GNU bug report logs - #46951
CC Mode 5.35.1 (C++/l); c-state-cache inconsistency

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Michael Welsh Duggan <md5i <at> md5i.com>
To: submit <at> debbugs.gnu.org
Subject: CC Mode 5.35.1 (C++/l); c-state-cache inconsistency
Date: Fri, 05 Mar 2021 16:15:20 -0500

[Message part 1 (text/plain, inline)]

Package: cc-mode

I run cc-mode with c parse state debugging turned on.  In the course of
normal usage, I found a file that reliably triggers a cache state
inconsistency.  (This is a courtesy report.  I'm not actually
encountering any bad cc-mode behavior right now.)

Reproducer:

emacs -Q
C-x C-f test.h RET
M-x c-toggle-parse-state-cache RET
M-x what-line
C-v
M-x what-line


The resulting log in *Messages*:

c-debug-parse-state enabled
Line 1
c-parse-state inconsistency at 2465: using cache: (2462 (1208 . 1674)), from scratch: (2462 (1863 . 2060)).  POINT-MIN: 1
Old state:
(setq c-state-cache '(2233 2219 2150 (1863 . 2060))  c-state-cache-good-pos 2151  c-state-nonlit-pos-cache nil  c-state-nonlit-pos-cache-limit 1  c-state-brace-pair-desert '(1 . 1208)  c-state-point-min 1  c-state-point-min-lit-type nil  c-state-point-min-lit-start nil  c-state-min-scan-pos 1  c-state-old-cpp-beg (copy-marker 1769)  c-state-old-cpp-end (copy-marker 2432)  c-parse-state-point 2244)
c-parse-state inconsistency at 2524: using cache: (2509 (1208 . 1674)), from scratch: (2509 (1863 . 2060)).  POINT-MIN: 1
Old state:
(setq c-state-cache '(2462 (1208 . 1674))  c-state-cache-good-pos 2433  c-state-nonlit-pos-cache nil  c-state-nonlit-pos-cache-limit 1  c-state-brace-pair-desert '(1 . 1208)  c-state-point-min 1  c-state-point-min-lit-type nil  c-state-point-min-lit-start nil  c-state-min-scan-pos 1  c-state-old-cpp-beg (copy-marker 2434)  c-state-old-cpp-end (copy-marker 2482)  c-parse-state-point 2465)
c-parse-state inconsistency at 2600: using cache: (2592 (1208 . 1674)), from scratch: (2592 (1863 . 2060)).  POINT-MIN: 1
Old state:
(setq c-state-cache '(2509 (1208 . 1674))  c-state-cache-good-pos 2483  c-state-nonlit-pos-cache nil  c-state-nonlit-pos-cache-limit 1  c-state-brace-pair-desert '(1 . 1208)  c-state-point-min 1  c-state-point-min-lit-type nil  c-state-point-min-lit-start nil  c-state-min-scan-pos 1  c-state-old-cpp-beg (copy-marker 2483)  c-state-old-cpp-end (copy-marker 2541)  c-parse-state-point 2524)
c-parse-state inconsistency at 2610: using cache: (2592 (1208 . 1674)), from scratch: (2592 (1863 . 2060)).  POINT-MIN: 1
Old state:
(setq c-state-cache '(2592 (1208 . 1674))  c-state-cache-good-pos 2566  c-state-nonlit-pos-cache nil  c-state-nonlit-pos-cache-limit 1  c-state-brace-pair-desert '(1 . 1208)  c-state-point-min 1  c-state-point-min-lit-type nil  c-state-point-min-lit-start nil  c-state-min-scan-pos 1  c-state-old-cpp-beg (copy-marker 2543)  c-state-old-cpp-end (copy-marker 2634)  c-parse-state-point 2600)
Line 32

[test.h (text/x-chdr, attachment)]

[Message part 3 (text/plain, inline)]

