Merge pull request #3439 from square/bquenaudon.2025-10-16.ProtocolException

oldergod · web-flow · commit c55326b854dc · 2025-10-17T12:37:53.000+01:00
Improve ProtocolException's message
diff --git a/wire-runtime/src/commonMain/kotlin/com/squareup/wire/ByteArrayProtoReader32.kt b/wire-runtime/src/commonMain/kotlin/com/squareup/wire/ByteArrayProtoReader32.kt
@@ -129,7 +129,7 @@ internal class ByteArrayProtoReader32(
     nextFieldEncoding = FieldEncoding.LENGTH_DELIMITED
     state = STATE_LENGTH_DELIMITED
     val length = internalReadVarint32()
-    if (length < 0) throw ProtocolException("Negative length: $length")
+    if (length < 0) throw ProtocolException("Negative length: $length. Reader position: $pos. Last read tag: $tag.")
     if (pushedLimit != -1) throw IllegalStateException()
     // Push the current limit, and set a new limit to the length of this value.
     pushedLimit = limit
@@ -148,7 +148,7 @@ internal class ByteArrayProtoReader32(
 
     loop@ while (pos < limit) {
       val tagAndFieldEncoding = internalReadVarint32()
-      if (tagAndFieldEncoding == 0) throw ProtocolException("Unexpected tag 0")
+      if (tagAndFieldEncoding == 0) throw ProtocolException("Unexpected tag 0. Reader position: $pos. Last read tag: $tag.")
 
       tag = tagAndFieldEncoding shr TAG_FIELD_ENCODING_BITS
       when (val groupOrFieldEncoding = tagAndFieldEncoding and FIELD_ENCODING_MASK) {
@@ -157,7 +157,7 @@ internal class ByteArrayProtoReader32(
           continue@loop
         }
 
-        STATE_END_GROUP -> throw ProtocolException("Unexpected end group")
+        STATE_END_GROUP -> throw ProtocolException("Unexpected end group. Reader position: $pos. Last read tag: $tag.")
 
         STATE_LENGTH_DELIMITED -> {
           internalNextLengthDelimited()
@@ -182,7 +182,7 @@ internal class ByteArrayProtoReader32(
           return tag
         }
 
-        else -> throw ProtocolException("Unexpected field encoding: $groupOrFieldEncoding")
+        else -> throw ProtocolException("Unexpected field encoding: $groupOrFieldEncoding. Reader position: $pos. Last read tag: $tag.")
       }
     }
     return -1
@@ -207,7 +207,7 @@ internal class ByteArrayProtoReader32(
   private fun skipGroup(expectedEndTag: Int) {
     while (pos < limit) {
       val tagAndFieldEncoding = internalReadVarint32()
-      if (tagAndFieldEncoding == 0) throw ProtocolException("Unexpected tag 0")
+      if (tagAndFieldEncoding == 0) throw ProtocolException("Unexpected tag 0. Reader position: $pos. Last read tag: $tag.")
       val tag = tagAndFieldEncoding shr TAG_FIELD_ENCODING_BITS
       when (val groupOrFieldEncoding = tagAndFieldEncoding and FIELD_ENCODING_MASK) {
         STATE_START_GROUP -> {
@@ -224,7 +224,7 @@ internal class ByteArrayProtoReader32(
         }
         STATE_END_GROUP -> {
           if (tag == expectedEndTag) return // Success!
-          throw ProtocolException("Unexpected end group")
+          throw ProtocolException("Unexpected end group. Reader position: $pos. Last read tag: $tag.")
         }
         STATE_LENGTH_DELIMITED -> {
           val length = internalReadVarint32()
@@ -242,7 +242,7 @@ internal class ByteArrayProtoReader32(
           state = STATE_FIXED32
           readFixed32()
         }
-        else -> throw ProtocolException("Unexpected field encoding: $groupOrFieldEncoding")
+        else -> throw ProtocolException("Unexpected field encoding: $groupOrFieldEncoding. Reader position: $pos. Last read tag: $tag.")
       }
     }
     throw EOFException()
@@ -272,7 +272,7 @@ internal class ByteArrayProtoReader32(
       STATE_FIXED32,
       -> true // Not packed.
 
