bug#36068: 27.0.50; Warning: unescaped character literals `?)' detected, `?\)' expected!

bug#36068: 27.0.50; Warning: unescaped character literals `?)' detected, `?\)' expected!

[Michael Heerdegen]

Hello,

Sometimes, out of nowhere, when I byte compile my init file (with my
config loaded of course), I get hundreds (!) of warnings

.gnu-emacs.el:22:1:Warning: unescaped character literals `?)' detected, `?\)'
    expected!

Dunno if it happens when there is a syntax error in the file, or just
Heisenbug like.  When this has happened once, I cannot get back to a
normal compilation, compiling any Elisp file gives me the above
warnings.  I have to restart Emacs.  Then everything is good.

I have still open such an ill session, maybe it can help with the
diagnosis?


TIA,

Michael.


In GNU Emacs 27.0.50 (build 19, x86_64-pc-linux-gnu, GTK+ Version 3.24.5)
 of 2019-06-03 built on drachen
Repository revision: ae7e0657b20037eb386aa21a35f05bcb4c283611
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12003000
System Description: Debian GNU/Linux 10 (buster)

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bug#36068: 27.0.50; Warning: unescaped character literals `?)' detected, `?\)' expected!

[Noam Postavsky]

Michael Heerdegen <michael_heerdegen@web.de> writes:

> Sometimes, out of nowhere, when I byte compile my init file (with my
> config loaded of course), I get hundreds (!) of warnings
>
> .gnu-emacs.el:22:1:Warning: unescaped character literals `?)' detected, `?\)'
>     expected!
>
> Dunno if it happens when there is a syntax error in the file, or just
> Heisenbug like.  When this has happened once, I cannot get back to a
> normal compilation, compiling any Elisp file gives me the above
> warnings.  I have to restart Emacs.  Then everything is good.
>
> I have still open such an ill session, maybe it can help with the
> diagnosis?

Hmm, is lread--unescaped-character-literals non-nil?  It looks like the
variable can only get cleared due to the let-binding in load, so if it
somehow got set outside of that, then you would see continual warnings
from it.

bug#36068: 27.0.50; Warning: unescaped character literals `?)' detected, `?\)' expected!

[Michael Heerdegen]

Noam Postavsky <npostavs@gmail.com> writes:

> Hmm, is lread--unescaped-character-literals non-nil?  It looks like
> the variable can only get cleared due to the let-binding in load, so
> if it somehow got set outside of that, then you would see continual
> warnings from it.

Yes, its value is (41).

Michael.

bug#36068: 27.0.50; Warning: unescaped character literals `?)' detected, `?\)' expected!

[npostavs]

tags 36068 + confirmed
quit

Michael Heerdegen <michael_heerdegen@web.de> writes:

> Noam Postavsky <npostavs@gmail.com> writes:
>
>> Hmm, is lread--unescaped-character-literals non-nil?  It looks like
>> the variable can only get cleared due to the let-binding in load, so
>> if it somehow got set outside of that, then you would see continual
>> warnings from it.
>
> Yes, its value is (41).

Ah, I think the problem can be triggered any time you `read' an unescaped
literal outside of `load'.  E.g., from emacs -Q:

    M-: (read "?)") RET

or even just

    M-: ?) RET

Now any byte-compilation will report unescaped `?)'.  You can

    (setq lread--unescaped-character-literals nil)

to stop it.

bug#36068: 27.0.50; Warning: unescaped character literals `?)' detected, `?\)' expected!

[Michael Heerdegen]

npostavs@gmail.com writes:

> Ah, I think the problem can be triggered any time you `read' an unescaped
> literal outside of `load'.  E.g., from emacs -Q:
>
>     M-: (read "?)") RET
>
> or even just
>
>     M-: ?) RET
>
> Now any byte-compilation will report unescaped `?)'.  You can
>
>     (setq lread--unescaped-character-literals nil)
>
> to stop it.

I can confirm all of that.

I use `read' quite often through el-search, also through an experimental
el-search-hi-lock mode, so that might explain why I might see the
problem more often than others.

Michael.

bug#36068: 27.0.50; Warning: unescaped character literals `?)' detected, `?\)' expected!

[Eli Zaretskii]

> From: npostavs@gmail.com
> Date: Mon, 03 Jun 2019 09:50:47 -0400
> Cc: 36068@debbugs.gnu.org, Noam Postavsky <npostavs@gmail.com>
> 
> Ah, I think the problem can be triggered any time you `read' an unescaped
> literal outside of `load'.  E.g., from emacs -Q:
> 
>     M-: (read "?)") RET
> 
> or even just
> 
>     M-: ?) RET
> 
> Now any byte-compilation will report unescaped `?)'.

