Relay Support in Rust Compiler (vercel#33702)

Reverts vercel#33699

This re-opens the support for relay in swc, although we need to narrow in the causes for the build failures in https://github.com/vercel/next.js/runs/4950448889?check_suite_focus=true

Co-authored-by: Andrey Lunyov <102968+alunyov@users.noreply.github.com>

docs/advanced-features/compiler.md

@@ -94,6 +94,26 @@ const customJestConfig = {
 module.exports = createJestConfig(customJestConfig)
 ```
 
+### Relay
+
+To enable [Relay](https://relay.dev/) support:
+
+```js
+// next.config.js
+module.exports = {
+  experimental: {
+    relay: {
+      // This should match relay.config.js
+      src: './',
+      artifactDirectory: './__generated__'
+      language: 'typescript',
+    },
+  },
+}
+```
+
+NOTE: In Next.js all JavaScripts files in `pages` directory are considered routes. So, for `relay-compiler` you'll need to specify `artifactDirectory` configuration settings outside of the `pages`, otherwise `relay-compiler` will generate files next to the source file in the `__generated__` directory, and this file will be considered a route, which will break production build.
+
 ### Remove React Properties
 
 Allows to remove JSX properties. This is often used for testing. Similar to `babel-plugin-react-remove-properties`.

package.json

@@ -60,6 +60,7 @@
     "@types/http-proxy": "1.17.3",
     "@types/jest": "24.0.13",
     "@types/node": "13.11.0",
+    "@types/relay-runtime": "13.0.0",
     "@types/selenium-webdriver": "4.0.15",
     "@types/sharp": "0.29.3",
     "@types/string-hash": "1.1.1",
@@ -147,6 +148,8 @@
     "react-dom": "17.0.2",
     "react-dom-18": "npm:react-dom@18.0.0-rc.0",
     "react-ssr-prepass": "1.0.8",
+    "relay-compiler": "13.0.2",
+    "relay-runtime": "13.0.2",
     "react-virtualized": "9.22.3",
     "release": "6.3.0",
     "request-promise-core": "1.1.2",

packages/next-swc/crates/core/Cargo.toml

@@ -8,6 +8,7 @@ crate-type = ["cdylib", "rlib"]
 
 [dependencies]
 chrono = "0.4"
+once_cell = "1.8.0"
 easy-error = "1.0.0"
 either = "1"
 fxhash = "0.2.1"
@@ -30,5 +31,3 @@ regex = "1.5"
 swc_ecma_transforms_testing = "0.59.0"
 testing = "0.18.0"
 walkdir = "2.3.2"
-
-

packages/next-swc/crates/core/src/lib.rs

@@ -53,6 +53,8 @@ pub mod next_dynamic;
 pub mod next_ssg;
 pub mod page_config;
 pub mod react_remove_properties;
+#[cfg(not(target_arch = "wasm32"))]
+pub mod relay;
 pub mod remove_console;
 pub mod shake_exports;
 pub mod styled_jsx;
@@ -91,6 +93,10 @@ pub struct TransformOptions {
     #[serde(default)]
     pub react_remove_properties: Option<react_remove_properties::Config>,
 
+    #[serde(default)]
+    #[cfg(not(target_arch = "wasm32"))]
+    pub relay: Option<relay::Config>,
+
     #[serde(default)]
     pub shake_exports: Option<shake_exports::Config>,
 }
@@ -99,7 +105,19 @@ pub fn custom_before_pass(
     cm: Arc<SourceMap>,
     file: Arc<SourceFile>,
     opts: &TransformOptions,
-) -> impl Fold {
+) -> impl Fold + '_ {
+    #[cfg(target_arch = "wasm32")]
+    let relay_plugin = noop();
+
+    #[cfg(not(target_arch = "wasm32"))]
+    let relay_plugin = {
+        if let Some(config) = &opts.relay {
+            Either::Left(relay::relay(config, file.name.clone()))
+        } else {
+            Either::Right(noop())
+        }
+    };
+
     chain!(
         disallow_re_export_all_in_page::disallow_re_export_all_in_page(opts.is_page_file),
         styled_jsx::styled_jsx(cm.clone()),
@@ -130,6 +148,7 @@ pub fn custom_before_pass(
             page_config::page_config(opts.is_development, opts.is_page_file),
             !opts.disable_page_config
         ),
+        relay_plugin,
         match &opts.remove_console {
             Some(config) if config.truthy() =>
                 Either::Left(remove_console::remove_console(config.clone())),

packages/next-swc/crates/core/src/relay.rs

@@ -0,0 +1,170 @@
+use once_cell::sync::Lazy;
+use regex::Regex;
+use serde::Deserialize;
+use std::path::{Path, PathBuf};
+use swc_atoms::JsWord;
+use swc_common::errors::HANDLER;
+use swc_common::FileName;
+use swc_ecmascript::ast::*;
+use swc_ecmascript::utils::{quote_ident, ExprFactory};
+use swc_ecmascript::visit::{Fold, FoldWith};
+
+#[derive(Copy, Clone, Debug, Deserialize)]
+#[serde(rename_all = "lowercase")]