-      else -> throw ProtocolException("unexpected state: $state")
+      else -> throw ProtocolException("unexpected state: $state. Reader position: $pos. Last read tag: $tag.")
     }
   }
 
@@ -283,7 +283,7 @@ internal class ByteArrayProtoReader32(
 
   override fun readVarint32(): Int {
     if (state != STATE_VARINT && state != STATE_LENGTH_DELIMITED) {
-      throw ProtocolException("Expected VARINT or LENGTH_DELIMITED but was $state")
+      throw ProtocolException("Expected VARINT or LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")
     }
     val result = internalReadVarint32()
     afterPackableScalar(STATE_VARINT)
@@ -320,7 +320,7 @@ internal class ByteArrayProtoReader32(
                 return result
               }
             }
-            throw ProtocolException("Malformed VARINT")
+            throw ProtocolException("Malformed VARINT. Reader position: $pos. Last read tag: $tag.")
           }
         }
       }
@@ -330,7 +330,7 @@ internal class ByteArrayProtoReader32(
 
   override fun readVarint64(): Long {
     if (state != STATE_VARINT && state != STATE_LENGTH_DELIMITED) {
-      throw ProtocolException("Expected VARINT or LENGTH_DELIMITED but was $state")
+      throw ProtocolException("Expected VARINT or LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")
     }
     var shift = 0
     var result: Long = 0
@@ -343,12 +343,12 @@ internal class ByteArrayProtoReader32(
       }
       shift += 7
     }
-    throw ProtocolException("WireInput encountered a malformed varint")
+    throw ProtocolException("WireInput encountered a malformed varint. Reader position: $pos. Last read tag: $tag.")
   }
 
   override fun readFixed32(): Int {
     if (state != STATE_FIXED32 && state != STATE_LENGTH_DELIMITED) {
-      throw ProtocolException("Expected FIXED32 or LENGTH_DELIMITED but was $state")
+      throw ProtocolException("Expected FIXED32 or LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")
     }
     val result = readIntLe()
     afterPackableScalar(STATE_FIXED32)
@@ -357,7 +357,7 @@ internal class ByteArrayProtoReader32(
 
   override fun readFixed64(): Long {
     if (state != STATE_FIXED64 && state != STATE_LENGTH_DELIMITED) {
-      throw ProtocolException("Expected FIXED64 or LENGTH_DELIMITED but was $state")
+      throw ProtocolException("Expected FIXED64 or LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")
     }
     val result = readLongLe()
     afterPackableScalar(STATE_FIXED64)
@@ -383,7 +383,7 @@ internal class ByteArrayProtoReader32(
 
   private fun beforeLengthDelimitedScalar(): Int {
     if (state != STATE_LENGTH_DELIMITED) {
-      throw ProtocolException("Expected LENGTH_DELIMITED but was $state")
+      throw ProtocolException("Expected LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")
     }
     val byteCount = limit - pos
     state = STATE_TAG
diff --git a/wire-runtime/src/commonMain/kotlin/com/squareup/wire/ProtoReader.kt b/wire-runtime/src/commonMain/kotlin/com/squareup/wire/ProtoReader.kt
@@ -154,7 +154,7 @@ open class ProtoReader(private val source: BufferedSource) {
     nextFieldEncoding = FieldEncoding.LENGTH_DELIMITED
     state = STATE_LENGTH_DELIMITED
     val length = internalReadVarint32()
-    if (length < 0) throw ProtocolException("Negative length: $length")
+    if (length < 0) throw ProtocolException("Negative length: $length. Reader position: $pos. Last read tag: $tag.")
     if (pushedLimit != -1L) throw IllegalStateException()
     // Push the current limit, and set a new limit to the length of this value.
     pushedLimit = limit
@@ -179,7 +179,7 @@ open class ProtoReader(private val source: BufferedSource) {
 
     loop@ while (pos < limit && !source.exhausted()) {
       val tagAndFieldEncoding = internalReadVarint32()
-      if (tagAndFieldEncoding == 0) throw ProtocolException("Unexpected tag 0")
+      if (tagAndFieldEncoding == 0) throw ProtocolException("Unexpected tag 0. Reader position: $pos. Last read tag: $tag.")
 
       tag = tagAndFieldEncoding shr TAG_FIELD_ENCODING_BITS
       when (val groupOrFieldEncoding = tagAndFieldEncoding and FIELD_ENCODING_MASK) {
@@ -188,7 +188,7 @@ open class ProtoReader(private val source: BufferedSource) {
           continue@loop
         }
 
-        STATE_END_GROUP -> throw ProtocolException("Unexpected end group")
+        STATE_END_GROUP -> throw ProtocolException("Unexpected end group. Reader position: $pos. Last read tag: $tag.")
 
