Upgrade failure and corrupted installation ?

[Yann Salmon]

> You added the --list, don't do that.

It still says no updates available.


> If you do that it might look
> like you have packages installed but the actual files are missing.

Since the tlpdb lists the files of the packages, I could check which 
packages are missing files (and should therefore be reinstalled) ?

> So I am not sure if it is worth the pain to split.
> 
> OTOH, doing some more safety measures if possible, I am more than open
> to suggestions.

If I understand correctly, tlmgr update begins reading texlive.tlpdb, 
then destroys it in order to rewrite it as the update goes. This seems 
very unsafe.

In lieu of splitting the file (which I understand would break things), 
maybe the old texlive.tlpdb could be left untouched until the update 
finishes (that would mean renaming it, or writing the new data to 
another file). In case of a problem, one could retrieve the old file and 
perform the update again, would one not ?

Downloading everything to a temporary location and then actually 
upgrading might be helpful too (since packages are downloaded as 
compressed files, I think there is a such a step already, you do not 
directly download to texmf-dist/...) : most outage risks occur because 
of downloads, so that would greatly reduce the risk of having to abort 
while the installation is in an inconsistent, partially upgraded, state.

Also, in my log from earlier, the update began with

Unable to download the checksum of the remote TeX Live database,
but found a local copy, so using that.


I take it this is a sign something is wrong either on the mirror or in 
the network : maybe the user should be offered the option to abort 
updating there and then ? I could not find the error string in TLPDB.pm, 
and reading though the Perl syntax is a bit tough, so I cannot be more 
precise.

-- 
Cordialement,

Yann Salmon