeb170a6ca1ab Mon Sep 17 00:00:00 2001
From: Joseph Turner <joseph@breatheoutbreathe.in>
Date: Wed, 12 Jun 2024 18:45:36 -0700
Subject: [PATCH 2/2] Test persist-reset

Co-authored-by: Adam Porter <adam@alphapapa.net>
---
 test/persist-tests.el | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/test/persist-tests.el b/test/persist-tests.el
index 62d8501493..4439fa3e07 100644
--- a/test/persist-tests.el
+++ b/test/persist-tests.el
@@ -134,3 +134,20 @@ (ert-deftest test-persist-location ()
         (should-error
          (persist-save 'fred)))
     (delete-directory "./persist-defined-location" t)))
+
+(ert-deftest test-persist-reset ()
+  "Symbol should be reset to a copy of the default."
+  (let ((initial-value (make-hash-table)))
+    (with-local-temp-persist
+     (persist-defvar persist--test-reset-variable initial-value "docstring")
+     (should-not (eq persist--test-reset-variable
+                     (persist-default 'persist--test-reset-variable)))
+     (should-not (eq persist--test-reset-variable initial-value))
+     (should-not (eq initial-value
+                     (persist-default 'persist--test-reset-variable)))
+     (persist-reset 'persist--test-reset-variable)
+     (should-not (eq persist--test-reset-variable
+                     (persist-default 'persist--test-reset-variable)))
+     (should-not (eq persist--test-reset-variable initial-value))
+     (should-not (eq initial-value
+                     (persist-default 'persist--test-reset-variable))))))
-- 
2.41.0