fix(install): support installing npm package with alias (#26246)

Just tried this out today and it wasn't properly implemented in
https://github.com/denoland/deno/pull/24156

cli/tools/registry/pm.rs

@@ -363,7 +363,14 @@ fn package_json_dependency_entry(
   selected: SelectedPackage,
 ) -> (String, String) {
   if let Some(npm_package) = selected.package_name.strip_prefix("npm:") {
-    (npm_package.into(), selected.version_req)
+    if selected.import_name == npm_package {
+      (npm_package.into(), selected.version_req)
+    } else {
+      (
+        selected.import_name,
+        format!("npm:{}@{}", npm_package, selected.version_req),
+      )
+    }
   } else if let Some(jsr_package) = selected.package_name.strip_prefix("jsr:") {
     let jsr_package = jsr_package.strip_prefix('@').unwrap_or(jsr_package);
     let scope_replaced = jsr_package.replace('/', "__");
@@ -741,6 +748,9 @@ fn generate_imports(mut packages_to_version: Vec<(String, String)>) -> String {
   let mut contents = vec![];
   let len = packages_to_version.len();
   for (index, (package, version)) in packages_to_version.iter().enumerate() {
+    if index == 0 {
+      contents.push(String::new()); // force a newline at the start
+    }
     // TODO(bartlomieju): fix it, once we start support specifying version on the cli
     contents.push(format!("\"{}\": \"{}\"", package, version));
     if index != len - 1 {

tests/specs/add/alias/__test__.jsonc

@@ -0,0 +1,13 @@
+{
+  "tempDir": true,
+  "steps": [{
+    "args": "install my-alias@npm:@denotest/add",
+    "output": "[WILDCARD]"
+  }, {
+    "args": [
+      "eval",
+      "console.log(Deno.readTextFileSync('package.json').trim())"
+    ],
+    "output": "package.json.out"
+  }]
+}

tests/specs/add/alias/package.json

@@ -0,0 +1,4 @@
+{
+  "dependencies": {
+  }
+}

tests/specs/add/alias/package.json.out

@@ -0,0 +1,5 @@
+{
+  "dependencies": {
+    "my-alias": "npm:@denotest/add@^1.0.0"
+  }
+}

tests/specs/add/dev/package.json.out

@@ -1,3 +1,5 @@
 {
-  "devDependencies": { "@denotest/esm-basic": "^1.0.0" }
+  "devDependencies": {
+    "@denotest/esm-basic": "^1.0.0"
+  }
 }

tests/specs/install/future_install_local_add_npm/package.json.out

@@ -1,3 +1,5 @@
 {
-  "dependencies": { "@denotest/esm-basic": "^1.0.0" }
+  "dependencies": {
+    "@denotest/esm-basic": "^1.0.0"
+  }
 }

tests/specs/install/install_add_dev/package.json.out

@@ -1,3 +1,5 @@
 {
-  "devDependencies": { "@denotest/esm-basic": "^1.0.0" }
+  "devDependencies": {
+    "@denotest/esm-basic": "^1.0.0"
+  }
 }

tests/specs/install/install_deprecated_package/package.json.out

@@ -1,3 +1,5 @@
 {
-  "dependencies": { "@denotest/deprecated-package": "^1.0.0" }
+  "dependencies": {
+    "@denotest/deprecated-package": "^1.0.0"
+  }
 }

tests/specs/remove/package_json/rm_add_package.json.out

@@ -1,3 +1,5 @@
 {
-  "devDependencies": { "@denotest/esm-basic": "^1.0.0" }
+  "devDependencies": {
+    "@denotest/esm-basic": "^1.0.0"
+  }
 }