Enable goto def in LSP to goto the actual schema definition (#4434)

Summary:
I basically just took captbaritone 's POC and made it configurable based on our conversation [on Threads](https://www.threads.net/janjonzen/post/CwwfXJ7LlL_)

This should be reasonably generalized to support different use-cases, but I'm open to rewriting all of this.

Pull Request resolved: #4434

Test Plan:
```
cd compiler
cargo build --release --bin relay
cd ../vscode-extension
yarn build-local
```

In a private project, I configured the new option and overrode the relay binary location:

```diff
+ "relay.pathToExtraDataProviderScript": "../scripts/graphql_lookup.sh",
+ "relay.pathToRelay": ".../relay/compiler/target/release/relay"
```

I manually installed the `relay-2.1.0.vsix` file in my VSCode and reloaded

I opened a file with a Relay GraphQL query in it and ctrl-clicked (goto def on my machine) and it went to the correct file!

Reviewed By: captbaritone

Differential Revision: D48955713

Pulled By: bigfootjon

fbshipit-source-id: 20f2a707e471c4a8a860711e5625887cf6e4ed70

Co-authored-by: Jordan Eldredge <jordan@jordaneldredge.com>

compiler/crates/relay-bin/src/main.rs

@@ -29,6 +29,9 @@ use relay_compiler::ProjectName;
 use relay_compiler::RemotePersister;
 use relay_lsp::start_language_server;
 use relay_lsp::DummyExtraDataProvider;
+use relay_lsp::FieldDefinitionSourceInfo;
+use relay_lsp::FieldSchemaInfo;
+use relay_lsp::LSPExtraDataProvider;
 use schema::SDLSchema;
 use schema_documentation::SchemaDocumentationLoader;
 use simplelog::ColorChoice;
@@ -108,6 +111,11 @@ struct LspCommand {
     /// Verbosity level
     #[clap(long, arg_enum, default_value = "quiet-with-errors")]
     output: OutputKind,
+
+    /// Script to be called to lookup the actual definition of a GraphQL entity for
+    /// implementation-first GraphQL schemas.
+    #[clap(long)]
+    locate_command: Option<String>,
 }
 
 #[derive(clap::Subcommand)]
@@ -306,13 +314,71 @@ async fn handle_compiler_command(command: CompileCommand) -> Result<(), Error> {
     Ok(())
 }
 
+struct ExtraDataProvider {
+    locate_command: String,
+}
+
+impl ExtraDataProvider {
+    pub fn new(locate_command: String) -> ExtraDataProvider {
+        ExtraDataProvider { locate_command }
+    }
+}
+
+impl LSPExtraDataProvider for ExtraDataProvider {
+    fn fetch_query_stats(&self, _search_token: &str) -> Vec<String> {
+        vec![]
+    }
+
+    fn resolve_field_definition(
+        &self,
+        project_name: String,
+        parent_type: String,
+        field_info: Option<FieldSchemaInfo>,
+    ) -> Result<Option<FieldDefinitionSourceInfo>, String> {
+        let entity_name = match field_info {
+            Some(field_info) => format!("{}.{}", parent_type, field_info.name),
+            None => parent_type,
+        };
+        let result = Command::new(&self.locate_command)
+            .arg(project_name)
+            .arg(entity_name)
+            .output()
+            .map_err(|e| format!("Failed to run locate command: {}", e))?;
+
+        let result = String::from_utf8(result.stdout).expect("Failed to parse output");
+
+        // Parse file_path:line_number:column_number
+        let result_trimmed = result.trim();
+        let result = result_trimmed.split(':').collect::<Vec<_>>();
+        if result.len() != 3 {
+            return Err(format!(
+                "Result '{}' did not match expected format. Please return 'file_path:line_number:column_number'",
+                result_trimmed
+            ));
+        }
+        let file_path = result[0];
+        let line_number = result[1].parse::<u64>().unwrap() - 1;
+
+        Ok(Some(FieldDefinitionSourceInfo {
+            file_path: file_path.to_string(),
+            line_number,
+            is_local: true,
+        }))
+    }
+}
+
 async fn handle_lsp_command(command: LspCommand) -> Result<(), Error> {
     configure_logger(command.output, TerminalMode::Stderr);
 
     let config = get_config(command.config)?;
 