         STATE_LENGTH_DELIMITED -> {
           internalNextLengthDelimited()
@@ -213,7 +213,7 @@ open class ProtoReader(private val source: BufferedSource) {
           return tag
         }
 
-        else -> throw ProtocolException("Unexpected field encoding: $groupOrFieldEncoding")
+        else -> throw ProtocolException("Unexpected field encoding: $groupOrFieldEncoding. Reader position: $pos. Last read tag: $tag.")
       }
     }
     return -1
@@ -246,7 +246,7 @@ open class ProtoReader(private val source: BufferedSource) {
   private fun skipGroup(expectedEndTag: Int) {
     while (pos < limit && !source.exhausted()) {
       val tagAndFieldEncoding = internalReadVarint32()
-      if (tagAndFieldEncoding == 0) throw ProtocolException("Unexpected tag 0")
+      if (tagAndFieldEncoding == 0) throw ProtocolException("Unexpected tag 0. Reader position: $pos. Last read tag: $tag.")
       val tag = tagAndFieldEncoding shr TAG_FIELD_ENCODING_BITS
       when (val groupOrFieldEncoding = tagAndFieldEncoding and FIELD_ENCODING_MASK) {
         STATE_START_GROUP -> {
@@ -263,7 +263,7 @@ open class ProtoReader(private val source: BufferedSource) {
         }
         STATE_END_GROUP -> {
           if (tag == expectedEndTag) return // Success!
-          throw ProtocolException("Unexpected end group")
+          throw ProtocolException("Unexpected end group. Reader position: $pos. Last read tag: $tag.")
         }
         STATE_LENGTH_DELIMITED -> {
           val length = internalReadVarint32()
@@ -282,7 +282,7 @@ open class ProtoReader(private val source: BufferedSource) {
           state = STATE_FIXED32
           readFixed32()
         }
-        else -> throw ProtocolException("Unexpected field encoding: $groupOrFieldEncoding")
+        else -> throw ProtocolException("Unexpected field encoding: $groupOrFieldEncoding. Reader position: $pos. Last read tag: $tag.")
       }
     }
     throw EOFException()
@@ -322,7 +322,7 @@ open class ProtoReader(private val source: BufferedSource) {
       STATE_FIXED32,
       -> true // Not packed.
 
-      else -> throw ProtocolException("unexpected state: $state")
+      else -> throw ProtocolException("unexpected state: $state. Reader position: $pos. Last read tag: $tag.")
     }
   }
 
@@ -340,7 +340,7 @@ open class ProtoReader(private val source: BufferedSource) {
   @Throws(IOException::class)
   open fun readVarint32(): Int {
     if (state != STATE_VARINT && state != STATE_LENGTH_DELIMITED) {
-      throw ProtocolException("Expected VARINT or LENGTH_DELIMITED but was $state")
+      throw ProtocolException("Expected VARINT or LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")
     }
     val result = internalReadVarint32()
     afterPackableScalar(STATE_VARINT)
@@ -389,7 +389,7 @@ open class ProtoReader(private val source: BufferedSource) {
                 return result
               }
             }
-            throw ProtocolException("Malformed VARINT")
+            throw ProtocolException("Malformed VARINT. Reader position: $pos. Last read tag: $tag.")
           }
         }
       }
@@ -401,7 +401,7 @@ open class ProtoReader(private val source: BufferedSource) {
   @Throws(IOException::class)
   open fun readVarint64(): Long {
     if (state != STATE_VARINT && state != STATE_LENGTH_DELIMITED) {
-      throw ProtocolException("Expected VARINT or LENGTH_DELIMITED but was $state")
+      throw ProtocolException("Expected VARINT or LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")
     }
     var shift = 0
     var result: Long = 0
@@ -416,14 +416,14 @@ open class ProtoReader(private val source: BufferedSource) {
       }
       shift += 7
     }
-    throw ProtocolException("WireInput encountered a malformed varint")
+    throw ProtocolException("Malformed VARINT. Reader position: $pos. Last read tag: $tag.")
   }
 
   /** Reads a 32-bit little-endian integer from the stream.  */
   @Throws(IOException::class)
   open fun readFixed32(): Int {
     if (state != STATE_FIXED32 && state != STATE_LENGTH_DELIMITED) {
-      throw ProtocolException("Expected FIXED32 or LENGTH_DELIMITED but was $state")
+      throw ProtocolException("Expected FIXED32 or LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")
     }
     source.require(4) // Throws EOFException if insufficient bytes are available.
     pos += 4
@@ -436,7 +436,7 @@ open class ProtoReader(private val source: BufferedSource) {
   @Throws(IOException::class)
   open fun readFixed64(): Long {
     if (state != STATE_FIXED64 && state != STATE_LENGTH_DELIMITED) {
-      throw ProtocolException("Expected FIXED64 or LENGTH_DELIMITED but was $state")
+      throw ProtocolException("Expected FIXED64 or LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")
     }
     source.require(8) // Throws EOFException if insufficient bytes are available.
     pos += 8
@@ -466,7 +466,7 @@ open class ProtoReader(private val source: BufferedSource) {
   @Throws(IOException::class)
   private fun beforeLengthDelimitedScalar(): Long {
     if (state != STATE_LENGTH_DELIMITED) {
-      throw ProtocolException("Expected LENGTH_DELIMITED but was $state")
+      throw ProtocolException("Expected LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")
     }
     val byteCount = limit - pos
     source.require(byteCount) // Throws EOFException if insufficient bytes are available.
diff --git a/wire-schema/src/jvmTest/kotlin/com/squareup/wire/schema/SchemaProtoAdapterTest.kt b/wire-schema/src/jvmTest/kotlin/com/squareup/wire/schema/SchemaProtoAdapterTest.kt
@@ -172,7 +172,7 @@ class SchemaProtoAdapterTest {
       adapter.decode(Buffer().write(encoded))
       fail()
     } catch (expected: ProtocolException) {
-      assertThat(expected).hasMessage("Unexpected end group")
+      assertThat(expected).hasMessage("Unexpected end group. Reader position: 4. Last read tag: 3.")
     }
   }
 
