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| author | Stefan Monnier <monnier@iro.umontreal.ca> | 2019-02-12 16:33:23 -0500 |
|---|---|---|
| committer | Stefan Monnier <monnier@iro.umontreal.ca> | 2019-02-12 16:33:23 -0500 |
| commit | 3f4b8e9a299f88a8ea11c0ea6a281a34852e541a (patch) | |
| tree | b8e7c1a11db4e76a9ec156b84a41b11288a763c8 | |
| parent | b384996e86cb5172dd0d5283f178de7f2654a2f4 (diff) | |
| download | emacs-3f4b8e9a299f88a8ea11c0ea6a281a34852e541a.tar.gz emacs-3f4b8e9a299f88a8ea11c0ea6a281a34852e541a.tar.bz2 emacs-3f4b8e9a299f88a8ea11c0ea6a281a34852e541a.zip | |
* src/data.c (Fmake_local_variable): Fix bug#34318
Revert part of ed962f2b8a.
* test/src/data-tests.el (data-tests-make-local-forwarded-var):
Add corresponding test.
| -rw-r--r-- | src/data.c | 10 | ||||
| -rw-r--r-- | test/src/data-tests.el | 18 |
2 files changed, 28 insertions, 0 deletions
diff --git a/src/data.c b/src/data.c index 571114802a1..ed6dedbe243 100644 --- a/src/data.c +++ b/src/data.c @@ -1954,6 +1954,16 @@ Instead, use `add-hook' and specify t for the LOCAL argument. */) (current_buffer, Fcons (Fcons (variable, XCDR (blv->defcell)), BVAR (current_buffer, local_var_alist))); + + /* If the symbol forwards into a C variable, then load the binding + for this buffer now, to preserve the invariant that forwarded + variables must always hold the value corresponding to the + current buffer (they are swapped eagerly). + Otherwise, if C code modifies the variable before we load the + binding in, then that new value would clobber the default binding + the next time we unload it. See bug#34318. */ + if (blv->fwd) + swap_in_symval_forwarding (sym, blv); } return variable; diff --git a/test/src/data-tests.el b/test/src/data-tests.el index 0069ee84fe1..f3b4262de4b 100644 --- a/test/src/data-tests.el +++ b/test/src/data-tests.el @@ -508,4 +508,22 @@ comparing the subr with a much slower lisp implementation." (bound-and-true-p data-tests-foo2) (bound-and-true-p data-tests-foo3))))))) +(ert-deftest data-tests-make-local-forwarded-var () ;bug#34318 + ;; Boy, this bug is tricky to trigger. You need to: + ;; - call make-local-variable on a forwarded var (i.e. one that + ;; has a corresponding C var linked via DEFVAR_(LISP|INT|BOOL)) + ;; - cause the C code to modify this variable from the C side of the + ;; forwarding, but this needs to happen before the var is accessed + ;; from the Lisp side and before we switch to another buffer. + ;; The trigger in bug#34318 doesn't exist any more because the C code has + ;; changes. Instead I found the trigger below. + (with-temp-buffer + (setq last-coding-system-used 'bug34318) + (make-local-variable 'last-coding-system-used) + ;; This should set last-coding-system-used to `no-conversion'. + (decode-coding-string "hello" nil) + (should (equal (list last-coding-system-used + (default-value 'last-coding-system-used)) + '(no-conversion bug34318))))) + ;;; data-tests.el ends here |