installer message about /usr/local/texlive/2019 not being writable

[Zdenek Wagner]

so 23. 3. 2019 v 8:54 odesílatel Taylor, P <P.Taylor at rhul.ac.uk> napsal:
>
> Norbert Preining wrote:
> > This has been the same since about 10+ years. We check the grand-parent
> > folder (/usr/local) for writability.
>
> Zdenek Wagner wrote:
> > Before installing TL many years ago I created /usr/local/texlive as
> > root and changed its ownership to me. Thus /usr/local is not writable
> > but /usr/local/texlive is and installation works.
> I cannot see how these two statements can be reconciled.  If "we" check
> the grand-parent folder (/usr/local) for writability, and Zdeněk's
> /usr/local is not writable, then theTeX Live installer should report
> that /usr/local/texlive/2019 is not writable and refused to proceed.
>
No. The installer needs to create /usr/local/texlive/2019. Although
there is a command for creating it together with the parents, it is
actually done step by step. /usr/local already exists. The first step
is creation of /usr/local/texlive. If /usr/local is not writable, it
fails. If /usr/local/texlive already exists, the installer creates
/usr/loca/ltexlive/2019, which means that only /usr/local/texlive has
to be writable. If it is, then /usr/local/texlive/2019 will also be
writable. You can change ownership and permissions in a similar way
even on Windows unless you have a home edition. Windows even offer to
set a directory writable but not readable.

> Norbert Preining also wrote:
> > [JFBU wrote]
> >> install-tl warned me about /usr/local/texlive/2019 not being writable
> >> but in fact, of course, there wasn't even /usr/local/texlive to start with
> > This has been the same since about 10+ years. We check the grand-parent
> > folder (/usr/local) for writability.
> >
> > The message is correct, it is not writable and cannot be created.
> If, as in JFBU's case, /usr/local/texlive/2019 does not exist, then by
> definition it is both writable and non-writable, since the empty set has
> all properties.  Thus the message is only partially correct, and is most
> certainly confusing.  "Does not exist and cannot be created" would be
> the correct diagnostic in these circumstances,
>
> Philip Taylor
>