Vendoring the headers fails, the build still succeeds

[zauster]

When I install Xtensor.R, I see some errors about branches not found and files not being copied. You can see this actually even in your CI runs, e.g., here: https://github.com/xtensor-stack/Xtensor.R/actions/runs/20137003376/job/57793039614

** using staged installation
Vendoring of xtensor headers is enabled.
Cloning into 'xtl'...
warning: refs/tags/0.8.1 efc8da822fd16f23adf7c813f13b11b5372e823a is not a commit!
Note: switching to 'f3ca44e9102d574e9592c6917ae09da2bacf9aae'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by switching back to a branch.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -c with the switch command. Example:

  git switch -c <new-branch-name>

Or undo this operation with:

  git switch -

Turn off this advice by setting config variable advice.detachedHead to false

Cloning into 'xsimd'...
fatal: Remote branch 13.2.1 not found in upstream origin                  <====== xsimd failure
cp: cannot stat 'xsimd/include/xsimd': No such file or directory
Cloning into 'xtensor'...
warning: refs/tags/0.27.0 76f8eea4473655007a459aa1668330d62d19f089 is not a commit!
Note: switching to 'c7ae1a6aae85bed9f6bf912da78c70b3a7f49900'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by switching back to a branch.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -c with the switch command. Example:

  git switch -c <new-branch-name>

Or undo this operation with:

  git switch -

Turn off this advice by setting config variable advice.detachedHead to false

error: include/xtensor/xstorage.hpp: No such file or directory                           <======= xtensor failure
Cloning into 'xtensor-r'...
warning: refs/tags/0.17.0 49720cf0056962ba9a67d1b40ad0f0a0bed04a10 is not a commit!
Note: switching to '1c7093664db4fec3bf40487bd997af2b3a615c93'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by switching back to a branch.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -c with the switch command. Example:

  git switch -c <new-branch-name>

Or undo this operation with:

  git switch -

Turn off this advice by setting config variable advice.detachedHead to false

> library('Rcpp');Rcpp::compileAttributes();
> 
> 
** libs
using C++ compiler: ‘x86_64-conda-linux-gnu-c++ (conda-forge gcc 15.2.0-15) 15.2.0’
x86_64-conda-linux-gnu-c++ -std=gnu++17 -I"/home/runner/micromamba/envs/xtensor-dev/lib/R/include" -DNDEBUG  -I'/home/runner/micromamba/envs/xtensor-dev/lib/R/library/Rcpp/include' -DNDEBUG -D_FORTIFY_SOURCE=2 -O2 -isystem /home/runner/micromamba/envs/xtensor-dev/include -I/home/runner/micromamba/envs/xtensor-dev/include -Wl,-rpath-link,/home/runner/micromamba/envs/xtensor-dev/lib   -I../inst/include --std=c++20 -D_LIBCPP_DISABLE_AVAILABILITY -fpic  -fvisibility-inlines-hidden  -fmessage-length=0 -march=nocona -mtune=haswell -ftree-vectorize -fPIC -fstack-protector-strong -fno-plt -O2 -ffunction-sections -pipe -isystem /home/runner/micromamba/envs/xtensor-dev/include -fdebug-prefix-map=/home/conda/feedstock_root/build_artifacts/r-base-split_1763744198974/work=/usr/local/src/conda/r-base-4.4.3 -fdebug-prefix-map=/home/runner/micromamba/envs/xtensor-dev=/usr/local/src/conda-prefix   -c RcppExports.cpp -o RcppExports.o

The build then continues and even succeeds. The problem might arise only further downstream, when package want to use the supposedly-vendored headers, I guess.

• For the xsimd failure, it seems that it points to a non-existing branch. Should probably be 14.0.0 instead of 13.2.1
• For the xtensor failure: the pragmas patch points to the wrong file, I think.