Crash while compiling Yarn file

[OhTerryTorres]

A particular Yarn file causes a compilation error.

Error on line 6 at position 10:
no viable alternative at input '<<set $s1.'
<<set $s1.pirateRespect to 0>>
..........^

The node in question looks like this:

title: S1
tags: 
colorID: 0
position: 337,-9941
---
**<<set $s1_pirateRespect to 0>>**
<<set $s1_firstMate to "Kazuma">>
{$firstMate} takes the spyglass from his eye.
<<if Rapp()>>
    Rapp: Check it out.<p> Looks like we found something.
<<else>>
    Guido: Care to take a peek?
<<endif>>
{$firstMate} offers it to you.
...

Full Yarn file here.

The variable $s1_pirateRespect was changed from $s1.pirateRespect back when updating to YarnSpinner 1.0. So it appears to be... an old version of the file?

Reimporting triggers the following build errors, top to bottom:

NullReferenceException: Object reference not set to an instance of an object
Yarn.Compiler.BodyVisitor.GenerateFormattedText (System.Collections.Generic.IList`1[T] nodes, System.String& outputString, System.Int32& expressionCount) (at <9d419cb6180b453c97c5942b14e16443>:0)
Yarn.Compiler.BodyVisitor.VisitCommand_statement (YarnSpinnerParser+Command_statementContext context) (at <9d419cb6180b453c97c5942b14e16443>:0)
YarnSpinnerParser+Command_statementContext.Accept[TResult] (Antlr4.Runtime.Tree.IParseTreeVisitor`1[Result] visitor) (at <9d419cb6180b453c97c5942b14e16443>:0)
Antlr4.Runtime.Tree.AbstractParseTreeVisitor`1[Result].VisitChildren (Antlr4.Runtime.Tree.IRuleNode node) (at <f2f4188ed7484f8ca20ff6e9163f87df>:0)
YarnSpinnerParserBaseVisitor`1[Result].VisitStatement (YarnSpinnerParser+StatementContext context) (at <9d419cb6180b453c97c5942b14e16443>:0)
YarnSpinnerParser+StatementContext.Accept[TResult] (Antlr4.Runtime.Tree.IParseTreeVisitor`1[Result] visitor) (at <9d419cb6180b453c97c5942b14e16443>:0)
Antlr4.Runtime.Tree.AbstractParseTreeVisitor`1[Result].Visit (Antlr4.Runtime.Tree.IParseTree tree) (at <f2f4188ed7484f8ca20ff6e9163f87df>:0)
Yarn.Compiler.Compiler.EnterBody (YarnSpinnerParser+BodyContext context) (at <9d419cb6180b453c97c5942b14e16443>:0)
YarnSpinnerParser+BodyContext.EnterRule (Antlr4.Runtime.Tree.IParseTreeListener listener) (at <9d419cb6180b453c97c5942b14e16443>:0)
Antlr4.Runtime.Tree.ParseTreeWalker.EnterRule (Antlr4.Runtime.Tree.IParseTreeListener listener, Antlr4.Runtime.Tree.IRuleNode r) (at <f2f4188ed7484f8ca20ff6e9163f87df>:0)
Antlr4.Runtime.Tree.ParseTreeWalker.Walk (Antlr4.Runtime.Tree.IParseTreeListener listener, Antlr4.Runtime.Tree.IParseTree t) (at <f2f4188ed7484f8ca20ff6e9163f87df>:0)
Antlr4.Runtime.Tree.ParseTreeWalker.Walk (Antlr4.Runtime.Tree.IParseTreeListener listener, Antlr4.Runtime.Tree.IParseTree t) (at <f2f4188ed7484f8ca20ff6e9163f87df>:0)
Antlr4.Runtime.Tree.ParseTreeWalker.Walk (Antlr4.Runtime.Tree.IParseTreeListener listener, Antlr4.Runtime.Tree.IParseTree t) (at <f2f4188ed7484f8ca20ff6e9163f87df>:0)
Yarn.Compiler.Compiler.Compile (Antlr4.Runtime.Tree.IParseTree tree) (at <9d419cb6180b453c97c5942b14e16443>:0)
Yarn.Compiler.Compiler.CompileString (System.String text, System.String fileName, Yarn.Program& program, System.Collections.Generic.IDictionary`2[System.String,Yarn.Compiler.StringInfo]& stringTable) (at <9d419cb6180b453c97c5942b14e16443>:0)
YarnImporter.ImportYarn (UnityEditor.Experimental.AssetImporters.AssetImportContext ctx) (at Assets/YarnSpinner/Editor/YarnImporter.cs:71)
YarnImporter.OnImportAsset (UnityEditor.Experimental.AssetImporters.AssetImportContext ctx) (at Assets/YarnSpinner/Editor/YarnImporter.cs:54)
UnityEditor.Experimental.AssetImporters.ScriptedImporter.GenerateAssetData (UnityEditor.Experimental.AssetImporters.AssetImportContext ctx) (at /Users/builduser/buildslave/unity/build/Modules/AssetPipelineEditor/Public/ScriptedImporter.cs:22)


AssetImporter is referencing an asset from the previous import. This should not happen.