@@ -194,7 +194,7 @@ class SchemaProtoAdapterTest {
       adapter.decode(Buffer().write(encoded))
       fail()
     } catch (expected: ProtocolException) {
-      assertThat(expected).hasMessage("Unexpected end group")
+      assertThat(expected).hasMessage("Unexpected end group. Reader position: 5. Last read tag: 3.")
     }
   }
 
diff --git a/wire-tests/src/commonTest/kotlin/com/squareup/wire/ParseTest.kt b/wire-tests/src/commonTest/kotlin/com/squareup/wire/ParseTest.kt
@@ -51,7 +51,7 @@ class ParseTest {
       OneField.ADAPTER.decode(data.toByteArray())
       fail()
     } catch (expected: ProtocolException) {
-      assertThat(expected).hasMessage("Unexpected field encoding: 7")
+      assertThat(expected).hasMessage("Unexpected field encoding: 7. Reader position: 4. Last read tag: 2.")
     }
   }
 
diff --git a/wire-tests/src/jvmJavaTest/java/com/squareup/wire/ParseTest.java b/wire-tests/src/jvmJavaTest/java/com/squareup/wire/ParseTest.java
@@ -49,7 +49,9 @@ public void unknownTypeThrowsIOException() throws Exception {
       OneField.ADAPTER.decode(data.toByteArray());
       fail();
     } catch (ProtocolException expected) {
-      assertThat(expected).hasMessageThat().contains("Unexpected field encoding: 7");
+      assertThat(expected)
+          .hasMessageThat()
+          .contains("Unexpected field encoding: 7. Reader position: 4. Last read tag: 2.");
     }
   }
 

