yarn2 is not supported

Author: mikrostew

crates/volta-core/src/error/kind.rs

@@ -499,6 +499,9 @@ pub enum ErrorKind {
     #[cfg(windows)]
     WriteUserPathError,
 
+    /// Thrown when a user attempts to install a version of Yarn2
+    Yarn2NotSupported,
+
     /// Thrown when there is an error fetching the latest version of Yarn
     YarnLatestFetchError {
         from_url: String,
@@ -1373,6 +1376,12 @@ to {}
                 "Could not write Path environment variable.
 
 Please ensure you have permissions to edit your environment variables."
+            ),
+            ErrorKind::Yarn2NotSupported => write!(
+                f,
+                "Yarn@2 is not recommended for use, and not supported by Volta.
+
+Please use Yarn@3 instead."
             ),
             ErrorKind::YarnLatestFetchError { from_url } => write!(
                 f,
@@ -1506,6 +1515,7 @@ impl ErrorKind {
             ErrorKind::WritePlatformError { .. } => ExitCode::FileSystemError,
             #[cfg(windows)]
             ErrorKind::WriteUserPathError => ExitCode::EnvironmentError,
+            ErrorKind::Yarn2NotSupported => ExitCode::NoVersionMatch,
             ErrorKind::YarnLatestFetchError { .. } => ExitCode::NetworkError,
             ErrorKind::YarnVersionNotFound { .. } => ExitCode::NoVersionMatch,
         }

crates/volta-core/src/tool/yarn/fetch.rs

@@ -127,7 +127,7 @@ fn determine_remote_url(version: &Version, hooks: Option<&ToolHooks<Yarn>>) -> F
             hook.resolve(version, &distro_file_name)
         }
         _ => {
-            let matches_yarn_berry = VersionReq::parse(">2").unwrap();
+            let matches_yarn_berry = VersionReq::parse(">=2").unwrap();
             if env::var_os("VOLTA_FEATURE_YARN_3").is_some() && matches_yarn_berry.matches(version)
             {
                 Ok(public_registry_package(

crates/volta-core/src/tool/yarn/resolve.rs

@@ -119,26 +119,35 @@ fn resolve_semver_from_registry(matching: VersionReq) -> Fallible<Version> {
     if env::var_os("VOLTA_FEATURE_YARN_3").is_some() {
         // first try yarn2+, which uses "@yarnpkg/cli-dist" instead of "yarn"
         let (url, index) = fetch_yarn_index("@yarnpkg/cli-dist")?;
-        let details_opt = index
+        let matching_entries: Vec<PackageDetails> = index
             .entries
             .into_iter()
-            .find(|PackageDetails { version, .. }| matching.matches(version));
-
-        match details_opt {
-            Some(details) => {
-                debug!(
-                    "Found yarn@{} matching requirement '{}' from {}",
-                    details.version, matching, url
-                );
-                return Ok(details.version);
-            }
-            None => {
-                debug!(
-                    "Did not find yarn matching requirement '{}' from {}",
-                    matching, url
-                );
+            .filter(|PackageDetails { version, .. }| matching.matches(version))
+            .collect();
+
+        if matching_entries.len() > 0 {
+            let matches_yarn_3 = VersionReq::parse(">=3").unwrap();
+            let details_opt = matching_entries
+                .iter()
+                .find(|PackageDetails { version, .. }| matches_yarn_3.matches(version));
+
+            match details_opt {
+                Some(details) => {
+                    debug!(
+                        "Found yarn@{} matching requirement '{}' from {}",
+                        details.version, matching, url
+                    );
+                    return Ok(details.version.clone());
+                }
+                None => {
+                    return Err(ErrorKind::Yarn2NotSupported.into());
+                }
             }
         }
+        debug!(
+            "Did not find yarn matching requirement '{}' from {}",
+            matching, url
+        );
     }
 
     let (url, index) = fetch_yarn_index("yarn")?;

tests/acceptance/volta_pin.rs

@@ -411,7 +411,6 @@ fn pin_yarn_1() {
 
 #[test]
 fn pin_yarn_2_is_error() {
-    // TODO
     let s = sandbox()
         .package_json(&package_json_with_pinned_node("1.2.3"))
         .yarn_1_available_versions(YARN_1_VERSION_INFO)
@@ -423,12 +422,16 @@ fn pin_yarn_2_is_error() {
 
     assert_that!(
         s.volta("pin yarn@2"),
-        execs().with_status(ExitCode::Success as i32)
+        execs()
+            .with_status(ExitCode::NoVersionMatch as i32)
+            .with_stderr_contains(
+                "[..]Yarn@2 is not recommended for use, and not supported by Volta[..]"
+            )
     );
 
     assert_eq!(
         s.read_package_json(),
-        package_json_with_pinned_node_yarn("1.2.3", "2.4.159"),
+        package_json_with_pinned_node("1.2.3"),
     )
 }