Allow Underscores in Project Names (#1209)

lib/scala/pkg/src/main/scala/org/enso/pkg/Package.scala

@@ -302,6 +302,47 @@ class PackageManager[F](implicit val fileSystem: FileSystem[F]) {
     existing.getOrElse(create(root, generateName(root)))
   }
 
+  /**
+    * Checks if a character is allowed in a project name.
+    *
+    * @param char the char to validate
+    * @return `true` if it's allowed, `false` otherwise
+    */
+  private def isAllowedNameCharacter(char: Char): Boolean = {
+    char.isLetterOrDigit || char == '_'
+  }
+
+  /**
+    * Takes a name containing letters, digits, and `_` characters and makes it
+    * a proper `Upper_Snake_Case` name.
+    *
+    * @param string the input string
+    * @return the transformed string
+    */
+  private def toUpperSnakeCase(string: String): String = {
+    val beginMarker = '#'
+    val chars       = string.toList
+    val charPairs   = (beginMarker :: chars).zip(chars)
+    charPairs
+      .map {
+        case (previous, current) =>
+          if (previous == beginMarker) {
+            current.toString
+          } else if (previous.isLower && current.isUpper) {
+            s"_$current"
+          } else if (previous.isLetter && current.isDigit) {
+            s"_$current"
+          } else if (previous == '_' && current == '_') {
+            ""
+          } else if (previous.isDigit && current.isLetter) {
+            s"_${current.toUpper}"
+          } else {
+            current.toString
+          }
+      }
+      .mkString("")
+  }
+
   /**
     * Transforms the given string into a valid package name (i.e. a CamelCased identifier).
     *
@@ -310,10 +351,10 @@ class PackageManager[F](implicit val fileSystem: FileSystem[F]) {
     */
   def normalizeName(name: String): String = {
     val startingWithLetter =
-      if (name.length == 0 || !name(0).isLetter) "Project" ++ name else name
+      if (name.length == 0 || !name(0).isLetter) "Project_" ++ name else name
     val startingWithUppercase = startingWithLetter.capitalize
-    val onlyAlphanumeric      = startingWithUppercase.filter(_.isLetterOrDigit)
-    onlyAlphanumeric
+    val onlyAlphanumeric      = startingWithUppercase.filter(isAllowedNameCharacter)
+    toUpperSnakeCase(onlyAlphanumeric)
   }
 
   /**

lib/scala/pkg/src/test/scala/org/enso/pkg/NameSanitizationSpec.scala

@@ -0,0 +1,23 @@
+package org.enso.pkg
+
+import java.io.File
+
+import org.enso.filesystem.FileSystem
+import org.scalatest.matchers.should.Matchers
+import org.scalatest.wordspec.AnyWordSpec
+
+class NameSanitizationSpec extends AnyWordSpec with Matchers {
+  "Creating a new project" should {
+    "sanitize the name of the project" in {
+      implicit val fileSystem: FileSystem[File] = FileSystem.Default
+
+      val manager = new PackageManager()
+
+      manager.normalizeName("My_Project") shouldEqual "My_Project"
+      manager.normalizeName("My___Project") shouldEqual "My_Project"
+      manager.normalizeName("myProject") shouldEqual "My_Project"
+      manager.normalizeName("myPro??^ject123") shouldEqual "My_Project_123"
+      manager.normalizeName("???%$6543lib") shouldEqual "Project_6543_Lib"
+    }
+  }
+}