use drift to detect API compatibility (#1)

Use https://docs.rs/drift (written by ahl) to detect whether two
documents are wire-compatible. I've tested this out with the changes
introduced in newtype-uuid 1.3.0, and it appears to correctly detect
that they're wire-identical (yay).

Author: sunshowers

.github/workflows/ci.yml

@@ -46,6 +46,10 @@ jobs:
       RUSTFLAGS: -D warnings
     steps:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+      # The e2e-example tests require origin/main to be present.
+      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+        with:
+          ref: main
       - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: ${{ matrix.rust-version }}

Cargo.lock

@@ -21,6 +21,7 @@ atomicwrites = "0.4.4"
 camino = "1.2.0"
 clap = "4.5"
 debug-ignore = "1.0.5"
+drift = "0.1.0"
 dropshot = "0.16.4"
 dropshot-api-manager = { path = "crates/dropshot-api-manager", version = "0.2.0" }
 dropshot-api-manager-types = { path = "crates/dropshot-api-manager-types", version = "0.2.0" }

Cargo.toml

@@ -132,6 +132,14 @@ impl ApiSpecFileName {
         }
     }
 
+    /// For versioned APIs, returns the version part of the filename
+    pub fn version(&self) -> Option<&semver::Version> {
+        match &self.kind {
+            ApiSpecFileNameKind::Lockstep => None,
+            ApiSpecFileNameKind::Versioned { version, .. } => Some(version),
+        }
+    }
+
     /// For versioned APIs, returns the hash part of the filename
     pub fn hash(&self) -> Option<&str> {
         match &self.kind {

crates/dropshot-api-manager-types/src/validation.rs

@@ -15,6 +15,7 @@ atomicwrites.workspace = true
 camino.workspace = true
 clap = { workspace = true, features = ["cargo", "derive", "env"] }
 debug-ignore.workspace = true
+drift.workspace = true
 dropshot.workspace = true
 fs-err.workspace = true
 hex.workspace = true