Asset import failed, "Assets/Resources/Dialogues/S1a.yarn" > NullReferenceException: Object reference not set to an instance of an object
Yarn.Compiler.BodyVisitor.GenerateFormattedText (System.Collections.Generic.IList`1[T] nodes, System.String& outputString, System.Int32& expressionCount) (at <9d419cb6180b453c97c5942b14e16443>:0)
Yarn.Compiler.BodyVisitor.VisitCommand_statement (YarnSpinnerParser+Command_statementContext context) (at <9d419cb6180b453c97c5942b14e16443>:0)
YarnSpinnerParser+Command_statementContext.Accept[TResult] (Antlr4.Runtime.Tree.IParseTreeVisitor`1[Result] visitor) (at <9d419cb6180b453c97c5942b14e16443>:0)
Antlr4.Runtime.Tree.AbstractParseTreeVisitor`1[Result].VisitChildren (Antlr4.Runtime.Tree.IRuleNode node) (at <f2f4188ed7484f8ca20ff6e9163f87df>:0)
YarnSpinnerParserBaseVisitor`1[Result].VisitStatement (YarnSpinnerParser+StatementContext context) (at <9d419cb6180b453c97c5942b14e16443>:0)
YarnSpinnerParser+StatementContext.Accept[TResult] (Antlr4.Runtime.Tree.IParseTreeVisitor`1[Result] visitor) (at <9d419cb6180b453c97c5942b14e16443>:0)
Antlr4.Runtime.Tree.AbstractParseTreeVisitor`1[Result].Visit (Antlr4.Runtime.Tree.IParseTree tree) (at <f2f4188ed7484f8ca20ff6e9163f87df>:0)
Yarn.Compiler.Compiler.EnterBody (YarnSpinnerParser+BodyContext context) (at <9d419cb6180b453c97c5942b14e16443>:0)
YarnSpinnerParser+BodyContext.EnterRule (Antlr4.Runtime.Tree.IParseTreeListener listener) (at <9d419cb6180b453c97c5942b14e16443>:0)
Antlr4.Runtime.Tree.ParseTreeWalker.EnterRule (Antlr4.Runtime.Tree.IParseTreeListener listener, Antlr4.Runtime.Tree.IRuleNode r) (at <f2f4188ed7484f8ca20ff6e9163f87df>:0)
Antlr4.Runtime.Tree.ParseTreeWalker.Walk (Antlr4.Runtime.Tree.IParseTreeListener listener, Antlr4.Runtime.Tree.IParseTree t) (at <f2f4188ed7484f8ca20ff6e9163f87df>:0)
Antlr4.Runtime.Tree.ParseTreeWalker.Walk (Antlr4.Runtime.Tree.IParseTreeListener listener, Antlr4.Runtime.Tree.IParseTree t) (at <f2f4188ed7484f8ca20ff6e9163f87df>:0)
Antlr4.Runtime.Tree.ParseTreeWalker.Walk (Antlr4.Runtime.Tree.IParseTreeListener listener, Antlr4.Runtime.Tree.IParseTree t) (at <f2f4188ed7484f8ca20ff6e9163f87df>:0)
Yarn.Compiler.Compiler.Compile (Antlr4.Runtime.Tree.IParseTree tree) (at <9d419cb6180b453c97c5942b14e16443>:0)
Yarn.Compiler.Compiler.CompileString (System.String text, System.String fileName, Yarn.Program& program, System.Collections.Generic.IDictionary`2[System.String,Yarn.Compiler.StringInfo]& stringTable) (at <9d419cb6180b453c97c5942b14e16443>:0)
YarnImporter.ImportYarn (UnityEditor.Experimental.AssetImporters.AssetImportContext ctx) (at Assets/YarnSpinner/Editor/YarnImporter.cs:71)
YarnImporter.OnImportAsset (UnityEditor.Experimental.AssetImporters.AssetImportContext ctx) (at Assets/YarnSpinner/Editor/YarnImporter.cs:54)
UnityEditor.Experimental.AssetImporters.ScriptedImporter.GenerateAssetData (UnityEditor.Experimental.AssetImporters.AssetImportContext ctx) (at /Users/builduser/buildslave/unity/build/Modules/AssetPipelineEditor/Public/ScriptedImporter.cs:22)

The error is resolved if approximately the first 34 nodes in the Yarn file are deleted.

Build warnings for all other Yarn files are accurate.

• Yarn Spinner Version: 1.1.0
• Unity Version: 2019.2.12f1

[desplesda]

Thank you for this report! Will investigate.

[desplesda]

Looks like the issue isn't actually in the node S1 in your file. In isolation, it compiles fine.

When I attempted to compile the full Yarn file you linked, I saw an exception when parsing the command <<p>> on line 386. (The same command also appears on line 1368.)

The issue is that commands that are a single character long (<<p>>) cause a crash in the compiler. As a workaround until a fix is shipped, replace the single-character command with something else (e.g. <pp>).

Technical details of the error!

It appears that <<p>> is being lexed as a COMMAND_START '<<', followed by a COMMAND_TEXT_END 'p>>'. This is incorrect behaviour from the lexer, because COMMAND_TEXT_END should only ever be >>.

It appears that the more directive in line 380 of YarnSpinnerLexer.g4 is causing the entire string p>> to be incorrectly matched against the token COMMAND_TEXT_END, when it should have been matched as a COMMAND_TEXT followed by a COMMAND_TEXT_END.

YarnSpinner/YarnSpinner.Compiler/YarnSpinnerLexer.g4

Line 380 in fdcf67c

COMMAND_ARBITRARY: . -> more, mode(CommandTextMode);

This can be fixed by marking the token as COMMAND_TEXT before moving to CommandTextMode:

COMMAND_ARBITRARY: . -> type(COMMAND_TEXT), mode(CommandTextMode);

I'll push a fix for this issue now, and it should be resolved in the next release.

Thanks for reporting this!