Xtensa esp(up) toolchain not pulled in?

[brainstorm]

Hello,

I'm trying to setup my own local environment to compile/test embassy to followup on embassy-rs/embassy#4957 locally (without spending your GitHub CI worker minutes).

The tool pulls in a variety of rust toolchains by default, but seems to fail on ESP32S2?:

$ cargo embassy-devtool prepare-release embassy-sync
2025-12-08T05:23:22.508Z INFO  [cargo_embassy_devtool::cmd::semver_check] Building doc json for embassy-sync with features: ["defmt"]
2025-12-08T05:23:22.508Z DEBUG [cargo_embassy_devtool::cmd::semver_check] [
    "+nightly-2025-06-29",
    "rustdoc",
    "--lib",
    "--output-format=json",
    "-Zunstable-options",
    "-Zhost-config",
    "-Ztarget-applies-to-host",
    "-Zbuild-std=alloc,core",
    "--target=xtensa-esp32s2-none-elf",
    "--features=defmt",
    "--config=host.rustflags=[\"--cfg=instability_disable_unstable_docs\"]",
]
Running `cargo +nightly-2025-06-29 rustdoc --lib --output-format=json -Zunstable-options -Zhost-config -Ztarget-... (253 chars)` in "/home/rvalls/dev/personal/embassy/releaser/target/embassy-sync-0.7.2" - Environment [("RUSTDOCFLAGS", "--cfg docsrs --cfg not_really_docsrs --cfg semver_checks")]
   Compiling compiler_builtins v0.1.160 (/home/rvalls/.rustup/toolchains/nightly-2025-06-29-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/compiler-builtins/compiler-builtins)
   Compiling core v0.0.0 (/home/rvalls/.rustup/toolchains/nightly-2025-06-29-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core)
   Compiling defmt v1.0.1
   Compiling embedded-io-async v0.6.1
   Compiling heapless v0.8.0
   Compiling embassy-sync v0.7.2 (/home/rvalls/dev/personal/embassy/releaser/target/embassy-sync-0.7.2)
'esp32s2' is not a recognized processor for this target (ignoring processor)
'+forced-atomics' is not a recognized feature for this target (ignoring feature)
'esp32s2' is not a recognized processor for this target (ignoring processor)
'esp32s2' is not a recognized processor for this target (ignoring processor)
'+forced-atomics' is not a recognized feature for this target (ignoring feature)
'esp32s2' is not a recognized processor for this target (ignoring processor)
error: data-layout for target `xtensa-esp32s2-none-elf`, `e-m:e-p:32:32-v1:8:8-i64:64-i128:128-n32`, differs from LLVM target's `xtensa-none-elf` default layout, `e-m:e-p:32:32-i8:8:32-i16:16:32-i64:64-n32`

'esp32s2' is not a recognized processor for this target (ignoring processor)
'+forced-atomics' is not a recognized feature for this target (ignoring feature)
'esp32s2' is not a recognized processor for this target (ignoring processor)
'esp32s2' is not a recognized processor for this target (ignoring processor)
'+forced-atomics' is not a recognized feature for this target (ignoring feature)
'esp32s2' is not a recognized processor for this target (ignoring processor)
error: could not compile `core` (lib) due to 1 previous error
warning: build failed, waiting for other jobs to finish...
'esp32s2' is not a recognized processor for this target (ignoring processor)
'+forced-atomics' is not a recognized feature for this target (ignoring feature)
'esp32s2' is not a recognized processor for this target (ignoring processor)
'esp32s2' is not a recognized processor for this target (ignoring processor)
'+forced-atomics' is not a recognized feature for this target (ignoring feature)
'esp32s2' is not a recognized processor for this target (ignoring processor)
error: could not compile `compiler_builtins` (lib) due to 1 previous error
Error: Failed to execute cargo subcommand `cargo +nightly-2025-06-29 rustdoc --lib --output-format=json -Zunstable-options -Zhost-config -Ztarget-... (253 chars)`

$ clang --version
Ubuntu clang version 18.1.3 (1ubuntu1)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin

$ /home/rvalls/.rustup/toolchains/esp/xtensa-esp-elf/esp-14.2.0_20240906/xtensa-esp-elf/bin/xtensa-esp32s2-elf-cc --version
xtensa-esp-elf-cc (crosstool-NG esp-14.2.0_20240906) 14.2.0
Copyright (C) 2024 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ espup --version
espup 0.16.0

I guess I should pin/lock to revisions like you do in this Xtensa CI script?:

https://github.com/embassy-rs/embassy/blob/main/.github/ci/build-xtensa.sh

In other words, do you regularly use cargo-embassy-devtool locally to build embassy (and prepare releases) or do you mainly rely on the CI setup nowadays?

EDIT: Should I install cargo-embassy-devtool pinned to the commit revision pointed by this?: embassy-rs/embassy@27df928

[brainstorm]

If I understand correctly, embassy also requires a fork of cargo that contains the batch subcommand? Otherwise:

embassy-sync$ cargo embassy-devtool build
Running `cargo batch --- build --release --manifest-path=/home/rvalls/dev/personal/embassy/examples/mspm0c1104/C... (173 chars)` in "/home/rvalls/dev/personal/embassy" - Environment {"DEFMT_RTT_BUFFER_SIZE": "72"}
error: no such command: `batch`

help: a command with a similar name exists: `bench`

[lulf]

I generally run ci.sh in the embassy folder to run a build. It should print these warnings/instructions on the tools you need to install:

cargo install --git https://github.com/embassy-rs/cargo-batch cargo --bin cargo-batch --locked
cargo install --git https://github.com/embassy-rs/cargo-embassy-devtool --locked