err: introspection on non-fed graphs

crates/rover-client/src/error.rs

@@ -108,4 +108,7 @@ pub enum RoverClientError {
     /// could not parse the latest version
     #[error("Could not get the latest release version")]
     UnparseableReleaseVersion,
+
+    #[error("This endpoint doesn't support subgraph introspection via the Query._service field")]
+    SubgraphIntrospectionNotAvailable,
 }

crates/rover-client/src/lib.rs

@@ -16,7 +16,6 @@ pub mod introspection;
 pub use error::RoverClientError;
 
 /// Module for actually querying studio
-#[allow(clippy::upper_case_acronyms)]
 pub mod query;
 
 /// Module for getting release info

crates/rover-client/src/query/subgraph/introspect.rs

@@ -24,8 +24,20 @@ pub fn run(
 ) -> Result<IntrospectionResponse, RoverClientError> {
     // let graph = variables.graph_id.clone();
     let variables = introspection_query::Variables {};
-    let response_data = client.post::<IntrospectionQuery>(variables, headers)?;
-    build_response(response_data)
+    let response_data = client.post::<IntrospectionQuery>(variables, headers);
+    match response_data {
+        Ok(data) => build_response(data),
+        Err(e) => {
+            // this is almost definitely a result of a graph not
+            // being federated, or not matching the federation spec
+            if e.to_string().contains("Cannot query field") {
+                Err(RoverClientError::SubgraphIntrospectionNotAvailable)
+            } else {
+                Err(e)
+            }
+        }
+    }
+    // build_response(response_data)
 }
 
 fn build_response(

src/error/metadata/mod.rs

@@ -44,7 +44,8 @@ impl From<&mut anyhow::Error> for Metadata {
                 | RoverClientError::SendRequest(_)
                 | RoverClientError::MalformedResponse { null_field: _ }
                 | RoverClientError::InvalidSeverity => (Some(Suggestion::SubmitIssue), None),
-                RoverClientError::ExpectedFederatedGraph { graph: _ } => {
+                RoverClientError::SubgraphIntrospectionNotAvailable
+                | RoverClientError::ExpectedFederatedGraph { graph: _ } => {
                     (Some(Suggestion::UseFederatedGraph), None)
                 }
                 RoverClientError::NoSchemaForVariant {

src/error/metadata/suggestion.rs

@@ -59,7 +59,7 @@ impl Display for Suggestion {
                 )
             }
             Suggestion::UseFederatedGraph => {
-                "Try running the command on a valid federated graph.".to_string()
+                "Try running the command on a valid federated graph or use the appropriate `rover graph` command instead of `rover subgraph`.".to_string()
             }
             Suggestion::CheckGraphNameAndAuth => {
                 "Make sure your graph name is typed correctly, and that your API key is valid. (Are you using the right profile?)".to_string()