feat(ci): Add feature propagation checks

.config/zepter.yaml

@@ -0,0 +1,39 @@
+version:
+  format: 1
+  # Minimum zepter version that is expected to work. This is just for printing a nice error
+  # message when someone tries to use an older version.
+  binary: 0.13.2
+
+# The examples in the following comments assume crate `A` to have a dependency on crate `B`.
+workflows:
+  check:
+    - [
+        "lint",
+        # Check that `A` activates the features of `B`.
+        "propagate-feature",
+        # These are the features to check:
+        "--features=std,serde",
+        # Do not try to add a new section into `[features]` of `A` only because `B` expose that feature. There are edge-cases where this is still needed, but we can add them manually.
+        "--left-side-feature-missing=ignore",
+        # Ignore the case that `A` it outside of the workspace. Otherwise it will report errors in external dependencies that we have no influence on.
+        "--left-side-outside-workspace=ignore",
+        # limit to the workspace
+        "--workspace",
+        "--show-path",
+        "--quiet",
+      ]
+  default:
+    # Running `zepter` with no subcommand will check & fix.
+    - [$check.0, "--fix"]
+
+# Will be displayed when any workflow fails:
+help:
+  text: |
+    Maili uses the Zepter CLI to detect abnormalities in Cargo features, e.g. missing propagation.
+
+    It looks like one more checks failed; please check the console output.
+
+    You can try to automatically address them by installing zepter (`cargo install zepter --locked`) and simply running `zepter` in the workspace root.
+  links:
+    - "https://github.com/op-rs/maili/pull/134"
+    - "https://github.com/ggwpez/zepter"

.github/workflows/lint.yml

@@ -0,0 +1,22 @@
+name: lint
+
+on:
+  pull_request:
+  merge_group:
+  push:
+    branches: [main]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  # Check crates correctly propagate features
+  feature-propagation:
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    steps:
+      - uses: actions/checkout@v4
+      - run: |
+          cargo install zepter
+          zepter --version
+          time zepter run check

crates/network/Cargo.toml

@@ -25,3 +25,13 @@ alloy-network.workspace = true
 alloy-primitives.workspace = true
 alloy-rpc-types-eth.workspace = true
 alloy-signer.workspace = true
+
+[features]
+std = [
+	"op-alloy-consensus/std",
+	"op-alloy-rpc-types/std"
+]
+serde = [
+	"op-alloy-consensus/serde",
+	"op-alloy-rpc-types/serde"
+]

crates/op-alloy/Cargo.toml

@@ -30,9 +30,11 @@ op-alloy-rpc-types = { workspace = true, optional = true }
 default = ["std", "k256", "serde"]
 
 std = [
-  "op-alloy-consensus?/std",
-  "op-alloy-rpc-types?/std",
-  "op-alloy-rpc-types-engine?/std",
+	"op-alloy-consensus?/std",
+	"op-alloy-rpc-types?/std",
+	"op-alloy-rpc-types-engine?/std",
+	"op-alloy-network?/std",
+	"op-alloy-provider?/std"
 ]
 
 full = [
@@ -54,8 +56,11 @@ arbitrary = [
 ]
 
 serde = [
-  "op-alloy-consensus?/serde",
-  "op-alloy-rpc-types-engine?/serde",
+	"op-alloy-consensus?/serde",
+	"op-alloy-rpc-types-engine?/serde",
+	"op-alloy-network?/serde",
+	"op-alloy-provider?/serde",
+	"op-alloy-rpc-types?/serde"
 ]
 
 # `no_std` support

crates/provider/Cargo.toml

@@ -27,3 +27,11 @@ alloy-rpc-types-engine = { workspace = true, features = ["serde"] }
 
 # misc
 async-trait.workspace = true
+
+[features]
+std = [
+	"op-alloy-rpc-types-engine/std"
+]
+serde = [
+	"op-alloy-rpc-types-engine/serde"
+]

crates/rpc-types-engine/Cargo.toml

@@ -52,9 +52,10 @@ std = [
   "op-alloy-consensus/std",
 ]
 serde = [
-  "dep:serde",
-  "dep:alloy-serde",
-  "alloy-rpc-types-engine/serde",
+	"dep:serde",
+	"dep:alloy-serde",
+	"alloy-rpc-types-engine/serde",
+	"op-alloy-consensus/serde"
 ]
 arbitrary = [
   "std",

crates/rpc-types/Cargo.toml

@@ -46,10 +46,11 @@ similar-asserts.workspace = true
 [features]
 default = ["std"]
 std = [
-  "alloy-network-primitives/std",
-  "alloy-eips/std",
-  "alloy-primitives/std",
-  "alloy-rpc-types-eth/std",
+	"alloy-network-primitives/std",
+	"alloy-eips/std",
+	"alloy-primitives/std",
+	"alloy-rpc-types-eth/std",
+	"op-alloy-consensus/std"
 ]
 arbitrary = [
   "std",
@@ -62,3 +63,6 @@ k256 = [
   "alloy-rpc-types-eth/k256",
   "op-alloy-consensus/k256",
 ]
+serde = [
+	"op-alloy-consensus/serde"
+]