Emacs  : GNU Emacs 28.0.50 (build 2, x86_64-pc-linux-gnu, X toolkit, cairo version 1.16.0)
 of 2021-03-05
Package: CC Mode 5.35.1 (C++//l)
Buffer Style: gnu
c-emacs-features: (pps-extended-state col-0-paren posix-char-classes gen-string-delim gen-comment-delim syntax-properties 1-bit)

current state:
==============
(setq
 c-basic-offset 2
 c-comment-only-line-offset '(0 . 0)
 c-indent-comment-alist '((anchored-comment column . 0) (end-block space . 1)
			  (cpp-end-block space . 2))
 c-indent-comments-syntactically-p nil
 c-block-comment-prefix ""
 c-comment-prefix-regexp '((pike-mode . "//+!?\\|\\**") (awk-mode . "#+")
			   (other . "//+\\|\\**"))
 c-doc-comment-style '((java-mode . javadoc) (pike-mode . autodoc)
		       (c-mode . gtkdoc) (c++-mode . gtkdoc))
 c-cleanup-list '(scope-operator)
 c-hanging-braces-alist '((substatement-open before after)
			  (arglist-cont-nonempty))
 c-hanging-colons-alist nil
 c-hanging-semi&comma-criteria '(c-semi&comma-inside-parenlist)
 c-backslash-column 48
 c-backslash-max-column 72
 c-special-indent-hook '(t c-gnu-impose-minimum)
 c-label-minimum-indentation 1
 c-offsets-alist '((inexpr-class . +)
		   (inexpr-statement . +)
		   (lambda-intro-cont . +)
		   (inlambda . 0)
		   (template-args-cont c-lineup-template-args +)
		   (incomposition . +)
		   (inmodule . +)
		   (innamespace . +)
		   (inextern-lang . +)
		   (composition-close . 0)
		   (module-close . 0)
		   (namespace-close . 0)
		   (extern-lang-close . 0)
		   (composition-open . 0)
		   (module-open . 0)
		   (namespace-open . 0)
		   (extern-lang-open . 0)
		   (objc-method-call-cont
		    c-lineup-ObjC-method-call-colons
		    c-lineup-ObjC-method-call
		    +
		    )
		   (objc-method-args-cont . c-lineup-ObjC-method-args)
		   (objc-method-intro . [0])
		   (friend . 0)
		   (cpp-define-intro c-lineup-cpp-define +)
		   (cpp-macro-cont . +)
		   (cpp-macro . [0])
		   (inclass . +)
		   (stream-op . c-lineup-streamop)
		   (arglist-cont-nonempty
		    c-lineup-gcc-asm-reg
		    c-lineup-arglist
		    )
		   (arglist-cont c-lineup-gcc-asm-reg 0)
		   (comment-intro
		    c-lineup-knr-region-comment
		    c-lineup-comment
		    )
		   (catch-clause . 0)
		   (else-clause . 0)
		   (do-while-closure . 0)
		   (access-label . -)
		   (case-label . 0)
		   (substatement . +)
		   (statement-case-intro . +)
		   (statement . 0)
		   (brace-entry-open . 0)
		   (brace-list-entry . 0)
		   (brace-list-close . 0)
		   (block-close . 0)
		   (block-open . 0)
		   (inher-cont . c-lineup-multi-inher)
		   (inher-intro . +)
		   (member-init-cont . c-lineup-multi-inher)
		   (member-init-intro . +)
		   (annotation-var-cont . +)
		   (annotation-top-cont . 0)
		   (topmost-intro . 0)
		   (knr-argdecl . 0)
		   (func-decl-cont . +)
		   (inline-close . 0)
		   (class-close . 0)
		   (class-open . 0)
		   (defun-block-intro . +)
		   (defun-close . 0)
		   (defun-open . 0)
		   (c . c-lineup-C-comments)
		   (string . c-lineup-dont-change)
		   (topmost-intro-cont
		    first
		    c-lineup-topmost-intro-cont
		    c-lineup-gnu-DEFUN-intro-cont
		    )
		   (brace-list-intro
		    first
		    c-lineup-2nd-brace-entry-in-arglist
		    c-lineup-class-decl-init-+
		    +
		    )
		   (brace-list-open . +)
		   (inline-open . 0)
		   (arglist-close . c-lineup-arglist)
		   (arglist-intro . c-lineup-arglist-intro-after-paren)
		   (statement-cont . +)
		   (statement-case-open . +)
		   (label . 0)
		   (substatement-label . 0)
		   (substatement-open . +)
		   (knr-argdecl-intro . 5)
		   (statement-block-intro . +)
		   )
 c-buffer-is-cc-mode 'c++-mode
 c-tab-always-indent t
 c-syntactic-indentation t
 c-syntactic-indentation-in-macros t
 c-ignore-auto-fill '(string cpp code)
 c-auto-align-backslashes t
 c-backspace-function 'backward-delete-char-untabify
 c-delete-function 'delete-char
 c-electric-pound-behavior nil
 c-default-style '((java-mode . "java") (awk-mode . "awk") (other . "gnu"))
 c-enable-xemacs-performance-kludge-p nil
 c-old-style-variable-behavior nil
 defun-prompt-regexp nil
 tab-width 8
 comment-column 32
 parse-sexp-ignore-comments t
 parse-sexp-lookup-properties t
 auto-fill-function nil
 comment-multi-line t
 comment-start-skip "\\(?://+\\|/\\*+\\)\\s *"
 fill-prefix nil
 fill-column 70
 paragraph-start "[ 	]*\\(//+\\|\\**\\)[ 	]*$\\|^\f"
 adaptive-fill-mode t
 adaptive-fill-regexp "[ 	]*\\(//+\\|\\**\\)[ 	]*\\([ 	]*\\([-–!|#%;>*·•‣⁃◦]+[ 	]*\\)*\\)"
 )