Maybe we should forcefully set it to nil at top level?

bug#36068: 27.0.50; Warning: unescaped character literals `?)' detected, `?\)' expected!

[Andreas Schwab]

On Jun 03 2019, Eli Zaretskii <eliz@gnu.org> wrote:

>> From: npostavs@gmail.com
>> Date: Mon, 03 Jun 2019 09:50:47 -0400
>> Cc: 36068@debbugs.gnu.org, Noam Postavsky <npostavs@gmail.com>
>> 
>> Ah, I think the problem can be triggered any time you `read' an unescaped
>> literal outside of `load'.  E.g., from emacs -Q:
>> 
>>     M-: (read "?)") RET
>> 
>> or even just
>> 
>>     M-: ?) RET
>> 
>> Now any byte-compilation will report unescaped `?)'.
>
> Maybe we should forcefully set it to nil at top level?

But how can load_warn_unescaped_character_literals be called while
lread--unescaped-character-literals is not let-bound?

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

bug#36068: 27.0.50; Warning: unescaped character literals `?)' detected, `?\)' expected!

[npostavs]

Andreas Schwab <schwab@linux-m68k.org> writes:

> On Jun 03 2019, Eli Zaretskii <eliz@gnu.org> wrote:
>
>>> From: npostavs@gmail.com

>>> Ah, I think the problem can be triggered any time you `read' an unescaped
>>> literal outside of `load'.  E.g., from emacs -Q:

>>>     M-: ?) RET
>>> 
>>> Now any byte-compilation will report unescaped `?)'.
>>
>> Maybe we should forcefully set it to nil at top level?
>
> But how can load_warn_unescaped_character_literals be called while
> lread--unescaped-character-literals is not let-bound?

It's not.  byte-run--unescaped-character-literals-warning is called from
the byte compiler.  So maybe just let-binding
lread--unescaped-character-literals in byte-compile-from-buffer should
be enough.

bug#36068: 27.0.50; Warning: unescaped character literals `?)' detected, `?\)' expected!

[Andreas Schwab]

On Jun 03 2019, npostavs@gmail.com wrote:

> tags 36068 + confirmed
> quit
>
> Michael Heerdegen <michael_heerdegen@web.de> writes:
>
>> Noam Postavsky <npostavs@gmail.com> writes:
>>
>>> Hmm, is lread--unescaped-character-literals non-nil?  It looks like
>>> the variable can only get cleared due to the let-binding in load, so
>>> if it somehow got set outside of that, then you would see continual
>>> warnings from it.
>>
>> Yes, its value is (41).
>
> Ah, I think the problem can be triggered any time you `read' an unescaped
> literal outside of `load'.  E.g., from emacs -Q:
>
>     M-: (read "?)") RET
>
> or even just
>
>     M-: ?) RET

Even byte-compiling a file containing such an unescaped literal sets
lread--unescaped-character-literals in the global scope.  I think this
is where the real bug is.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

bug#36068: 27.0.50; Warning: unescaped character literals `?)' detected, `?\)' expected!

[Noam Postavsky]

[-- Attachment #1: Type: text/plain, Size: 390 bytes --]

tags 36068 + patch
quit

>> Ah, I think the problem can be triggered any time you `read' an unescaped
>> literal outside of `load'.  E.g., from emacs -Q:
>>
>>     M-: (read "?)") RET
>
> Even byte-compiling a file containing such an unescaped literal sets
> lread--unescaped-character-literals in the global scope.  I think this
> is where the real bug is.

Yes, agreed.  Here's a patch.


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: patch --]
[-- Type: text/x-diff, Size: 3965 bytes --]

From ffa9c9e17bd6724107b6c3b5c49221b58d7c92ab Mon Sep 17 00:00:00 2001
From: Noam Postavsky <npostavs@gmail.com>
Date: Tue, 4 Jun 2019 21:26:06 -0400
Subject: [PATCH] Don't keep warning about unescaped literals (Bug#36068)

