Fix Version.Parse to show original input in FormatException message when input has trailing dots

[Copilot]

• Understand the issue: Version.Parse with trailing dots shows empty string in error message
• Analyze the code to identify where the fix should be applied
• Design a minimal fix to pass original input for error messages
• Add comprehensive tests for the fix
• Build the changes successfully
• Run tests to verify the fix works
• Verify all tests pass - 69,511 tests passed, 0 failed
• Address code review: refactor to use non-throwing path
• Move throwOnFailure block to [DoesNotReturn] static local function
• Add tests for invalid UTF8 byte sequences
• Deduplicate FormatException throw statement
• Remove unnecessary if condition before ThrowIfNegative

Summary

Fixed Version.Parse to include the original input string in FormatException messages when parsing fails due to trailing dots or empty components.

Changes:

1. Modified TryParseComponent to accept original input parameter
2. Refactored to use non-throwing Number.TryParseBinaryIntegerStyle path for better performance
3. Moved exception throwing logic to a [DoesNotReturn] static local function
4. Deduplicated FormatException throw by extracting string conversion to a local variable
5. Removed unnecessary if condition - ThrowIfNegative already performs the check
6. Added tests for invalid UTF8 byte sequences to ensure robust error handling

Verification:

• All 69,511 System.Runtime tests pass with no failures
• Error messages now show original input (e.g., "The input string '1.' was not in a correct format")
• Properly handles overflow, format errors, and invalid UTF8 sequences

Original prompt

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This section details on the original issue you should resolve

<issue_title>Empty parameter value in FormatException thrown by Version.Parse when input has trailing .</issue_title>
<issue_description>### Description

Version.Parse(".") throws FormatException with the message The input string '' was not in a correct format.

Reproduction Steps

var v = Version.Parse(".");

var v = Version.Parse("1.");

var v = Version.Parse("1.0.");

Expected behavior

The input string '1.0.' was not in a correct format

Actual behavior

The input string '' was not in a correct format

Regression?

No response

Known Workarounds

No response

Configuration

10.0.0-preview.4.25258.110

Other information

No response</issue_description>

Comments on the Issue (you are @copilot in this section)

@jeffhandley Marked as https://github.com/dotnet/runtime/labels/help%20wanted. A fix would need to come with thorough tests, ideally improving the existing test coverage not only related to this specific behavior change, but any other potentially affected behaviors.

Fixes #115612

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[Copilot]

Pull Request Overview

This PR fixes a bug where Version.Parse displayed an empty string in error messages when parsing failed due to trailing dots (e.g., "1.0."). The fix ensures the original input string is included in FormatException messages for better diagnostics.

Key Changes:

• Modified TryParseComponent to accept and use the original input string for error messages
• Refactored error handling to use non-throwing TryParseBinaryIntegerStyle for better performance
• Added comprehensive test coverage for trailing dot scenarios and invalid UTF8 sequences

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/libraries/System.Private.CoreLib/src/System/Version.cs	Updated TryParseComponent to accept original input parameter and refactored exception throwing to a [DoesNotReturn] static local function
src/libraries/System.Runtime/tests/System.Runtime.Tests/System/VersionTests.cs	Added tests for trailing dots with string/span/UTF8 inputs and invalid UTF8 byte sequences

[stephentoub]

@EgorBot -amd -intel -arm

using System;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

BenchmarkSwitcher.FromAssembly(typeof(Benchmarks).Assembly).Run(args);

public class Benchmarks
{
    [Benchmark]
    [Arguments("1.2")]
    [Arguments("123.123.123.123")]
    public Version Parse(string s) => Version.Parse(s);
}

[stephentoub]

@EgorBo, looks like your bot might need to bump some version numbers?

[stephentoub]

@copilot, this if condition should not be necessary, as it's going to be checked by ThrowIfNegative

Suggested change

	if (parsedComponent < 0)
	{
	ArgumentOutOfRangeException.ThrowIfNegative(parsedComponent, componentName);
	}
	ArgumentOutOfRangeException.ThrowIfNegative(parsedComponent, componentName);

[Copilot]

Done in commit 2fcaa84. Removed the unnecessary if (parsedComponent < 0) condition since ThrowIfNegative already performs this check.

[EgorBo]

@EgorBo, looks like your bot might need to bump some version numbers?

Yep, seems to be fixed now