-- 
Michael Welsh Duggan
(md5i <at> md5i.com)

Message #8 received at 46951 <at> debbugs.gnu.org (full text, mbox):

From: Alan Mackenzie <acm <at> muc.de>
To: Michael Welsh Duggan <md5i <at> md5i.com>
Cc: 46951 <at> debbugs.gnu.org
Subject: Re: bug#46951: CC Mode 5.35.1 (C++/l); c-state-cache inconsistency
Date: Sat, 6 Mar 2021 14:54:20 +0000

Hello, Michael.

On Fri, Mar 05, 2021 at 16:15:20 -0500, Michael Welsh Duggan wrote:
> Package: cc-mode

> I run cc-mode with c parse state debugging turned on.  In the course of
> normal usage, I found a file that reliably triggers a cache state
> inconsistency.  (This is a courtesy report.  I'm not actually
> encountering any bad cc-mode behavior right now.)

> Reproducer:

> emacs -Q
> C-x C-f test.h RET
> M-x c-toggle-parse-state-cache RET
> M-x what-line
> C-v
> M-x what-line


> The resulting log in *Messages*:

> c-debug-parse-state enabled
> Line 1
> c-parse-state inconsistency at 2465: using cache: (2462 (1208 . 1674)), from scratch: (2462 (1863 . 2060)).  POINT-MIN: 1
> Old state:
> (setq c-state-cache '(2233 2219 2150 (1863 . 2060))  c-state-cache-good-pos 2151  c-state-nonlit-pos-cache nil  c-state-nonlit-pos-cache-limit 1  c-state-brace-pair-desert '(1 . 1208)  c-state-point-min 1  c-state-point-min-lit-type nil  c-state-point-min-lit-start nil  c-state-min-scan-pos 1  c-state-old-cpp-beg (copy-marker 1769)  c-state-old-cpp-end (copy-marker 2432)  c-parse-state-point 2244)
> c-parse-state inconsistency at 2524: using cache: (2509 (1208 . 1674)), from scratch: (2509 (1863 . 2060)).  POINT-MIN: 1
> Old state:
> (setq c-state-cache '(2462 (1208 . 1674))  c-state-cache-good-pos 2433  c-state-nonlit-pos-cache nil  c-state-nonlit-pos-cache-limit 1  c-state-brace-pair-desert '(1 . 1208)  c-state-point-min 1  c-state-point-min-lit-type nil  c-state-point-min-lit-start nil  c-state-min-scan-pos 1  c-state-old-cpp-beg (copy-marker 2434)  c-state-old-cpp-end (copy-marker 2482)  c-parse-state-point 2465)
> c-parse-state inconsistency at 2600: using cache: (2592 (1208 . 1674)), from scratch: (2592 (1863 . 2060)).  POINT-MIN: 1
> Old state:
> (setq c-state-cache '(2509 (1208 . 1674))  c-state-cache-good-pos 2483  c-state-nonlit-pos-cache nil  c-state-nonlit-pos-cache-limit 1  c-state-brace-pair-desert '(1 . 1208)  c-state-point-min 1  c-state-point-min-lit-type nil  c-state-point-min-lit-start nil  c-state-min-scan-pos 1  c-state-old-cpp-beg (copy-marker 2483)  c-state-old-cpp-end (copy-marker 2541)  c-parse-state-point 2524)
> c-parse-state inconsistency at 2610: using cache: (2592 (1208 . 1674)), from scratch: (2592 (1863 . 2060)).  POINT-MIN: 1
> Old state:
> (setq c-state-cache '(2592 (1208 . 1674))  c-state-cache-good-pos 2566  c-state-nonlit-pos-cache nil  c-state-nonlit-pos-cache-limit 1  c-state-brace-pair-desert '(1 . 1208)  c-state-point-min 1  c-state-point-min-lit-type nil  c-state-point-min-lit-start nil  c-state-min-scan-pos 1  c-state-old-cpp-beg (copy-marker 2543)  c-state-old-cpp-end (copy-marker 2634)  c-parse-state-point 2600)
> Line 32

