* bug#58066: pretty-print will make data modified by set-cdr! to random value @ 2022-09-24 10:01 slbtty 2022-09-25 10:16 ` Jean Abou Samra 2023-07-19 22:17 ` Jean Abou Samra 0 siblings, 2 replies; 3+ messages in thread From: slbtty @ 2022-09-24 10:01 UTC (permalink / raw) To: 58066 GNU Guile 3.0.8 Using `guile3 < file.scm` to run the code below will makes the result of tp unpredictable (pointing to very random things) (use-modules (ice-9 pretty-print)) (define tl '(1 2)) (define tp (cdr tl)) (set-cdr! tp (cons 3 '())) (pretty-print tl) (pretty-print tp) --- However, if i use plain old (display tp), the code will out put expected valve (1 2 3) (3) (define tl '(1 2)) (define tp (cdr tl)) (set-cdr! tp (cons 3 '())) (display tl) (newline) (display tp) (newline) --- Context: I am using guile3's repl and whenever i access a variable's by typing its name after (set-cdr!), the result will goes wild. ^ permalink raw reply [flat|nested] 3+ messages in thread
* bug#58066: pretty-print will make data modified by set-cdr! to random value 2022-09-24 10:01 bug#58066: pretty-print will make data modified by set-cdr! to random value slbtty @ 2022-09-25 10:16 ` Jean Abou Samra 2023-07-19 22:17 ` Jean Abou Samra 1 sibling, 0 replies; 3+ messages in thread From: Jean Abou Samra @ 2022-09-25 10:16 UTC (permalink / raw) To: slbtty, 58066 Le 24/09/2022 à 12:01, slbtty a écrit : > GNU Guile 3.0.8 > > Using `guile3 < file.scm` to run the code below will makes the result > of tp unpredictable (pointing to very random things) > > (use-modules (ice-9 pretty-print)) > (define tl '(1 2)) > (define tp (cdr tl)) > (set-cdr! tp (cons 3 '())) > (pretty-print tl) > (pretty-print tp) > --- > > However, if i use plain old (display tp), the code will out put > expected valve (1 2 3) (3) > (define tl '(1 2)) > (define tp (cdr tl)) > (set-cdr! tp (cons 3 '())) > (display tl) (newline) > (display tp) (newline) > > --- > > Context: > > I am using guile3's repl and whenever i access a variable's by typing > its name after (set-cdr!), the result will goes wild. Interesting. It looks like scm_is_mutable_pair is broken? It's defined (in pairs.h) as static inline int scm_is_mutable_pair (SCM x) { /* Guile embeds literal pairs into compiled object files. It's not valid Scheme to mutate literal values. Two practical reasons to enforce this restriction are to allow literals to share share structure (pairs) with other literals in the compilation unit, and to allow literals containing immediates to be allocated in the read-only, shareable section of the file. Attempting to mutate a pair in the read-only section would cause a segmentation fault, so to avoid that, we really do need to enforce the restriction. */ return scm_is_pair (x) && GC_is_heap_ptr (SCM2PTR (x)); } I don't know why that breaks or how to fix it, though. As you can read from the comment, this code is actually invalid Scheme, since it mutates literal data. However, it is true that Guile should raise an error for this, not segfault (which is what it does for me) or start printing random things. If you define tl as (list 1 2 3) instead of '(1 2 3), everything will be fine. ^ permalink raw reply [flat|nested] 3+ messages in thread
* bug#58066: pretty-print will make data modified by set-cdr! to random value 2022-09-24 10:01 bug#58066: pretty-print will make data modified by set-cdr! to random value slbtty 2022-09-25 10:16 ` Jean Abou Samra @ 2023-07-19 22:17 ` Jean Abou Samra 1 sibling, 0 replies; 3+ messages in thread From: Jean Abou Samra @ 2023-07-19 22:17 UTC (permalink / raw) To: 58066-done [-- Attachment #1.1: Type: text/plain, Size: 86 bytes --] Closing this as a duplicate of https://debbugs.gnu.org/cgi/bugreport.cgi?bug=16060 [-- Attachment #1.2: Type: text/html, Size: 469 bytes --] [-- Attachment #2: This is a digitally signed message part --] [-- Type: application/pgp-signature, Size: 228 bytes --] ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-07-19 22:17 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-09-24 10:01 bug#58066: pretty-print will make data modified by set-cdr! to random value slbtty 2022-09-25 10:16 ` Jean Abou Samra 2023-07-19 22:17 ` Jean Abou Samra
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