+    let extra_data_provider: Box<dyn LSPExtraDataProvider + Send + Sync> =
+        match command.locate_command {
+            Some(locate_command) => Box::new(ExtraDataProvider::new(locate_command)),
+            None => Box::new(DummyExtraDataProvider::new()),
+        };
+
     let perf_logger = Arc::new(ConsoleLogger);
-    let extra_data_provider = Box::new(DummyExtraDataProvider::new());
     let schema_documentation_loader: Option<Box<dyn SchemaDocumentationLoader<SDLSchema>>> = None;
     let js_language_server = None;
 

vscode-extension/README.md

@@ -70,6 +70,15 @@ Path to a Relay config relative to the `rootDirectory`. Without this, the compil
 
 An array of project configuration in the form `{name: string, rootDirectory: string, pathToConfig: string}`. If omitted, it is assumed your workspace uses a single Relay config and the compiler will search for your config file. But you can also use this configuration if your Relay config is in a nested directory. This configuration must be used if your workspace has multiple Relay projects, each with their own config file.
 
+#### `relay.pathToLocateCommand` (default: `null`)
+
+Path to a script to look up the actual definition for a GraphQL entity for implementation-first GraphQL schemas. This script will be called for "goto definition" requests to the LSP instead of opening the schema.
+The script will be called with 2 arguments. The first will be the relay project name, the second will be either "Type" or "Type.field" (a type or the field of a type, repectively).
+The script must respond with a single line of output matching "/absolute/file/path:1:2" where "1" is the line number in the file and "2" is the character on that line that the definition starts with. If it fails
+to match this pattern (or the script fails to execute for some reason) the GraphQL schema will be opened as a fallback.
+
+This option requires >15.0.0 of the Relay compiler to function.
+
 ## Features
 
 - IntelliSense

vscode-extension/package.json

@@ -1,7 +1,7 @@
 {
   "name": "relay",
   "displayName": "Relay GraphQL",
-  "version": "2.0.0",
+  "version": "2.1.0",
   "description": "Relay-powered IDE experience",
   "repository": {
     "type": "git",
@@ -68,6 +68,15 @@
           ],
           "description": "Controls what is logged to the Output Channel for the Relay language server."
         },
+        "relay.pathToLocateCommand": {
+          "scope": "workspace",
+          "default": null,
+          "type": [
+            "string",
+            "null"
+          ],
+          "description": "Path to an optional script to look up the actual definition for a GraphQL entity for implementation-first GraphQL schemas."
+        },
         "relay.pathToRelay": {
           "scope": "workspace",
           "default": null,

vscode-extension/src/config.ts

@@ -11,6 +11,7 @@ export type Config = {
   rootDirectory: string | null;
   pathToRelay: string | null;
   pathToConfig: string | null;
+  pathToLocateCommand: string | null;
   lspOutputLevel: string;
   compilerOutpuLevel: string;
   autoStartCompiler: boolean;
@@ -22,6 +23,7 @@ export function getConfig(scope?: ConfigurationScope): Config {
   return {
     pathToRelay: configuration.get('pathToRelay') ?? null,
     pathToConfig: configuration.get('pathToConfig') ?? null,
+    pathToLocateCommand: configuration.get('pathToLocateCommand') ?? null,
     lspOutputLevel: configuration.get('lspOutputLevel') ?? 'quiet-with-errros',
     compilerOutpuLevel: configuration.get('compilerOutputLevel') ?? 'info',
     rootDirectory: configuration.get('rootDirectory') ?? null,

vscode-extension/src/languageClient.ts

@@ -30,6 +30,10 @@ export function createAndStartLanguageClient(context: RelayExtensionContext) {
     args.push(config.pathToConfig);
   }
 
+  if (config.pathToLocateCommand) {
+    args.push(`--locateCommand=${config.pathToLocateCommand}`);
+  }
+
   const serverOptions: ServerOptions = {
     options: {
       cwd: context.relayBinaryExecutionOptions.rootPath,