Indeed, yes.  Thanks for the report.

The following patch (which applies cleanly to the Emacs master branch)
should fix the bug.  I will be applying it to the master branch this
afternoon.  Please feel free to test it, but if I don't hear from you,
I'll assume the bug can be closed.

Thanks again!



diff -r d6f1f920c51c cc-engine.el
--- a/cc-engine.el	Wed Mar 03 11:44:18 2021 +0000
+++ b/cc-engine.el	Sat Mar 06 14:50:58 2021 +0000
@@ -3801,12 +3801,14 @@
 		     (point)))
 	     (bra			; Position of "{".
 	      ;; Don't start scanning in the middle of a CPP construct unless
-	      ;; it contains HERE - these constructs, in Emacs, are "commented
-	      ;; out" with category properties.
-	      (if (eq (c-get-char-property macro-start-or-from 'category)
-			'c-cpp-delimiter)
-		    macro-start-or-from
-		  from))
+	      ;; it contains HERE.
+	      (if (and (not (eq macro-start-or-from from))
+		       (< macro-start-or-from here) ; Might not be needed.
+		       (progn (goto-char macro-start-or-from)
+			      (c-end-of-macro)
+			      (>= (point) here)))
+		  from
+		macro-start-or-from))
 	     ce)			; Position of "}"
 	(or upper-lim (setq upper-lim from))
 




[ .... ]

> -- 
> Michael Welsh Duggan
> (md5i <at> md5i.com)

-- 
Alan Mackenzie (Nuremberg, Germany).

Message #11 received at 46951 <at> debbugs.gnu.org (full text, mbox):

From: Michael Welsh Duggan <mwd <at> md5i.com>
To: Alan Mackenzie <acm <at> muc.de>
Cc: 46951 <at> debbugs.gnu.org
Subject: Re: bug#46951: CC Mode 5.35.1 (C++/l); c-state-cache inconsistency
Date: Sat, 06 Mar 2021 11:07:25 -0500

Alan Mackenzie <acm <at> muc.de> writes:

> The following patch (which applies cleanly to the Emacs master branch)
> should fix the bug.  I will be applying it to the master branch this
> afternoon.  Please feel free to test it, but if I don't hear from you,
> I'll assume the bug can be closed.

I can confirm that this fixes this case.

-- 
Michael Welsh Duggan
(md5i <at> md5i.com)

Message #16 received at 46951-done <at> debbugs.gnu.org (full text, mbox):

From: Alan Mackenzie <acm <at> muc.de>
To: Michael Welsh Duggan <mwd <at> md5i.com>
Cc: 46951-done <at> debbugs.gnu.org
Subject: Re: bug#46951: CC Mode 5.35.1 (C++/l); c-state-cache inconsistency
Date: Sat, 6 Mar 2021 16:53:25 +0000

Hello, Michael.

On Sat, Mar 06, 2021 at 11:07:25 -0500, Michael Welsh Duggan wrote:
> Alan Mackenzie <acm <at> muc.de> writes:

> > The following patch (which applies cleanly to the Emacs master branch)
> > should fix the bug.  I will be applying it to the master branch this
> > afternoon.  Please feel free to test it, but if I don't hear from you,
> > I'll assume the bug can be closed.

> I can confirm that this fixes this case.

That's great, thanks very much!

I'm closing the bug with this post.

> -- 
> Michael Welsh Duggan
> (md5i <at> md5i.com)

-- 
Alan Mackenzie (Nuremberg, Germany).

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