+pub enum RelayLanguageConfig {
+    TypeScript,
+    Flow,
+}
+
+impl Default for RelayLanguageConfig {
+    fn default() -> Self {
+        Self::Flow
+    }
+}
+
+struct Relay<'a> {
+    root_dir: PathBuf,
+    file_name: FileName,
+    config: &'a Config,
+}
+
+#[derive(Deserialize, Debug, Default, Clone)]
+#[serde(rename_all = "camelCase")]
+pub struct Config {
+    pub src: PathBuf,
+    pub artifact_directory: Option<PathBuf>,
+    #[serde(default)]
+    pub language: RelayLanguageConfig,
+}
+
+fn pull_first_operation_name_from_tpl(tpl: &TaggedTpl) -> Option<String> {
+    tpl.tpl.quasis.iter().find_map(|quasis| {
+        static OPERATION_REGEX: Lazy<Regex> =
+            Lazy::new(|| Regex::new(r"(fragment|mutation|query|subscription) (\w+)").unwrap());
+
+        let capture_group = OPERATION_REGEX.captures_iter(&quasis.raw.value).next();
+
+        capture_group.map(|capture_group| capture_group[2].to_string())
+    })
+}
+
+fn build_require_expr_from_path(path: &str) -> Expr {
+    Expr::Call(CallExpr {
+        span: Default::default(),
+        callee: quote_ident!("require").as_callee(),
+        args: vec![
+            Lit::Str(Str {
+                span: Default::default(),
+                value: JsWord::from(path),
+                has_escape: false,
+                kind: Default::default(),
+            })
+            .as_arg(),
+        ],
+        type_args: None,
+    })
+}
+
+impl<'a> Fold for Relay<'a> {
+    fn fold_expr(&mut self, expr: Expr) -> Expr {
+        let expr = expr.fold_children_with(self);
+
+        match &expr {
+            Expr::TaggedTpl(tpl) => {
+                if let Some(built_expr) = self.build_call_expr_from_tpl(tpl) {
+                    built_expr
+                } else {
+                    expr
+                }
+            }
+            _ => expr,
+        }
+    }
+}
+
+#[derive(Debug)]
+enum BuildRequirePathError {
+    FileNameNotReal,
+    ArtifactDirectoryExpected,
+}
+
+fn path_for_artifact(
+    root_dir: &Path,
+    config: &Config,
+    definition_name: &str,
+) -> Result<PathBuf, BuildRequirePathError> {
+    let filename = match &config.language {
+        RelayLanguageConfig::Flow => format!("{}.graphql.js", definition_name),
+        RelayLanguageConfig::TypeScript => {
+            format!("{}.graphql.ts", definition_name)
+        }
+    };
+
+    if let Some(artifact_directory) = &config.artifact_directory {
+        Ok(root_dir.join(artifact_directory).join(filename))
+    } else {
+        Err(BuildRequirePathError::ArtifactDirectoryExpected)
+    }
+}
+
+impl<'a> Relay<'a> {
+    fn build_require_path(
+        &mut self,
+        operation_name: &str,
+    ) -> Result<PathBuf, BuildRequirePathError> {
+        match &self.file_name {
+            FileName::Real(_real_file_name) => {
+                path_for_artifact(&self.root_dir, self.config, operation_name)
+            }
+            _ => Err(BuildRequirePathError::FileNameNotReal),
+        }
+    }
+
+    fn build_call_expr_from_tpl(&mut self, tpl: &TaggedTpl) -> Option<Expr> {
+        if let Expr::Ident(ident) = &*tpl.tag {
+            if &*ident.sym != "graphql" {
+                return None;
+            }
+        }
+
+        let operation_name = pull_first_operation_name_from_tpl(tpl);
+
+        match operation_name {
+            None => None,
+            Some(operation_name) => match self.build_require_path(operation_name.as_str()) {
+                Ok(final_path) => Some(build_require_expr_from_path(final_path.to_str().unwrap())),
+                Err(err) => {
+                    let base_error = "Could not transform GraphQL template to a Relay import.";
+                    let error_message = match err {
+                        BuildRequirePathError::FileNameNotReal => "Source file was not a real \
+                                                                   file. This is likely a bug and \
+                                                                   should be reported to Next.js"
+                            .to_string(),
+                        BuildRequirePathError::ArtifactDirectoryExpected => {
+                            "The `artifactDirectory` is expected to be set in the Relay config \
+                             file to work correctly with Next.js."
