Rewatch: warn about deprecated package specs es6/es6-global

Author: cknitt

rewatch/src/build.rs

@@ -428,6 +428,12 @@ fn log_config_warnings(build_state: &BuildCommandState) {
                     config::DeprecationWarning::BscFlags => {
                         log_deprecated_config_field(&package.name, "bsc-flags", "compiler-flags");
                     }
+                    config::DeprecationWarning::PackageSpecsEs6 => {
+                        log_deprecated_package_specs_module("es6");
+                    }
+                    config::DeprecationWarning::PackageSpecsEs6Global => {
+                        log_deprecated_package_specs_module("es6-global");
+                    }
                 },
             );
 
@@ -454,6 +460,11 @@ fn log_deprecated_config_field(package_name: &str, field_name: &str, new_field_n
     println!("\n{}", style(warning).yellow());
 }
 
+fn log_deprecated_package_specs_module(module_name: &str) {
+    let warning = format!("deprecated: Option \"{module_name}\" is deprecated. Use \"esmodule\" instead.");
+    println!("\n{}", style(warning).yellow());
+}
+
 fn log_unsupported_config_field(package_name: &str, field_name: &str) {
     let warning = format!(
         "The field '{field_name}' found in the package config of '{package_name}' is not supported by ReScript 12's new build system."

rewatch/src/config.rs

@@ -224,6 +224,8 @@ pub enum DeprecationWarning {
     BsDependencies,
     BsDevDependencies,
     BscFlags,
+    PackageSpecsEs6,
+    PackageSpecsEs6Global,
 }
 
 #[derive(Debug, Clone, Eq, PartialEq, Hash)]
@@ -746,6 +748,23 @@ impl Config {
             self.deprecation_warnings.push(DeprecationWarning::BscFlags);
         }
 
+        let (has_es6, has_es6_global) = match &self.package_specs {
+            None => (false, false),
+            Some(OneOrMore::Single(spec)) => (spec.module == "es6", spec.module == "es6-global"),
+            Some(OneOrMore::Multiple(specs)) => (
+                specs.iter().any(|spec| spec.module == "es6"),
+                specs.iter().any(|spec| spec.module == "es6-global"),
+            ),
+        };
+        if has_es6 {
+            self.deprecation_warnings
+                .push(DeprecationWarning::PackageSpecsEs6);
+        }
+        if has_es6_global {
+            self.deprecation_warnings
+                .push(DeprecationWarning::PackageSpecsEs6Global);
+        }
+
         Ok(())
     }
 }
@@ -1081,6 +1100,55 @@ pub mod tests {
         assert!(config.get_deprecations().is_empty());
     }
 
+    #[test]
+    fn test_package_specs_es6_global_deprecation() {
+        let json = r#"
+        {
+            "name": "testrepo",
+            "sources": {
+                "dir": "src",
+                "subdirs": true
+            },
+            "package-specs": [
+                {
+                "module": "es6-global",
+                "in-source": true
+                }
+            ],
+            "suffix": ".mjs"
+        }
+        "#;
+
+        let config = Config::new_from_json_string(json).expect("a valid json string");
+        assert_eq!(
+            config.get_deprecations(),
+            [DeprecationWarning::PackageSpecsEs6Global]
+        );
+    }
+
+    #[test]
+    fn test_package_specs_es6_deprecation() {
+        let json = r#"
+        {
+            "name": "testrepo",
+            "sources": {
+                "dir": "src",
+                "subdirs": true
+            },
+            "package-specs": [
+                {
+                "module": "es6",
+                "in-source": true
+                }
+            ],
+            "suffix": ".mjs"
+        }
+        "#;
+
+        let config = Config::new_from_json_string(json).expect("a valid json string");
+        assert_eq!(config.get_deprecations(), [DeprecationWarning::PackageSpecsEs6]);
+    }
+
     #[test]
     fn test_unknown_fields_are_collected() {
         let json = r#"

tests/build_tests/deprecated-package-specs/input.js

@@ -3,10 +3,13 @@
 import assert from "node:assert";
 import { setup } from "#dev/process";
 
-const { execBuildLegacy } = setup(import.meta.dirname);
+const { execBuild, execClean } = setup(import.meta.dirname);
+
+const { stdout } = await execBuild();
 
-const out = await execBuildLegacy();
 assert.match(
-  out.stderr,
+  stdout,
   /deprecated: Option "es6-global" is deprecated\. Use "esmodule" instead\./,
 );
+
+await execClean();

tests/build_tests/deprecated-package-specs/src/Index.res

@@ -1 +1 @@
-let () = Js.log("Hello, ReScript")
+let () = Console.log("Hello, ReScript")