cargo: Allow filtering packages by name #325

aleb · 2022-10-12T21:03:58Z

Cargo.lock might contain unwanted packages.

gasinvein · 2022-10-12T21:23:39Z

Can you please explain when and why it could be useful?
Cargo.lock contains complete list of the project's dependencies, and omitting any of them is expected to result in a broken build. So, why someone would want that is definitely not obvious.

aleb · 2022-10-12T21:32:48Z

For example out of https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs we want only package "gst-plugin-gtk4", nothing else.

gst-plugins-rs $ ../flatpak-builder-tools/cargo/flatpak-cargo-generator.py Cargo.lock -o x.json
gst-plugins-rs $ ../flatpak-builder-tools/cargo/flatpak-cargo-generator.py Cargo.lock -p gst-plugin-gtk4 -o z.json
gst-plugins-rs $ ls -l *.json
-rw-r--r-- 1 aleb users 248779 12. Okt 21:43 x.json
-rw-r--r-- 1 aleb users  62082 12. Okt 22:57 z.json

gasinvein · 2022-10-12T21:40:17Z

I don't see a lockfile in the project you've linked, where does the Cargo.lock come from?

aleb · 2022-10-12T21:42:40Z

https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html

If you’re building a non-end product, such as a rust library that other rust packages will depend on, put Cargo.lock in your .gitignore.

aleb · 2022-10-12T21:43:46Z

You can cargo fetch to create the Cargo.lock file when it's missing.

gasinvein · 2022-10-12T21:49:21Z

I still fail to understand what you're trying to achieve and what could be the reason for excluding cargo dependencies from a lockfile.

Just to be clear, to avoid possible misunderstandings: the flatpak-cargo-generator.py script doesn't build anything, neither cause anything to be installed. It only pre-fetches cargo packages cache (via flatpak-builder), very similar to what cargo vendor does (and largely replicating its behaviour). What to build and what not to is still up to Cargo.

aleb · 2022-10-12T22:10:00Z

For example out of https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs we want only package "gst-plugin-gtk4", nothing else.

gst-plugins-rs $ cargo build --package 2>&1 | grep gst | sort
    gst-plugin-audiofx
    gst-plugin-aws
    gst-plugin-cdg
    gst-plugin-claxon
    gst-plugin-closedcaption
    gst-plugin-csound
    gst-plugin-dav1d
    gst-plugin-fallbackswitch
    gst-plugin-ffv1
    gst-plugin-file
    gst-plugin-flavors
    gst-plugin-fmp4
    gst-plugin-gif
    gst-plugin-gtk4
    gst-plugin-hlssink3
    gst-plugin-hsv
    gst-plugin-json
    gst-plugin-lewton
    gst-plugin-onvif
    gst-plugin-raptorq
    gst-plugin-rav1e
    gst-plugin-regex
    gst-plugin-reqwest
    gst-plugin-rspng
    gst-plugin-rtpav1
    gst-plugin-sodium
    gst-plugin-spotify
    gst-plugin-textahead
    gst-plugin-textwrap
    gst-plugin-threadshare
    gst-plugin-togglerecord
    gst-plugin-tracers
    gst-plugin-tutorial
    gst-plugin-uriplaylistbin
    gst-plugin-version-helper
    gst-plugin-videofx
    gst-plugin-webp
    gst-plugin-webrtchttp

gasinvein · 2022-10-12T22:16:06Z

From a workspace project like this, you select package(s) to build via cargo. Again, flatpak-cargo-generator.py doesn't control what is being built in any way. You can generate sources for the whole gst-plugins-rs project, build still build only desired components.

aleb · 2022-10-12T23:13:33Z

Without the filtering we'd have to download a lot of stuff that's not needed, which is wasteful.

gasinvein · 2022-10-14T11:16:31Z

cargo vendor doesn't consider "redundant" packages and downloads all the project dependencies, why should we do otherwise?

aleb · 2022-10-14T12:41:28Z

Because we can! :)

cargo-vendor "Vendor all dependencies for a project locally". Why does it not allow to vendor only the deps of a single package? That I don't know.

As I said, gst-plugins-rs contains multiple libraries but we only need [to build] only one of them, not all. That's why we download only the dependencies for the corresponding package, not for all the packages in the project.

gasinvein · 2022-10-14T13:19:56Z