+                                .to_string()
+                        }
+                    };
+
+                    HANDLER.with(|handler| {
+                        handler.span_err(
+                            tpl.span,
+                            format!("{} {}", base_error, error_message).as_str(),
+                        );
+                    });
+
+                    None
+                }
+            },
+        }
+    }
+}
+
+pub fn relay<'a>(config: &'a Config, file_name: FileName) -> impl Fold + '_ {
+    Relay {
+        root_dir: std::env::current_dir().unwrap(),
+        file_name,
+        config,
+    }
+}

packages/next-swc/crates/core/tests/fixture.rs

@@ -4,6 +4,7 @@ use next_swc::{
     next_ssg::next_ssg,
     page_config::page_config_test,
     react_remove_properties::remove_properties,
+    relay::{relay, Config as RelayConfig, RelayLanguageConfig},
     remove_console::remove_console,
     shake_exports::{shake_exports, Config as ShakeExportsConfig},
     styled_jsx::styled_jsx,
@@ -149,6 +150,22 @@ fn page_config_fixture(input: PathBuf) {
     test_fixture(syntax(), &|_tr| page_config_test(), &input, &output);
 }
 
+#[fixture("tests/fixture/relay/**/input.ts*")]
+fn relay_no_artifact_dir_fixture(input: PathBuf) {
+    let output = input.parent().unwrap().join("output.js");
+    let config = RelayConfig {
+        language: RelayLanguageConfig::TypeScript,
+        artifact_directory: Some(PathBuf::from("__generated__")),
+        ..Default::default()
+    };
+    test_fixture(
+        syntax(),
+        &|_tr| relay(&config, FileName::Real(PathBuf::from("input.tsx"))),
+        &input,
+        &output,
+    );
+}
+
 #[fixture("tests/fixture/remove-console/**/input.js")]
 fn remove_console_fixture(input: PathBuf) {
     let output = input.parent().unwrap().join("output.js");

packages/next-swc/crates/core/tests/fixture/relay/input.tsx

@@ -0,0 +1,42 @@
+const variableQuery = graphql`
+  query InputVariableQuery {
+    hello
+  }
+`
+
+fetchQuery(graphql`
+  query InputUsedInFunctionCallQuery {
+    hello
+  }
+`)
+
+function SomeQueryComponent() {
+  useLazyLoadQuery(graphql`
+    query InputInHookQuery {
+      hello
+    }
+  `)
+}
+
+const variableMutation = graphql`
+  query InputVariableMutation {
+    someMutation
+  }
+`
+
+commitMutation(
+    environment,
+    graphql`
+      query InputUsedInFunctionCallMutation {
+        someMutation
+      }
+    `
+)
+
+function SomeMutationComponent() {
+  useMutation(graphql`
+    query InputInHookMutation {
+      someMutation
+    }
+  `)
+}

packages/next-swc/crates/core/tests/fixture/relay/output.js

@@ -0,0 +1,10 @@
+const variableQuery = require("$DIR/__generated__/InputVariableQuery.graphql.ts");
+fetchQuery(require("$DIR/__generated__/InputUsedInFunctionCallQuery.graphql.ts"));
+function SomeQueryComponent() {
+    useLazyLoadQuery(require("$DIR/__generated__/InputInHookQuery.graphql.ts"));
+}
+const variableMutation = require("$DIR/__generated__/InputVariableMutation.graphql.ts");
+commitMutation(environment, require("$DIR/__generated__/InputUsedInFunctionCallMutation.graphql.ts"));
+function SomeMutationComponent() {
+    useMutation(require("$DIR/__generated__/InputInHookMutation.graphql.ts"));
+}

packages/next-swc/crates/core/tests/full.rs

@@ -59,6 +59,7 @@ fn test(input: &Path, minify: bool) {
                 styled_components: Some(assert_json("{}")),
                 remove_console: None,
                 react_remove_properties: None,
+                relay: None,
                 shake_exports: None,
             };
 

packages/next/build/swc/options.js

@@ -83,6 +83,7 @@ export function getBaseSWCOptions({
       : null,
     removeConsole: nextConfig?.experimental?.removeConsole,
     reactRemoveProperties: nextConfig?.experimental?.reactRemoveProperties,
+    relay: nextConfig?.experimental?.relay,
   }
 }
 

packages/next/build/webpack-config.ts

@@ -1621,6 +1621,7 @@ export default async function getBaseWebpackConfig(
     removeConsole: config.experimental.removeConsole,
     reactRemoveProperties: config.experimental.reactRemoveProperties,
     styledComponents: config.experimental.styledComponents,
+    relay: config.experimental.relay,
   })
 
   const cache: any = {