Original file line number	Diff line number	Diff line change
`@@ -129,7 +129,7 @@ internal class ByteArrayProtoReader32(`
`129`	`129`	`nextFieldEncoding = FieldEncoding.LENGTH_DELIMITED`
`130`	`130`	`state = STATE_LENGTH_DELIMITED`
`131`	`131`	`val length = internalReadVarint32()`
`132`		`- if (length < 0) throw ProtocolException("Negative length: $length")`
	`132`	`+ if (length < 0) throw ProtocolException("Negative length: $length. Reader position: $pos. Last read tag: $tag.")`
`133`	`133`	`if (pushedLimit != -1) throw IllegalStateException()`
`134`	`134`	`// Push the current limit, and set a new limit to the length of this value.`
`135`	`135`	`pushedLimit = limit`
`@@ -148,7 +148,7 @@ internal class ByteArrayProtoReader32(`
`148`	`148`
`149`	`149`	`loop@ while (pos < limit) {`
`150`	`150`	`val tagAndFieldEncoding = internalReadVarint32()`
`151`		`- if (tagAndFieldEncoding == 0) throw ProtocolException("Unexpected tag 0")`
	`151`	`+ if (tagAndFieldEncoding == 0) throw ProtocolException("Unexpected tag 0. Reader position: $pos. Last read tag: $tag.")`
`152`	`152`
`153`	`153`	`tag = tagAndFieldEncoding shr TAG_FIELD_ENCODING_BITS`
`154`	`154`	`when (val groupOrFieldEncoding = tagAndFieldEncoding and FIELD_ENCODING_MASK) {`
`@@ -157,7 +157,7 @@ internal class ByteArrayProtoReader32(`
`157`	`157`	`continue@loop`
`158`	`158`	`}`
`159`	`159`
`160`		`- STATE_END_GROUP -> throw ProtocolException("Unexpected end group")`
	`160`	`+ STATE_END_GROUP -> throw ProtocolException("Unexpected end group. Reader position: $pos. Last read tag: $tag.")`
`161`	`161`
`162`	`162`	`STATE_LENGTH_DELIMITED -> {`
`163`	`163`	`internalNextLengthDelimited()`
`@@ -182,7 +182,7 @@ internal class ByteArrayProtoReader32(`
`182`	`182`	`return tag`
`183`	`183`	`}`
`184`	`184`
`185`		`- else -> throw ProtocolException("Unexpected field encoding: $groupOrFieldEncoding")`
	`185`	`+ else -> throw ProtocolException("Unexpected field encoding: $groupOrFieldEncoding. Reader position: $pos. Last read tag: $tag.")`
`186`	`186`	`}`
`187`	`187`	`}`
`188`	`188`	`return -1`
`@@ -207,7 +207,7 @@ internal class ByteArrayProtoReader32(`
`207`	`207`	`private fun skipGroup(expectedEndTag: Int) {`
`208`	`208`	`while (pos < limit) {`
`209`	`209`	`val tagAndFieldEncoding = internalReadVarint32()`
`210`		`- if (tagAndFieldEncoding == 0) throw ProtocolException("Unexpected tag 0")`
	`210`	`+ if (tagAndFieldEncoding == 0) throw ProtocolException("Unexpected tag 0. Reader position: $pos. Last read tag: $tag.")`
`211`	`211`	`val tag = tagAndFieldEncoding shr TAG_FIELD_ENCODING_BITS`
`212`	`212`	`when (val groupOrFieldEncoding = tagAndFieldEncoding and FIELD_ENCODING_MASK) {`
`213`	`213`	`STATE_START_GROUP -> {`
`@@ -224,7 +224,7 @@ internal class ByteArrayProtoReader32(`
`224`	`224`	`}`
`225`	`225`	`STATE_END_GROUP -> {`
`226`	`226`	`if (tag == expectedEndTag) return // Success!`
`227`		`- throw ProtocolException("Unexpected end group")`
	`227`	`+ throw ProtocolException("Unexpected end group. Reader position: $pos. Last read tag: $tag.")`
`228`	`228`	`}`
`229`	`229`	`STATE_LENGTH_DELIMITED -> {`
`230`	`230`	`val length = internalReadVarint32()`
`@@ -242,7 +242,7 @@ internal class ByteArrayProtoReader32(`
`242`	`242`	`state = STATE_FIXED32`
`243`	`243`	`readFixed32()`
`244`	`244`	`}`
`245`		`- else -> throw ProtocolException("Unexpected field encoding: $groupOrFieldEncoding")`
	`245`	`+ else -> throw ProtocolException("Unexpected field encoding: $groupOrFieldEncoding. Reader position: $pos. Last read tag: $tag.")`
`246`	`246`	`}`
`247`	`247`	`}`
`248`	`248`	`throw EOFException()`
`@@ -272,7 +272,7 @@ internal class ByteArrayProtoReader32(`
`272`	`272`	`STATE_FIXED32,`
`273`	`273`	`-> true // Not packed.`
`274`	`274`
`275`		`- else -> throw ProtocolException("unexpected state: $state")`
	`275`	`+ else -> throw ProtocolException("unexpected state: $state. Reader position: $pos. Last read tag: $tag.")`
`276`	`276`	`}`
`277`	`277`	`}`
`278`	`278`
`@@ -283,7 +283,7 @@ internal class ByteArrayProtoReader32(`
`283`	`283`
`284`	`284`	`override fun readVarint32(): Int {`
`285`	`285`	`if (state != STATE_VARINT && state != STATE_LENGTH_DELIMITED) {`
