fix(exec::Req): pub(crate) -> pub, fixes public api

.changesets/fix_aaron_execution_request_builder_visibility.md

@@ -0,0 +1,7 @@
+### Fix visibility of SubscriptionTaskParams
+
+We had SubscriptionTaskParams set as pub and folks started using a builder that has it as its argument (the fake_bulder off of execution::Request); with the change in visibility, they weren't able to compile unit tests for their plugins
+
+New docs test (compiled as an external crate so a good test of the public API's visibility) and a couple of WARNs to make sure we don't make that same mistake again
+
+By [@aaronarinder](https://github.com/aaronarinder) in https://github.com/apollographql/router/pull/8771

apollo-router/src/plugins/subscription/execution.rs

@@ -119,7 +119,12 @@ where
     }
 }
 
-pub(crate) struct SubscriptionTaskParams {
+// WARN: you might be tempted to change this to pub(crate) because its fields are pub(crate) and
+// there's no actual use in having it marked pub _apart_ from it being used in the
+// execution::Request builder and, more importantly, the fake_builder we get from BuildStructor.
+// Customers use that in unit tests for their plugins, and they'll fail to compile if we mark this
+// pub(crate)
+pub struct SubscriptionTaskParams {
     pub(crate) client_sender: tokio::sync::mpsc::Sender<Response>,
     pub(crate) subscription_handle: SubscriptionHandle,
     pub(crate) subscription_config: SubscriptionConfig,

apollo-router/src/services/execution.rs

@@ -79,8 +79,23 @@ impl Request {
     /// This is the constructor (or builder) to use when constructing a "fake" ExecutionRequest.
     ///
     /// This does not enforce the provision of the data that is required for a fully functional
-    /// ExecutionRequest. It's usually enough for testing, when a fully consructed ExecutionRequest is
-    /// difficult to construct and not required for the pusposes of the test.
+    /// ExecutionRequest. It's usually enough for testing, when a fully constructed ExecutionRequest is
+    /// difficult to construct and not required for the purposes of the test.
+    ///
+    /// # Example
+    /// ```
+    /// use apollo_router::services::execution;
+    /// use apollo_router::Context;
+    ///
+    /// // This builder must remain usable from external crates for plugin testing.
+    /// let request = execution::Request::fake_builder()
+    ///     .context(Context::default())
+    ///     .build();
+    /// ```
+    // WARN: make sure to keep the example in the doc test; it gets compiled as an external crate,
+    // which is very useful in determining whether the public API has changed. In particular, we
+    // had an issue with SubscriptionTaskParams going from pub to pub(crate), preventing folks from
+    // compiling their unit tests for plugins because of the visibility change for the fake_builder
     #[builder(visibility = "pub")]
     fn fake_new(
         supergraph_request: Option<http::Request<graphql::Request>>,