--web-bundle for v2 CLI: fix #1002 and allow overrides

[bryango]

This PR is split off from #1131. See #1131 for relevant discussions on the web bundle interface.

1. Fixes Provide options for V2 cli to override the default bundle_url #1002: It enables us to override the default web bundle for the v2 CLI tectonic -X new and tectonic -X init, with the usual --web-bundle flag
2. Allows overrides: It allows user overrides of the --web-bundle by specifying it multiple times. The last specification of --web-bundle wins.
3. tectonic -X build is special as it never reads from the global config, but only from the local Tectonic.toml file, for maximal reproducibility. In this case, the global --web-bundle option, if specified, is ignored with a warning.

For a horrible example,

tectonic \
  --web-bundle "https://this-url-gets-overridden-1" \
  -X \
  --web-bundle "https://this-url-gets-overridden-2" \
  new \
  --web-bundle "https://this-url-gets-overridden-3" \
  --web-bundle "https://this-url-is-actually-used"

[codecov]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (c64e524) 46.28% compared to head (61eb46a) 46.34%.

Files	Patch %	Lines
src/bin/tectonic/main.rs	91.66%	1 Missing ⚠️
src/bin/tectonic/v2cli.rs	94.44%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1132      +/-   ##
==========================================
+ Coverage   46.28%   46.34%   +0.06%     
==========================================
  Files         171      171              
  Lines       65099    65121      +22     
==========================================
+ Hits        30129    30181      +52     
+ Misses      34970    34940      -30     

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[bryango]

Whoops, I should write tests, but I don't know how to... 😿
Update: I learned and have written extensive tests. Rust is an addictive language!

[doronbehar]

Whoops, I should write tests, but I don't know how to... 😿

You may want to do that after upstream approves the intentions of the PR.

I have a question: Is it possible to implement the following behavior:

tectonic --web-bundle <URL1> document.tex # Uses URL1
tectonic --web-bundle <URL1> --web-bundle <URL2> document.tex # Uses URL2
tectonic --web-bundle <URL1> -X build # Uses URL1
tectonic --web-bundle <URL1> -X build --web-bundle <URL2> # Uses URL2
tectonic --web-bundle <URL1> -X --web-bundle <URL2> build # Uses URL2

This way, the PR would help a lot both Nixpkgs' situation, and all other users. For Nix users, this would allow to wrap Tectonic with --add-flags (see this), and for other users it'd allow to simply add a shell alias such as:

alias tectonic='tectonic --web-bundle=<URL that matches my biber version>'

With the above described behavior to be able to override the web-bundle, a no-Nix user won't need to unalias the tectonic alias, and Nix users won't need to use the tectonic-unwrapped derivation. This is the ideal solution IMO to the issue, that is the least intrusive.

[doronbehar]

@bryango this seems to get into great shape! Considering you have added extensive tests, do you think it should be ready for inclusion in Nixpkgs? Along with an additional makeWrapper argument --add-flags?

[bryango]

Hi @doronbehar! Thank you very much for following along! I like your previous suggestions very much and have been trying to implement them.

do you think it should be ready for inclusion in Nixpkgs? Along with an additional makeWrapper argument --add-flags?

This is the eventual goal! I think I finally got everything working, but I am not entirely satisfied about the current resolution. The code feels a bit too hacky... I will try to improve it a bit more, and after some more testing, I think it would be good to go into nixpkgs! But it might take some time 🥺

[bryango]

@pkgw @doronbehar @rm-dr Happy new year! I think this is the best I can do, and it's ready for review. The changes may look large and scattered, but in fact half of them are test changes. It is easy to review commit by commit: https://github.com/tectonic-typesetting/tectonic/pull/1132/commits

• Each commit is "bite-sized" and has a clear objective stated in its message.
• The package is buildable at every commit and passes cargo test.
• The first few commits are refactors of the current behavior, and the latter ones add new --web-bundle options.

Going through the history, maybe @Sinofine @CraftSpider would be interested in taking a look?

[pkgw]

Sorry for taking to long to review this ☹️

Upon first read I wasn't a fan of the changes to allow -X later in the command line, but I am guessing that the motivation there is to make it possible to set up some kind of alias mytectonic = tectonic --web-bundle=https://...../ and Things Will Work. So, that seems reasonable.

Likewise I don't love having the -X build command accept a non-functional --web-bundle argument, but the homogeneity also helps with the above.

So I'm going to go ahead and merge this. Sorry again for the lack of responsiveness.

[bryango]

Thank you very much for merging this!

Upon first read I wasn't a fan of the changes to allow -X later in the command line, but I am guessing that the motivation there is to make it possible to set up some kind of alias mytectonic = tectonic --web-bundle=https://...../ and Things Will Work. So, that seems reasonable.

The current solution is indeed ugly, but once v2 CLI has fully taken over, this would hopefully look a bit better!

So I'm going to go ahead and merge this. Sorry again for the lack of responsiveness.

Please there is no need to apologize! It is already hard enough to work in academics, let alone maintaining many open source codebases where users like me are constantly blabbing for features 😆 Thank you very much for doing this!