`286`		`- throw ProtocolException("Expected VARINT or LENGTH_DELIMITED but was $state")`
	`286`	`+ throw ProtocolException("Expected VARINT or LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")`
`287`	`287`	`}`
`288`	`288`	`val result = internalReadVarint32()`
`289`	`289`	`afterPackableScalar(STATE_VARINT)`
`@@ -320,7 +320,7 @@ internal class ByteArrayProtoReader32(`
`320`	`320`	`return result`
`321`	`321`	`}`
`322`	`322`	`}`
`323`		`- throw ProtocolException("Malformed VARINT")`
	`323`	`+ throw ProtocolException("Malformed VARINT. Reader position: $pos. Last read tag: $tag.")`
`324`	`324`	`}`
`325`	`325`	`}`
`326`	`326`	`}`
`@@ -330,7 +330,7 @@ internal class ByteArrayProtoReader32(`
`330`	`330`
`331`	`331`	`override fun readVarint64(): Long {`
`332`	`332`	`if (state != STATE_VARINT && state != STATE_LENGTH_DELIMITED) {`
`333`		`- throw ProtocolException("Expected VARINT or LENGTH_DELIMITED but was $state")`
	`333`	`+ throw ProtocolException("Expected VARINT or LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")`
`334`	`334`	`}`
`335`	`335`	`var shift = 0`
`336`	`336`	`var result: Long = 0`
`@@ -343,12 +343,12 @@ internal class ByteArrayProtoReader32(`
`343`	`343`	`}`
`344`	`344`	`shift += 7`
`345`	`345`	`}`
`346`		`- throw ProtocolException("WireInput encountered a malformed varint")`
	`346`	`+ throw ProtocolException("WireInput encountered a malformed varint. Reader position: $pos. Last read tag: $tag.")`
`347`	`347`	`}`
`348`	`348`
`349`	`349`	`override fun readFixed32(): Int {`
`350`	`350`	`if (state != STATE_FIXED32 && state != STATE_LENGTH_DELIMITED) {`
`351`		`- throw ProtocolException("Expected FIXED32 or LENGTH_DELIMITED but was $state")`
	`351`	`+ throw ProtocolException("Expected FIXED32 or LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")`
`352`	`352`	`}`
`353`	`353`	`val result = readIntLe()`
`354`	`354`	`afterPackableScalar(STATE_FIXED32)`
`@@ -357,7 +357,7 @@ internal class ByteArrayProtoReader32(`
`357`	`357`
`358`	`358`	`override fun readFixed64(): Long {`
`359`	`359`	`if (state != STATE_FIXED64 && state != STATE_LENGTH_DELIMITED) {`
`360`		`- throw ProtocolException("Expected FIXED64 or LENGTH_DELIMITED but was $state")`
	`360`	`+ throw ProtocolException("Expected FIXED64 or LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")`
`361`	`361`	`}`
`362`	`362`	`val result = readLongLe()`
`363`	`363`	`afterPackableScalar(STATE_FIXED64)`
`@@ -383,7 +383,7 @@ internal class ByteArrayProtoReader32(`
`383`	`383`
`384`	`384`	`private fun beforeLengthDelimitedScalar(): Int {`
`385`	`385`	`if (state != STATE_LENGTH_DELIMITED) {`
`386`		`- throw ProtocolException("Expected LENGTH_DELIMITED but was $state")`
	`386`	`+ throw ProtocolException("Expected LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")`
`387`	`387`	`}`
`388`	`388`	`val byteCount = limit - pos`
`389`	`389`	`state = STATE_TAG`
Original file line number	Diff line number	Diff line change
`@@ -154,7 +154,7 @@ open class ProtoReader(private val source: BufferedSource) {`
`154`	`154`	`nextFieldEncoding = FieldEncoding.LENGTH_DELIMITED`
`155`	`155`	`state = STATE_LENGTH_DELIMITED`
`156`	`156`	`val length = internalReadVarint32()`
`157`		`- if (length < 0) throw ProtocolException("Negative length: $length")`
	`157`	`+ if (length < 0) throw ProtocolException("Negative length: $length. Reader position: $pos. Last read tag: $tag.")`
`158`	`158`	`if (pushedLimit != -1L) throw IllegalStateException()`
`159`	`159`	`// Push the current limit, and set a new limit to the length of this value.`
`160`	`160`	`pushedLimit = limit`
`@@ -179,7 +179,7 @@ open class ProtoReader(private val source: BufferedSource) {`
`179`	`179`
`180`	`180`	`loop@ while (pos < limit && !source.exhausted()) {`
`181`	`181`	`val tagAndFieldEncoding = internalReadVarint32()`
`182`		`- if (tagAndFieldEncoding == 0) throw ProtocolException("Unexpected tag 0")`
	`182`	`+ if (tagAndFieldEncoding == 0) throw ProtocolException("Unexpected tag 0. Reader position: $pos. Last read tag: $tag.")`
`183`	`183`
`184`	`184`	`tag = tagAndFieldEncoding shr TAG_FIELD_ENCODING_BITS`
`185`	`185`	`when (val groupOrFieldEncoding = tagAndFieldEncoding and FIELD_ENCODING_MASK) {`
