Fixes a code gen bug, fixes false positives with NoVoidTypeOfExpressionsInGeneratedCode test

[mamift]

• Fixes a code gen bug: when a schema imports another schema that contains a global attribute whose schema type was anonymous and had enums, LinqToXsd will now properly generate the C# enum definition.
• added powershell for regenerating code in test libraries under (GeneratedSchemaLibraries)
• fixes bug with ResolveFileAndFolderPathsToJustFiles, added tests for ResolvePossibleFileAndFolderPathsToProcessableSchemas
• Fixes false positives with NoVoidTypeOfExpressionsInGeneratedCode test
• Added a new type Graph that can more easily model the connections between a bunch of XSDs that include or import each other. Usable only in unit tests for now.

v3.4.20

[Copilot]

🟡 Changes recommended

Several newly introduced graph/schema utilities have concrete correctness issues (null-safety, path normalisation, stubbed/empty implementations) that can cause runtime exceptions or silently incorrect results.

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Pull request overview

This PR updates LinqToXsdCore’s schema-processing and test tooling to better handle multi-XSD import/include graphs (including cycles), fixes a codegen edge case around anonymous-enum attribute types, and reduces false positives in the NoVoidTypeOfExpressionsInGeneratedCode test by selecting more appropriate entry-point XSDs.

Changes:

• Fix anonymous-type detection for referenced global attributes so enum definitions are generated correctly.
• Add SCC-based entry-point selection for XSD sets (plus an import/include report utility) and new tests around path resolution / GitHub Issue 71.
• Introduce an XSD-backed Graph model (generated + partial) and supporting test/script updates for regenerating schema libraries.

