bug#39529: closed (28.0.50; Metahelp does not contain help text)

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Your message dated Sat, 15 Feb 2020 15:25:44 -0800
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and subject line Re: bug#39529: 28.0.50; Metahelp does not contain help text
has caused the debbugs.gnu.org bug report #39529,
regarding 28.0.50; Metahelp does not contain help text
to be marked as done.

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39529: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=39529
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> --- Begin Message ---
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> Subject: 
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> 28.0.50; Metahelp does not contain help text
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> Date: 
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> Sun, 09 Feb 2020 20:06:40 +0100
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> On Emacs 28.0.50 (5e7bead8ea), typing C-h C-h will display the
> *Metahelp* buffer, but instead of containing the usual help information,
> it will contain just the following:
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> Automatically break line at a previous space, in insertion of text.
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> (which appears to be the document string for `auto-fill-function' in
> simple.el).
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--- Begin Message --- Subject: Re: bug#39529: 28.0.50; Metahelp does not contain help text Date: Sat, 15 Feb 2020 15:25:44 -0800 User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1

On 2/9/20 11:34 AM, Eli Zaretskii wrote:

I suspect the sxhash changes on Jan 7.  This problem started happening
in that day's build.

Right you are. The problem was Emacs was using a hash table to unify identical Lisp compiled objects when purecopying them, even though their doc strings were not set up yet (and so were 0 placeholders that always compared equal). Formerly this bug was masked because sxhash simply returned the objects' hashed addresses, but the January 7 changes unveiled the bug. I install the attached patch to fix the problem.

0001-Fix-C-h-C-h-bug-due-to-mutating-a-hash-key.patch
Description: Text Data

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