support/download/cargo-post-process: cargo output for vendor config

Use the output of `cargo vendor` to generate the vendor configuration.

Fixes the need to patch the generated configuration if there are
non-crates.io dependencies.

Note:
  `cargo vendor` currently prints a newline before it prints the
  needed configuration.

  This is fixed in +nightly, will end up in +stable soon and must
  be considered when updating cargo.
  See: https://github.com/rust-lang/cargo/pull/11273

  Until then it is needed to remove this first line to make sure
  that the contents of .cargo/config will be the same as they were
  generated with the earlier version of the script. Thus, the
  hashes of the packages that use this script remain the same.

Signed-off-by: Simon Richter <simon.richter@ptwdosimetry.com>
[yann.morin.1998@free.fr: add comment in rust-bin.mk and rust.mk]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/rust-bin/rust-bin.mk

@@ -4,6 +4,8 @@
 #
 ################################################################################
 
+# When updating this version, check whether support/download/cargo-post-process
+# still generates the same archives.
 RUST_BIN_VERSION = 1.64.0
 RUST_BIN_SITE = https://static.rust-lang.org/dist
 RUST_BIN_LICENSE = Apache-2.0 or MIT

package/rust/rust.mk

@@ -4,6 +4,8 @@
 #
 ################################################################################
 
+# When updating this version, check whether support/download/cargo-post-process
+# still generates the same archives.
 RUST_VERSION = 1.64.0
 RUST_SOURCE = rustc-$(RUST_VERSION)-src.tar.xz
 RUST_SITE = https://static.rust-lang.org/dist

support/download/cargo-post-process

@@ -1,6 +1,7 @@
 #!/usr/bin/env bash
 
 set -e
+set -o pipefail
 
 . "${0%/*}/helpers"
 
@@ -22,17 +23,28 @@ post_process_unpack "${base_name}" "${output}"
 
 # Do the Cargo vendoring
 pushd "${base_name}" > /dev/null
-cargo vendor --manifest-path ${BR_CARGO_MANIFEST_PATH-Cargo.toml} --locked VENDOR
 
 # Create the local .cargo/config with vendor info
+#
+# The first line of the output to stdout is empty.
+# So skip it to have the file start with the vendoring
+# configuration (`tail --lines=+2`).
+#
+# NOTE:
+#   There is  a patch for cargo to remove the first empty line:
+#   See: https://github.com/rust-lang/cargo/pull/11273
+#
+#   The patch already landed in +nightly and will end up
+#   in +stable soon.
+#
+# ->  When updating rust/cargo, the call to `tail` must be removed.
+#
 mkdir -p .cargo/
-cat <<EOF >.cargo/config
-[source.crates-io]
-replace-with = "vendored-sources"
+cargo vendor \
+    --manifest-path ${BR_CARGO_MANIFEST_PATH-Cargo.toml} \
+    --locked VENDOR \
+    | tail --lines=+2 | tee .cargo/config
 
-[source.vendored-sources]
-directory = "VENDOR"
-EOF
 popd > /dev/null
 
 post_process_repack "$(pwd)" "${base_name}" "${output}"