The Ubuntu MIR process require rust packages in Ubuntu to have their crates vendored, see https://github.com/canonical/ubuntu-mir/blob/main/vendoring/Rust.md

The page describe the steps we are currently taking to do the vendoring for our GNOME packages as part of gnome-team@salsa

Create a new Ubuntu repository

The vendored crates are often large and to avoid adding that extra cost to the Debian repository we create a fork under the ubuntu-dev-team namespace

1. Use gbp clone to clone the Debian repository

2. Create the Ubuntu branch

$ git checkout -b ubuntu/latest

3. Edit debian/gbp.conf

Add 'debian-tag = ubuntu/%(version)s' to the [DEFAULT] section of debian/gbp

Edit debian-branch to set it to 'ubuntu/latest'

4. Update changelog and control

$ dch -i "Vendor the crates for Ubuntu"
$ update-maintainer
$ sed -i 's/gnome-team/ubuntu-dev-team/' debian/control

5. git commit all these changes

$ git commit debian -m "Creating Ubuntu branch"

6. Fork the Salsa repository to ubuntu-dev-team

Go on https://salsa.debian.org/gnome-team/$PROJECT/-/forks/new , select ubuntu-dev-team (you need to be a member) and “only the default branch” option.

7. Push your work

$ git push --set-upstream [email protected]:ubuntu-dev-team/<PROJECT>.git

8. Change the default branch

Visit https://salsa.debian.org/ubuntu-dev-team/<PROJECT>/-/settings/repository#branch-defaults-settings

Set the default branch to ubuntu/latest

Visit Code > Branches and delete the debian/latest branch.

Vendor the crates

1. Update debian patches

Remove any Debian debian/patches modifying Cargo.toml's dependencies from the series

2. Add a patch to tell Cargo to use our vendored source instead of looking online

create debian/patches/use-vendored-crates.patch and add it to the series

   1 Subject: Use the vendored crates to build without network access
   2 
   3 Forwarded: not-needed
   4 ---
   5  .cargo/config | 5 +++++
   6  1 file changed, 5 insertions(+)
   7  create mode 100644 .cargo/config
   8 
   9 diff --git a/.cargo/config b/.cargo/config
  10 new file mode 100644
  11 index 0000000..8c56c72
  12 --- /dev/null
  13 +++ b/.cargo/config
  14 @@ -0,0 +1,5 @@
  15 +[source.crates-io]
  16 +replace-with = "debian"
  17 +
  18 +[source.debian]
  19 +directory = "debian/missing-sources"
  20 

 3. Disable all librust* Build-Depends in debian/control

$ sed -i 's/ librust/# librust/#' debian/control

4. Add debian/.gitingore to avoid static libraries

debian/.gitignore:

   1 !missing-sources/**
   2 /missing-sources/**/*.a

$ git add debian/.gitignore

5. Vendor the crates

It requires 'cargo-vendor-filterer' to be installed

In case of refresh

$ rm -rf debian/missing-sources/

Then

$ cargo vendor-filterer --platform='*-*-linux-gnu' --platform '*-*-linux-gnueabi' --all-features debian/missing-sources/
$ git add debian/missing-sources
$ git commit -m "Include vendored crates"

Generate the orig tarball with gbp or download it with apt source $package

$ dpkg-source --include-binaries -b .
$ git add debian/source/include-binaries
$ git commit -m "Update debian/source/include-binaries"

revert the applied patches and clean .pc

$ git reset --hard && git clean -fdx

6. Generate XS-Vendored-Sources-Rust and add it to debian/control

$ rm Cargo.toml

$ CARGO_VENDOR_DIR=debian/missing-sources/ /usr/share/cargo/bin/dh-cargo-vendored-sources

Add the the XS-Vendored-Sources-Rust definition to the top section of debian/control (before Standards-Version works for example)

Commit the changes and reset the Vcs state

git add debian/control
git commit -m "Define vendored crates as XS-Vendored-Sources-Rust"
git reset --hard # restore Cargo.toml

7. Simplify debian/rules and make minor changes

• Remove dh-cargo rules
• Add execute_before_dh_auto_build and execute_after_dh_auto_build sections

example https://salsa.debian.org/ubuntu-dev-team/papers/-/commit/a65b36b8

8. Include vendoring README

example https://salsa.debian.org/ubuntu-dev-team/papers/-/blob/ubuntu/latest/debian/README.source

Refresh the crates

Replay the step 5. and 6. from the previous section

Patches

If you have patches that modify Cargo.toml's dependencies, then you'll need to apply the patches before running cargo vendor. Patching Cargo.toml may not be needed since we are vendoring all the Rust crates. Perhaps it is needed in the future if we figure out how to exclude unnecessary Windows crates or if there is a subset of Rust crates that are shipped by the system.

If you're using git-buildpackage, gbp pq import before the first rm command and gbp pq export after the cargo vendor command takes care of this.