Test MSRV builds (without dev-dependencies) in CI

Author: TheBlueMatt

Cargo.toml

@@ -14,6 +14,7 @@ exclude = [
     "lightning-custom-message",
     "lightning-transaction-sync",
     "no-std-check",
+    "msrv-no-dev-deps-check",
     "bench",
 ]
 

ci/ci-tests.sh

@@ -4,6 +4,15 @@ set -eox pipefail
 RUSTC_MINOR_VERSION=$(rustc --version | awk '{ split($2,a,"."); print a[2] }')
 HOST_PLATFORM="$(rustc --version --verbose | grep "host:" | awk '{ print $2 }')"
 
+# Before pinning anything (most of which are dev-dependeicnes), check that we can build
+pushd msrv-no-dev-deps-check
+
+# The serde_json crate switched to Rust edition 2021 starting with v1.0.101, i.e., has MSRV of 1.56
+[ "$RUSTC_MINOR_VERSION" -lt 56 ] && cargo update -p serde_json --precise "1.0.100" --verbose
+
+cargo check
+popd
+
 # Tokio MSRV on versions 1.17 through 1.26 is rustc 1.49. Above 1.26 MSRV is 1.56.
 [ "$RUSTC_MINOR_VERSION" -lt 49 ] && cargo update -p tokio --precise "1.14.1" --verbose
 [[ "$RUSTC_MINOR_VERSION" -gt 48  &&  "$RUSTC_MINOR_VERSION" -lt 56 ]] && cargo update -p tokio --precise "1.25.1" --verbose

msrv-no-dev-deps-check/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "msrv-check"
+version = "0.1.0"
+edition = "2018"
+
+[dependencies]
+lightning = { path = "../lightning" }
+lightning-block-sync = { path = "../lightning-block-sync", features = [ "rest-client", "rpc-client" ] }
+lightning-invoice = { path = "../lightning-invoice" }
+lightning-net-tokio = { path = "../lightning-net-tokio" }
+lightning-persister = { path = "../lightning-persister" }
+lightning-background-processor = { path = "../lightning-background-processor", features = ["futures"] }
+lightning-rapid-gossip-sync = { path = "../lightning-rapid-gossip-sync" }