`@@ -188,7 +188,7 @@ open class ProtoReader(private val source: BufferedSource) {`
`188`	`188`	`continue@loop`
`189`	`189`	`}`
`190`	`190`
`191`		`- STATE_END_GROUP -> throw ProtocolException("Unexpected end group")`
	`191`	`+ STATE_END_GROUP -> throw ProtocolException("Unexpected end group. Reader position: $pos. Last read tag: $tag.")`
`192`	`192`
`193`	`193`	`STATE_LENGTH_DELIMITED -> {`
`194`	`194`	`internalNextLengthDelimited()`
`@@ -213,7 +213,7 @@ open class ProtoReader(private val source: BufferedSource) {`
`213`	`213`	`return tag`
`214`	`214`	`}`
`215`	`215`
`216`		`- else -> throw ProtocolException("Unexpected field encoding: $groupOrFieldEncoding")`
	`216`	`+ else -> throw ProtocolException("Unexpected field encoding: $groupOrFieldEncoding. Reader position: $pos. Last read tag: $tag.")`
`217`	`217`	`}`
`218`	`218`	`}`
`219`	`219`	`return -1`
`@@ -246,7 +246,7 @@ open class ProtoReader(private val source: BufferedSource) {`
`246`	`246`	`private fun skipGroup(expectedEndTag: Int) {`
`247`	`247`	`while (pos < limit && !source.exhausted()) {`
`248`	`248`	`val tagAndFieldEncoding = internalReadVarint32()`
`249`		`- if (tagAndFieldEncoding == 0) throw ProtocolException("Unexpected tag 0")`
	`249`	`+ if (tagAndFieldEncoding == 0) throw ProtocolException("Unexpected tag 0. Reader position: $pos. Last read tag: $tag.")`
`250`	`250`	`val tag = tagAndFieldEncoding shr TAG_FIELD_ENCODING_BITS`
`251`	`251`	`when (val groupOrFieldEncoding = tagAndFieldEncoding and FIELD_ENCODING_MASK) {`
`252`	`252`	`STATE_START_GROUP -> {`
`@@ -263,7 +263,7 @@ open class ProtoReader(private val source: BufferedSource) {`
`263`	`263`	`}`
`264`	`264`	`STATE_END_GROUP -> {`
`265`	`265`	`if (tag == expectedEndTag) return // Success!`
`266`		`- throw ProtocolException("Unexpected end group")`
	`266`	`+ throw ProtocolException("Unexpected end group. Reader position: $pos. Last read tag: $tag.")`
`267`	`267`	`}`
`268`	`268`	`STATE_LENGTH_DELIMITED -> {`
`269`	`269`	`val length = internalReadVarint32()`
`@@ -282,7 +282,7 @@ open class ProtoReader(private val source: BufferedSource) {`
`282`	`282`	`state = STATE_FIXED32`
`283`	`283`	`readFixed32()`
`284`	`284`	`}`
`285`		`- else -> throw ProtocolException("Unexpected field encoding: $groupOrFieldEncoding")`
	`285`	`+ else -> throw ProtocolException("Unexpected field encoding: $groupOrFieldEncoding. Reader position: $pos. Last read tag: $tag.")`
`286`	`286`	`}`
`287`	`287`	`}`
`288`	`288`	`throw EOFException()`
`@@ -322,7 +322,7 @@ open class ProtoReader(private val source: BufferedSource) {`
`322`	`322`	`STATE_FIXED32,`
`323`	`323`	`-> true // Not packed.`
`324`	`324`
`325`		`- else -> throw ProtocolException("unexpected state: $state")`
	`325`	`+ else -> throw ProtocolException("unexpected state: $state. Reader position: $pos. Last read tag: $tag.")`
`326`	`326`	`}`
`327`	`327`	`}`
`328`	`328`
`@@ -340,7 +340,7 @@ open class ProtoReader(private val source: BufferedSource) {`
`340`	`340`	`@Throws(IOException::class)`
`341`	`341`	`open fun readVarint32(): Int {`
`342`	`342`	`if (state != STATE_VARINT && state != STATE_LENGTH_DELIMITED) {`
`343`		`- throw ProtocolException("Expected VARINT or LENGTH_DELIMITED but was $state")`
	`343`	`+ throw ProtocolException("Expected VARINT or LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")`
`344`	`344`	`}`
`345`	`345`	`val result = internalReadVarint32()`
`346`	`346`	`afterPackableScalar(STATE_VARINT)`
`@@ -389,7 +389,7 @@ open class ProtoReader(private val source: BufferedSource) {`
`389`	`389`	`return result`
`390`	`390`	`}`
`391`	`391`	`}`
`392`		`- throw ProtocolException("Malformed VARINT")`
	`392`	`+ throw ProtocolException("Malformed VARINT. Reader position: $pos. Last read tag: $tag.")`
`393`	`393`	`}`
`394`	`394`	`}`
`395`	`395`	`}`
`@@ -401,7 +401,7 @@ open class ProtoReader(private val source: BufferedSource) {`
`401`	`401`	`@Throws(IOException::class)`
`402`	`402`	`open fun readVarint64(): Long {`
`403`	`403`	`if (state != STATE_VARINT && state != STATE_LENGTH_DELIMITED) {`
`404`		`- throw ProtocolException("Expected VARINT or LENGTH_DELIMITED but was $state")`
