Improve YamlError ADT

By providing the `ParseError` the original information that caused the error, an end user can use it for better diagnostics down the line.
VirtusLab · Mar 13, 2024 · 8a4d9f6 · 8a4d9f6
1 parent 71dba91
commit 8a4d9f6
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Showing 3 changed files with 49 additions and 6 deletions.
diff --git a/core/shared/src/main/scala/org/virtuslab/yaml/YamlError.scala b/core/shared/src/main/scala/org/virtuslab/yaml/YamlError.scala
@@ -5,6 +5,7 @@ import scala.util.control.NoStackTrace
 
 import org.virtuslab.yaml.internal.load.reader.token.Token
 import org.virtuslab.yaml.internal.load.reader.token.TokenKind
+import org.virtuslab.yaml.internal.load.TagValue
 
 /**
  * An ADT representing a decoding failure.
@@ -13,14 +14,21 @@ sealed trait YamlError {
   def msg: String
 }
 
-final case class ParseError(msg: String) extends YamlError
+sealed trait ParseError extends YamlError
 object ParseError {
-  def from(expected: String, got: Token): ParseError = ParseError(
-    s"""|Expected 
+  def from(expected: String, got: Token): ParseError    = ExpectedTokenKind(expected, got)
+  def from(expected: TokenKind, got: Token): ParseError = ParseError.from(expected.toString, got)
+
+  final case class ExpectedTokenKind(expected: String, got: Token) extends ParseError {
+    def msg: String =
+      s"""|Expected 
         |$expected but instead got ${got.kind}
         |${got.range.errorMsg}""".stripMargin
-  )
-  def from(expected: TokenKind, got: Token): ParseError = ParseError.from(expected.toString, got)
+  }
+
+  final case class NoRegisteredTagDirective(handleKey: String, tokenTag: Token) extends ParseError {
+    def msg: String = s"There is no registered tag directive for handle $handleKey"
+  }
 }
 
 final case class ComposerError(msg: String) extends YamlError

diff --git a/core/shared/src/main/scala/org/virtuslab/yaml/internal/load/parse/ParserImpl.scala b/core/shared/src/main/scala/org/virtuslab/yaml/internal/load/parse/ParserImpl.scala
@@ -456,7 +456,7 @@ final class ParserImpl private (in: Tokenizer) extends Parser {
                     else CustomTag(tagValue)
                   parseNodeAttributes(in.peekToken(), metadata.withTag(tag))
                 case None =>
-                  Left(ParseError(s"There is no registered tag directive for handle $handleKey"))
+                  Left(ParseError.NoRegisteredTagDirective(handleKey, token))
               }
           }
         case _ => Right(metadata, token)

diff --git a/core/shared/src/test/scala/org/virtuslab/yaml/parser/ParserSuite.scala b/core/shared/src/test/scala/org/virtuslab/yaml/parser/ParserSuite.scala
@@ -3,6 +3,9 @@ package parser
 
 import org.virtuslab.yaml.internal.load.parse.EventKind._
 import org.virtuslab.yaml.internal.load.reader.token.ScalarStyle
+import org.virtuslab.yaml.StringOps
+import org.virtuslab.yaml.internal.load.reader.token.Token
+import org.virtuslab.yaml.internal.load.reader.token.TokenKind.MappingKey
 
 class ParserSuite extends BaseYamlSuite {
 
@@ -89,4 +92,36 @@ class ParserSuite extends BaseYamlSuite {
 
     assertEquals(yaml.events, Right(expectedEvents))
   }
+
+  test("Parsing error") {
+    val errorMessage = """Expected 
+                         |BlockEnd but instead got MappingKey
+                         |  -- zipcode: 12-345
+                         |             ^""".stripMargin
+
+    val yaml =
+      """name: John Wick
+        |age: 40
+        |address:
+        |  - city: Anywhere
+        |  -- zipcode: 12-345
+        |""".stripMargin
+
+    val yamlLines = yaml.split("\n", -1).toVector
+
+    assertEquals(
+      yaml.asNode,
+      Left(
+        ParseError.ExpectedTokenKind(
+          "BlockEnd",
+          Token(
+            MappingKey,
+            Range(Position(65, 4, 13), yamlLines, None)
+          )
+        )
+      )
+    )
+
+    assertEquals(yaml.asNode.left.map(_.msg), Left(errorMessage))
+  }
 }