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Fix crash on Javadoc comments before package/import (#143) #155

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Merged
paulirwin merged 1 commit into from
Aug 14, 2026
Merged

Fix crash on Javadoc comments before package/import (#143) #155

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76 changes: 76 additions & 0 deletions JavaToCSharp.Tests/CommentTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -165,4 +165,80 @@ public virtual void Method1()

Assert.Equal(expected.ReplaceLineEndings(), parsed.ReplaceLineEndings());
}

[Fact]
public void JavadocBeforePackage_ShouldNotCrash()
{
const string javaCode = """
/**
* Some comments
*/
package foo;

import java.util.List;

public class Foo {
}
""";
var options = new JavaConversionOptions();
options.Usings.Clear();

var parsed = JavaToCSharpConverter.ConvertText(javaCode, options) ?? "";

testOutputHelper.WriteLine(parsed);

const string expected = """
/*
* Some comments
*/
using Java.Util;

namespace Foo
{
public class Foo
{
}
}
""";

Assert.Equal(expected.ReplaceLineEndings(), parsed.ReplaceLineEndings());
}

[Fact]
public void JavadocBeforeImport_ShouldNotCrash()
{
const string javaCode = """
package foo;

/**
* Import comment
*/
import java.util.List;

public class Foo {
}
""";
var options = new JavaConversionOptions();
options.Usings.Clear();

var parsed = JavaToCSharpConverter.ConvertText(javaCode, options) ?? "";

testOutputHelper.WriteLine(parsed);

const string expected = """
/*
* Import comment
*/
using Java.Util;

namespace Foo
{
public class Foo
{
}
}
""";

Assert.Equal(expected.ReplaceLineEndings(), parsed.ReplaceLineEndings());
}
}
53 changes: 44 additions & 9 deletions JavaToCSharp/CommentsHelper.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -42,9 +42,7 @@ public static UsingDirectiveSyntax AddUsingComments(UsingDirectiveSyntax syntax,

foreach (var (comment, _) in comments)
{
var (kind, pre, post) = GetCommentInfo(comment);
var commentTrivia = SyntaxFactory.SyntaxTrivia(kind, pre + comment.getContent() + post);
leadingTriviaList.Add(commentTrivia);
leadingTriviaList.Add(CreateNonMemberCommentTrivia(comment));
}

return syntax.WithUsingKeyword(SyntaxFactory.Token(SyntaxKind.UsingKeyword).WithLeadingTrivia(leadingTriviaList));
Expand All @@ -59,9 +57,7 @@ public static CompilationUnitSyntax AddPackageComments(CompilationUnitSyntax syn

if (compilationUnit.getComment().FromOptional<JavaComments.Comment>() is { } compilationUnitComment)
{
var (kind, pre, post) = GetCommentInfo(compilationUnitComment);
var commentTrivia = SyntaxFactory.SyntaxTrivia(kind, pre + compilationUnitComment.getContent() + post + Environment.NewLine);
leadingTriviaList.Add(commentTrivia);
leadingTriviaList.Add(CreateNonMemberCommentTrivia(compilationUnitComment, Environment.NewLine));
}

if (packageDeclaration is not null)
Expand All @@ -72,9 +68,7 @@ public static CompilationUnitSyntax AddPackageComments(CompilationUnitSyntax syn
{
foreach (var (comment, _) in packageComments)
{
var (kind, pre, post) = GetCommentInfo(comment);
var commentTrivia = SyntaxFactory.SyntaxTrivia(kind, pre + comment.getContent() + post + Environment.NewLine);
leadingTriviaList.Add(commentTrivia);
leadingTriviaList.Add(CreateNonMemberCommentTrivia(comment, Environment.NewLine));
}
}
}
Expand Down Expand Up @@ -128,6 +122,47 @@ public static CompilationUnitSyntax AddPackageComments(CompilationUnitSyntax syn
return syntax;
}

/// <summary>
/// Builds comment trivia for positions that cannot carry XML doc comments, such as file-level
/// and using directive comments. Javadoc is rendered as a block comment instead.
/// </summary>
private static SyntaxTrivia CreateNonMemberCommentTrivia(JavaComments.Comment comment, string suffix = "")
{
var (kind, pre, post) = GetCommentInfo(comment);

if (kind == SyntaxKind.XmlComment)
{
return SyntaxFactory.SyntaxTrivia(SyntaxKind.MultiLineCommentTrivia,
FormatAsBlockComment(comment.getContent()) + suffix);
}

return SyntaxFactory.SyntaxTrivia(kind, pre + comment.getContent() + post + suffix);
}

private static string FormatAsBlockComment(string content)
{
var lines = content.ReplaceLineEndings("\n")
.Split('\n')
.Select(line => line.TrimStart().TrimStart('*').Trim())
.ToList();

TrimTrailingEmptyLines(lines);

while (lines.Count > 0 && lines[0].Length == 0)
{
lines.RemoveAt(0);
}

var builder = new System.Text.StringBuilder("/*");

foreach (var line in lines)
{
builder.Append(Environment.NewLine).Append(line.Length == 0 ? " *" : " * " + line);
}

return builder.Append(Environment.NewLine).Append(" */").ToString();
}

private static (SyntaxKind kind, string? pre, string? post) GetCommentInfo(
JavaComments.Comment comment)
{
Expand Down
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