Use native check-cfg lint in cargo beta

This uses the newly introduced conditional configuration checks that are
now configurable withint Cargo (beta).

This allows us to get rid of our custom python script that checks for
expected features and cfgs.

This does introduce a warning regarding the unknown lint in Cargo
versions prior to the current beta, but since these are not rustc errors,
they won't break any builds with the "-D warnings" RUSTFLAG.

Moving to this lint actually exposed the "strict" feature not being
present in the lightning-invoice crate, as our python script didnt
correctly parse the cfg_attr where it appeared.

Author: dunxen

.github/workflows/build.yml

@@ -32,8 +32,6 @@ jobs:
         run: |
           rustup target add thumbv7m-none-eabi
           sudo apt-get -y install gcc-arm-none-eabi
-      - name: Check for unknown cfg tags
-        run: ci/check-cfg-flags.py
       - name: shellcheck the CI script
         if: "matrix.platform == 'ubuntu-latest'"
         run: |

Cargo.toml

@@ -42,3 +42,25 @@ panic = "abort"
 
 [patch.crates-io.possiblyrandom]
 path = "possiblyrandom"
+
+[workspace.lints.rust.unexpected_cfgs]
+level = "forbid"
+# When adding a new cfg attribute, ensure that it is added to this list.
+#
+# Note that Cargo automatically declares corresponding cfgs for every feature
+# defined in the member-level [features] tables as "expected".
+check-cfg = [
+    "cfg(fuzzing)",
+    "cfg(secp256k1_fuzz)",
+    "cfg(hashes_fuzz)",
+    "cfg(test)",
+    "cfg(debug_assertions)",
+    "cfg(c_bindings)",
+    "cfg(ldk_bench)",
+    "cfg(taproot)",
+    "cfg(async_signing)",
+    "cfg(require_route_graph_test)",
+    "cfg(dual_funding)",
+    "cfg(splicing)",
+    "cfg(async_payments)",
+]

ci/check-cfg-flags.py

@@ -30,3 +30,6 @@ tokio = { version = "1.35", features = [ "macros", "rt", "rt-multi-thread", "syn
 lightning = { version = "0.0.123-beta", path = "../lightning", features = ["_test_utils"] }
 lightning-invoice = { version = "0.31.0-beta", path = "../lightning-invoice" }
 lightning-persister = { version = "0.0.123-beta", path = "../lightning-persister" }
+
+[lints]
+workspace = true

lightning-background-processor/Cargo.toml

@@ -28,3 +28,6 @@ chunked_transfer = { version = "1.4", optional = true }
 [dev-dependencies]
 lightning = { version = "0.0.123-beta", path = "../lightning", features = ["_test_utils"] }
 tokio = { version = "1.35", features = [ "macros", "rt" ] }
+
+[lints]
+workspace = true

lightning-block-sync/Cargo.toml

@@ -16,3 +16,6 @@ rustdoc-args = ["--cfg", "docsrs"]
 [dependencies]
 bitcoin = "0.31.2"
 lightning = { version = "0.0.123-beta", path = "../lightning" }
+
+[lints]
+workspace = true

lightning-custom-message/Cargo.toml

@@ -18,6 +18,7 @@ rustdoc-args = ["--cfg", "docsrs"]
 default = ["std"]
 no-std = ["lightning/no-std"]
 std = ["bitcoin/std", "lightning/std", "bech32/std"]
+strict = []
 
 [dependencies]
 bech32 = { version = "0.9.1", default-features = false }
@@ -31,3 +32,6 @@ lightning = { version = "0.0.123-beta", path = "../lightning", default-features
 hex = { package = "hex-conservative", version = "0.1.1", default-features = false }
 serde_json = { version = "1"}
 hashbrown = { version = "0.13", default-features = false }
+
+[lints]
+workspace = true

lightning-invoice/Cargo.toml

@@ -22,3 +22,6 @@ tokio = { version = "1.35", features = [ "rt", "sync", "net", "time" ] }
 [dev-dependencies]
 tokio = { version = "1.35", features = [ "macros", "rt", "rt-multi-thread", "sync", "net", "time" ] }
 lightning = { version = "0.0.123-beta", path = "../lightning", features = ["_test_utils"] }
+
+[lints]
+workspace = true

lightning-net-tokio/Cargo.toml

@@ -26,3 +26,6 @@ criterion = { version = "0.4", optional = true, default-features = false }
 [dev-dependencies]
 lightning = { version = "0.0.123-beta", path = "../lightning", features = ["_test_utils"] }
 bitcoin = { version = "0.31.2", default-features = false }
+
+[lints]
+workspace = true

lightning-persister/Cargo.toml

@@ -23,3 +23,6 @@ criterion = { version = "0.4", optional = true, default-features = false }
 
 [dev-dependencies]
 lightning = { version = "0.0.123-beta", path = "../lightning", features = ["_test_utils"] }
+
+[lints]
+workspace = true

lightning-rapid-gossip-sync/Cargo.toml

@@ -39,3 +39,6 @@ electrsd = { version = "0.27.3", default-features = false, features = ["legacy",
 
 [target.'cfg(all(not(target_os = "windows"), no_download))'.dev-dependencies]
 electrsd = { version = "0.27.3", default-features = false, features = ["legacy"] }
+
+[lints]
+workspace = true

lightning-transaction-sync/Cargo.toml

@@ -65,3 +65,6 @@ criterion = { version = "0.4", optional = true, default-features = false }
 
 [target.'cfg(taproot)'.dependencies]
 musig2 = { git = "https://github.com/arik-so/rust-musig2", rev = "739533fc" }
+
+[lints]
+workspace = true

lightning/Cargo.toml

@@ -19,3 +19,6 @@ getrandom = { version = "0.2", optional = true, default-features = false }
 # Enable getrandom if we are on a platform that (likely) supports it
 [target.'cfg(not(any(target_os = "unknown", target_os = "none")))'.dependencies]
 getrandom = { version = "0.2", default-features = false }
+
+[lints]
+workspace = true