Re: [PATCH v2 1/1] Increase default HISTSIZE to 1000

[Felipe Contreras <felipe.contreras@gmail.com>]

On Tue, Sep 6, 2022 at 3:15 PM Mikael Magnusson <mikachu@gmail.com> wrote:
> On 9/6/22, Felipe Contreras <felipe.contreras@gmail.com> wrote:

> > If the default is sensible then it's not necessary for the user to
> > change it.
> >
> > Moreover, the FAQ is wrong: it says it's necessary to set HISTSIZE for
> > the history to saved, but it isn't. HISTSIZE by default is 30 and that's
> > enough to save the history, although not very useful. Therefore only
> > *two* variables need to be set.
> >
> > This is even more clear after we remove HISTSIZE from the example, but
> > then the text "The simplest possibility is to set it to the same as
> > tt($HISTSIZE) as above" becomes problematic as the value of HISTSIZE is
> > not readily available.
> >
> > The user doesn't need to know the value of HISTSIZE though, she can
> > simply use $HISTSIZE instead.
> >
> > This has the advantage that if HISTSIZE is increased again in the future
> > (as it probably should because most modern computers can easily afford
> > orders of magnitude more), nobody needs to worry about SAVEHIST (neither
> > in the FAQ, zsh-newuser-install, or existing zshrc files).
> >
> > Also, semantically makes more sense and carries less cognitive load.
> >
> > Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
> > ---
> >  Etc/FAQ.yo                            | 17 +++++++----------
> >  Functions/Newuser/zsh-newuser-install |  3 +--
> >  StartupFiles/zshrc                    |  2 +-
> >  configure.ac                          |  2 +-
> >  4 files changed, 10 insertions(+), 14 deletions(-)
> >
> > diff --git a/Etc/FAQ.yo b/Etc/FAQ.yo
> > index 8c795685a..4c058c363 100644
> > --- a/Etc/FAQ.yo
> > +++ b/Etc/FAQ.yo
> > @@ -1626,19 +1626,16 @@ work?)
> >  sect(Why is my history not being saved?)
> >  label(321)
> >
> > -  In zsh, you need to set three variables to make sure your history is
> > +  In zsh, you need to set two variables to make sure your history is
> >    written out when the shell exits.  For example,
> >    verb(
> > -    HISTSIZE=200
> >      HISTFILE=~/.zsh_history
> > -    SAVEHIST=200
> > -  )
> > -  tt($HISTSIZE) tells the shell how many lines to keep internally,
> > -  tt($HISTFILE) tells it where to write the history, and tt($SAVEHIST),
> > -  the easiest one to forget, tells it how many to write out.  The
> > -  simplest possibility is to set it to the same as tt($HISTSIZE) as
> > -  above.  There are also various options affecting history; see the
> > -  manual.
> > +    SAVEHIST=$HISTSIZE
> > +  )
> > +  tt($HISTFILE) tells the shell where to write the history, and
> > tt($SAVEHIST)
> > +  tells it how many lines to write out.  The simplest possibility is to set
> > it
> > +  to the same as tt($HISTSIZE) as above.  There are also various options
> > +  affecting history; see the manual.
>
> NAK on the above hunk from me, making the FAQ less informative is not a goal.

The goal of the FAQ is to answer common questions, and the goal of
this entry is to answer the question "Why is my history not being
saved?", not inform the user about history. That's already done in the
user's guide Setting up history [1], and in the manual's roadmap
Interactive Use [2]. If you want to inform the user about history, a
link should be provided to either of those, not attempt to repeat the
same information except in a poorer way.

To answer the question at hand "Why is my history not being saved?"
it's *not necessary* to explain HISTSIZE (yet again), and it's not
desirable to answer something the user did not ask.

> >  sect(How do I get a variable's value to be evaluated as another variable?)
> >
> > diff --git a/Functions/Newuser/zsh-newuser-install
> > b/Functions/Newuser/zsh-newuser-install
> > index 9e911d07c..46b1639c5 100644
> > --- a/Functions/Newuser/zsh-newuser-install
> > +++ b/Functions/Newuser/zsh-newuser-install
> > @@ -790,9 +790,8 @@ ${(F)unparsed}
> >
> >  __zni_history_config() {
> >    __zni_apply_defaults -p \
> > -    HISTSIZE 1000 "Number of lines of history kept within the shell." \
> >      HISTFILE $zdmsg/.histfile "File where history is saved." \
> > -    SAVEHIST 1000 "Number of lines of history to save to \$HISTFILE."
> > +    SAVEHIST \$HISTSIZE "Number of lines of history to save to
> > \$HISTFILE."
> >
> >    if __zni_display_and_edit "History configuration"; then
> >      install_state[history]="Unsaved changes"
>
> Ditto here for the same reason.

The reason "making the FAQ less informative is not a goal" doesn't
apply here. The purpose of the zsh-newuser-install script is not to
provide the user with information, again, that is already done in the
user's guide and the manual. Neither is it to inform the user of all
the history options in the manual [3] that the user might want to set,
like EXTENDED_HISTORY, HIST_IGNORE_SPACE, INC_APPEND_HISTORY, or
SHARE_HISTORY.

The purpose of the script as it's clearly stated when you start it is
"help you with a few settings that should make your use of the shell
easier", not inform the user of all the settings, or even typical
settings.

[1] https://zsh.sourceforge.io/Guide/zshguide02.html#l17
[2] https://zsh.sourceforge.io/Doc/Release/Roadmap.html#Interactive-Use
[3] https://zsh.sourceforge.io/Doc/Release/Options.html#Description-of-Options

-- 
Felipe Contreras