all hals: reexport PAC if unstable-pac feature is set.

embassy-stm32/Cargo.toml

@@ -43,6 +43,12 @@ defmt-error = [ ]
 sdmmc-rs = ["embedded-sdmmc"]
 net = ["embassy-net", "vcell"]
 
+# Reexport stm32-metapac at `embassy_stm32::pac`.
+# This is unstable because semver-minor (non-breaking) releases of embassy-stm32 may major-bump (breaking) the stm32-metapac version.
+# If this is an issue for you, you're encouraged to directly depend on a fixed version of the PAC.
+# There are no plans to make this stable.
+unstable-pac = []
+
 # BEGIN GENERATED FEATURES
 # Generated by gen_features.py. DO NOT EDIT.
 stm32f030c6 = [ "stm32-metapac/stm32f030c6",]

embassy-stm32/src/lib.rs

@@ -6,6 +6,9 @@
 #![feature(type_alias_impl_trait)]
 #![allow(incomplete_features)]
 
+#[cfg(feature = "unstable-pac")]
+pub use stm32_metapac as pac;
+#[cfg(not(feature = "unstable-pac"))]
 pub(crate) use stm32_metapac as pac;
 
 // This must go FIRST so that all the other modules see its macros.