	`404`	`+ throw ProtocolException("Expected VARINT or LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")`
`405`	`405`	`}`
`406`	`406`	`var shift = 0`
`407`	`407`	`var result: Long = 0`
`@@ -416,14 +416,14 @@ open class ProtoReader(private val source: BufferedSource) {`
`416`	`416`	`}`
`417`	`417`	`shift += 7`
`418`	`418`	`}`
`419`		`- throw ProtocolException("WireInput encountered a malformed varint")`
	`419`	`+ throw ProtocolException("Malformed VARINT. Reader position: $pos. Last read tag: $tag.")`
`420`	`420`	`}`
`421`	`421`
`422`	`422`	`/** Reads a 32-bit little-endian integer from the stream. */`
`423`	`423`	`@Throws(IOException::class)`
`424`	`424`	`open fun readFixed32(): Int {`
`425`	`425`	`if (state != STATE_FIXED32 && state != STATE_LENGTH_DELIMITED) {`
`426`		`- throw ProtocolException("Expected FIXED32 or LENGTH_DELIMITED but was $state")`
	`426`	`+ throw ProtocolException("Expected FIXED32 or LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")`
`427`	`427`	`}`
`428`	`428`	`source.require(4) // Throws EOFException if insufficient bytes are available.`
`429`	`429`	`pos += 4`
`@@ -436,7 +436,7 @@ open class ProtoReader(private val source: BufferedSource) {`
`436`	`436`	`@Throws(IOException::class)`
`437`	`437`	`open fun readFixed64(): Long {`
`438`	`438`	`if (state != STATE_FIXED64 && state != STATE_LENGTH_DELIMITED) {`
`439`		`- throw ProtocolException("Expected FIXED64 or LENGTH_DELIMITED but was $state")`
	`439`	`+ throw ProtocolException("Expected FIXED64 or LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")`
`440`	`440`	`}`
`441`	`441`	`source.require(8) // Throws EOFException if insufficient bytes are available.`
`442`	`442`	`pos += 8`
`@@ -466,7 +466,7 @@ open class ProtoReader(private val source: BufferedSource) {`
`466`	`466`	`@Throws(IOException::class)`
`467`	`467`	`private fun beforeLengthDelimitedScalar(): Long {`
`468`	`468`	`if (state != STATE_LENGTH_DELIMITED) {`
`469`		`- throw ProtocolException("Expected LENGTH_DELIMITED but was $state")`
	`469`	`+ throw ProtocolException("Expected LENGTH_DELIMITED but was $state. Reader position: $pos. Last read tag: $tag.")`
`470`	`470`	`}`
`471`	`471`	`val byteCount = limit - pos`
`472`	`472`	`source.require(byteCount) // Throws EOFException if insufficient bytes are available.`
Original file line number	Diff line number	Diff line change
`@@ -172,7 +172,7 @@ class SchemaProtoAdapterTest {`
`172`	`172`	`adapter.decode(Buffer().write(encoded))`
`173`	`173`	`fail()`
`174`	`174`	`} catch (expected: ProtocolException) {`
`175`		`- assertThat(expected).hasMessage("Unexpected end group")`
	`175`	`+ assertThat(expected).hasMessage("Unexpected end group. Reader position: 4. Last read tag: 3.")`
`176`	`176`	`}`
`177`	`177`	`}`
`178`	`178`
`@@ -194,7 +194,7 @@ class SchemaProtoAdapterTest {`
`194`	`194`	`adapter.decode(Buffer().write(encoded))`
`195`	`195`	`fail()`
`196`	`196`	`} catch (expected: ProtocolException) {`
`197`		`- assertThat(expected).hasMessage("Unexpected end group")`
	`197`	`+ assertThat(expected).hasMessage("Unexpected end group. Reader position: 5. Last read tag: 3.")`
`198`	`198`	`}`
`199`	`199`	`}`
`200`	`200`
Original file line number	Diff line number	Diff line change
`@@ -51,7 +51,7 @@ class ParseTest {`
`51`	`51`	`OneField.ADAPTER.decode(data.toByteArray())`
`52`	`52`	`fail()`
`53`	`53`	`} catch (expected: ProtocolException) {`
`54`		`- assertThat(expected).hasMessage("Unexpected field encoding: 7")`
	`54`	`+ assertThat(expected).hasMessage("Unexpected field encoding: 7. Reader position: 4. Last read tag: 2.")`
`55`	`55`	`}`
`56`	`56`	`}`
`57`	`57`
Original file line number	Diff line number	Diff line change
`@@ -49,7 +49,9 @@ public void unknownTypeThrowsIOException() throws Exception {`
`49`	`49`	`OneField.ADAPTER.decode(data.toByteArray());`
`50`	`50`	`fail();`
`51`	`51`	`} catch (ProtocolException expected) {`
`52`		`- assertThat(expected).hasMessageThat().contains("Unexpected field encoding: 7");`
	`52`	`+ assertThat(expected)`
	`53`	`+ .hasMessageThat()`
	`54`	`+ .contains("Unexpected field encoding: 7. Reader position: 4. Last read tag: 2.");`
`53`	`55`	`}`
`54`	`56`	`}`
`55`	`57`