* lisp/emacs-lisp/bytecomp.el (byte-compile-from-buffer): Restore lost
let-binding of lread--unescaped-character-literals, so that unescaped
literals warning will only apply to the form just read.
* test/lisp/emacs-lisp/bytecomp-tests.el
(bytecomp-tests--unescaped-char-literals): Expand test to check that
we don't keep warning about old unescaped literals.
---
 lisp/emacs-lisp/bytecomp.el            |  5 +++--
 test/lisp/emacs-lisp/bytecomp-tests.el | 32 +++++++++++++++++++-------------
 2 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/lisp/emacs-lisp/bytecomp.el b/lisp/emacs-lisp/bytecomp.el
index dfbda8d43e..f8a5c264ab 100644
--- a/lisp/emacs-lisp/bytecomp.el
+++ b/lisp/emacs-lisp/bytecomp.el
@@ -2091,8 +2091,9 @@ (defun byte-compile-from-buffer (inbuffer)
 		 (not (eobp)))
 	  (setq byte-compile-read-position (point)
 		byte-compile-last-position byte-compile-read-position)
-	  (let ((form (read inbuffer))
-                (warning (byte-run--unescaped-character-literals-warning)))
+          (let* ((lread--unescaped-character-literals nil)
+                 (form (read inbuffer))
+                 (warning (byte-run--unescaped-character-literals-warning)))
             (when warning (byte-compile-warn "%s" warning))
 	    (byte-compile-toplevel-file-form form)))
 	;; Compile pending forms at end of file.
diff --git a/test/lisp/emacs-lisp/bytecomp-tests.el b/test/lisp/emacs-lisp/bytecomp-tests.el
index f45c9209c1..83162d250f 100644
--- a/test/lisp/emacs-lisp/bytecomp-tests.el
+++ b/test/lisp/emacs-lisp/bytecomp-tests.el
@@ -559,19 +559,25 @@ (ert-deftest bytecomp-tests--unescaped-char-literals ()
   "Check that byte compiling warns about unescaped character
 literals (Bug#20852)."
   (should (boundp 'lread--unescaped-character-literals))
-  (bytecomp-tests--with-temp-file source
-    (write-region "(list ?) ?( ?; ?\" ?[ ?])" nil source)
-    (bytecomp-tests--with-temp-file destination
-      (let* ((byte-compile-dest-file-function (lambda (_) destination))
-            (byte-compile-error-on-warn t)
-            (byte-compile-debug t)
-            (err (should-error (byte-compile-file source))))
-        (should (equal (cdr err)
-                       (list (concat "unescaped character literals "
-                                     "`?\"', `?(', `?)', `?;', `?[', `?]' "
-                                     "detected, "
-                                     "`?\\\"', `?\\(', `?\\)', `?\\;', `?\\[', "
-                                     "`?\\]' expected!"))))))))
+  (let ((byte-compile-error-on-warn t)
+        (byte-compile-debug t))
+    (bytecomp-tests--with-temp-file source
+      (write-region "(list ?) ?( ?; ?\" ?[ ?])" nil source)
+      (bytecomp-tests--with-temp-file destination
+        (let* ((byte-compile-dest-file-function (lambda (_) destination))
+               (err (should-error (byte-compile-file source))))
+          (should (equal (cdr err)
+                         `(,(concat "unescaped character literals "
+                                    "`?\"', `?(', `?)', `?;', `?[', `?]' "
+                                    "detected, "
+                                    "`?\\\"', `?\\(', `?\\)', `?\\;', `?\\[', "
+                                    "`?\\]' expected!")))))))
+    ;; But don't warn in subsequent compilations (Bug#36068).
+    (bytecomp-tests--with-temp-file source
+      (write-region "(list 1 2 3)" nil source)
+      (bytecomp-tests--with-temp-file destination
+        (let ((byte-compile-dest-file-function (lambda (_) destination)))
+          (should (byte-compile-file source)))))))
 
 (ert-deftest bytecomp-tests--old-style-backquotes ()
   "Check that byte compiling warns about old-style backquotes."
-- 
2.11.0

bug#36068: 27.0.50; Warning: unescaped character literals `?)' detected, `?\)' expected!

[Noam Postavsky]

tags 36068 fixed
close 36068 
quit

>> Even byte-compiling a file containing such an unescaped literal sets
>> lread--unescaped-character-literals in the global scope.  I think this
>> is where the real bug is.
>
> Yes, agreed.  Here's a patch.

Pushed to master.

0026d0bf9f 2019-06-10T18:27:22-04:00 "Don't keep warning about unescaped literals (Bug#36068)"
https://git.savannah.gnu.org/cgit/emacs.git/commit/?id=0026d0bf9f4e4e0247de9c1eb885507608378266