FF-2839 fix: update ruby-sdk/Cargo.lock to include eppo_core from cra…

…tes.io (#16)

.github/workflows/ci.yml

@@ -49,6 +49,17 @@ jobs:
       - run: npm ci
       - run: make test-data
 
+      - name: Check Cargo.lock
+        # Ensure that Cargo.lock matches Cargo.toml
+        run: cargo generate-lockfile --locked
+        working-directory: ruby-sdk
+
+      - name: Override eppo_core for testing
+        run: |
+          mkdir -p ~/.cargo/
+          echo "[patch.crates-io.eppo_core]" >> "${CARGO_HOME:-$HOME/.cargo}/config.toml"
+          echo "path = '$PWD/eppo_core'" >> "${CARGO_HOME:-$HOME/.cargo}/config.toml"
+
       - name: Install dependencies
         run: bundle install
         working-directory: ruby-sdk

ruby-sdk/.gitignore

@@ -16,3 +16,7 @@ target/
 
 # rspec failure tracking
 .rspec_status
+
+# .cargo/config.toml should be used for testing with local version of
+# eppo_core but it should not be committed.
+/.cargo/config.toml

ruby-sdk/README.md

@@ -6,3 +6,17 @@ Refer to our [SDK documentation](https://docs.geteppo.com/feature-flags/sdks/rub
 
 ## Supported Ruby Versions
 This version of the SDK is compatible with Ruby 3.0.6 and above.
+
+# Contributing
+
+## Testing with local version of `eppo_core`
+
+To run build and tests against a local version of `eppo_core`, you should instruct Cargo to look for it at the local path.
+
+Add the following to `.cargo/config.toml` file (relative to `ruby-sdk`):
+```toml
+[patch.crates-io]
+eppo_core = { path = '../eppo_core' }
+```
+
+Make sure you remove the override before updating `Cargo.lock`. Otherwise, the lock file will be missing `eppo_core` checksum and will be unsuitable for release. (CI will warn you if you do this accidentally.)