File summaries

File	Description
XObjectsTests/XObjectsTests.csproj	Adds System.Text.Json for new tests reading .slnf JSON.
XObjectsTests/Utilities.cs	Adds schema-set preloading/compilation path and preserves exception stack traces via ExceptionDispatchInfo.
XObjectsTests/MockXmlUrlResolver.cs	Improves resolver matching for absolute vs filename-only URIs; tweaks ResolveUri matching logic.
XObjectsTests/GraphTests.cs	Adds coverage for building/serialising the new Graph and basic entry-point detection.
XObjectsTests/FileSystemUtilitiesTests.cs	Adds tests for SCC-based schema entry-point selection and import/include reporting.
XObjectsTests/Extensions/MockFileSystemExtensions.cs	Updates test helper to use SCC-based entry-point detection; adds BuildGraph helper.
XObjectsTests/Extensions/DirectoryExtensions.cs	Adds AscendByLevel helper used by filesystem-based tests.
XObjectsTests/CodeGenerationTests.cs	Switches void-type checks to graph-derived entry points; adds (currently empty) regression test placeholder.
XObjectsCore/XAttributeValueEqualityComparer.cs	Adds Default singleton for consistent comparer usage.
XObjectsCore/FileSystemUtilities.cs	Renames/reshapes filtering parameters; replaces previous heuristic with SCC-based entry-point detection; adds report generator.
XObjectsCore/Extensions/XDocumentExtensions.cs	Adds include/import helpers and SCC-based entry-point selection (Tarjan) for file-path→XDocument inputs.
XObjectsCore/Extensions/StringExtensionMethods.cs	Adds ignore-case equality helpers used by new graph logic.
XObjectsCore/Extensions/GeneralExtensionMethods.cs	Adds ValueForPossibleKeys for dictionary lookups with fallback keys.
XObjectsCode/XObjectsCodeGen.csproj	Adds System.IO.Abstractions dependency used by graph building from an IFileSystem.
XObjectsCode/XImportGraph.xsd.config	Adds config for generating the Graph type model.
XObjectsCode/XImportGraph.xsd-g.cs	Adds generated types for Graph/Schema model used by tests/code.
XObjectsCode/XImportGraph.xsd	Adds the schema defining the Graph/Schema XML model.
XObjectsCode/Graph.cs	Adds partial implementation for building/traversing XSD dependency graphs and choosing SCC-based entry points.
XObjectsCode/Extensions/XmlSchemaExtensions.cs	Fixes anonymous-type detection for attribute references with anonymous resolved types.
XObjectsCode/Extensions/GraphExtensions.cs	Adds (currently stubbed) traversal extension.
Version.props	Bumps version to 3.4.20.
Regenerate-TestingSuite.ps1	Adds script to regenerate generated schema libraries from the solution filter list.
LinqToXsd/Properties/launchSettings.json	Adds launch profiles for new schemas/tests.
LinqToXsd.Schemas/XsdFeatureTests/ImportsXmlNamespace/ImportsXmlAttributes.xsd.config	Enables AlwaysPrefixGlobal to reduce naming collisions in generated code.
LinqToXsd.Schemas/XsdFeatureTests/ImportsXmlNamespace/ImportsXmlAttributes.xsd-g.cs	Updates generated output for import/xml namespace attribute enum scenario.
LinqToXsd.Schemas/Tests/GithubIssue71/xmldsig-core-schema.xsd.config	Adds config for Issue 71 test schema set.
LinqToXsd.Schemas/Tests/GithubIssue71/xmldsig-core-schema.xsd	Adds Issue 71 dependency XSD fixture.
LinqToXsd.Schemas/Tests/GithubIssue71/V2G_CI_MsgHeader.xsd	Adds Issue 71 cyclic-import graph fixture.
LinqToXsd.Schemas/Tests/GithubIssue71/V2G_CI_MsgDef.xsd	Adds Issue 71 cyclic-import graph fixture.
LinqToXsd.Schemas/Tests/GithubIssue71/V2G_CI_MsgDataTypes.xsd.config	Adds config for Issue 71 cyclic-import graph fixture.
LinqToXsd.Schemas/Tests/GithubIssue71/V2G_CI_MsgDataTypes.xsd	Adds Issue 71 cyclic-import graph fixture.
LinqToXsd.Schemas/Tests/GithubIssue71/V2G_CI_MsgBody.xsd	Adds Issue 71 cyclic-import graph fixture.
LinqToXsd.Schemas/Tests/GithubIssue71/V2G_CI_AppProtocol.xsd.config	Adds config for standalone schema fixture.
LinqToXsd.Schemas/Tests/GithubIssue71/V2G_CI_AppProtocol.xsd	Adds standalone schema fixture for Issue 71.
LinqToXsd.Schemas/LinqToXsd.Schemas.csproj	Adjusts embedded resource handling for ImportsXmlAttributes XSD.
GeneratedSchemaLibraries/1707_ISYBAU_XML_Schema/1707-metadaten.xsd.config	Normalises config (adds CodeGeneration section; updates XMLSchema CLR namespace mapping).
fuse.json	Adds Fuse workspace config file.
Directory.Build.props	Adds NETSDK1138 to NoWarn.
CLAUDE.md	Adds Fuse workflow guidance block.
AGENTS.md	Adds Fuse workflow guidance block.
.mcp.json	Adds MCP server entries for code-review-graph and fuse.
.gitignore	Ignores .fuse/ directory.
.github/copilot-instructions.md	Adds Fuse workflow guidance for Copilot.

Review details

Suppressed comments (3)

XObjectsCore/Extensions/XDocumentExtensions.cs:37

• Same as GetXsdIncludeElements: matching only by LocalName can include elements from other namespaces. Prefer using ImportXName to ensure you only capture xs:import elements.
  XObjectsCode/Graph.cs:236
• FindEntryPointSchemas accesses SchemaField directly; on Graph instances created via Parse/Load, SchemaField can still be null until the Schema property is accessed, leading to NullReferenceException. Use the Schema property instead of the backing field.

    public List<Schema> FindEntryPointSchemas()
    {
        List<string> entryPointNames = FindEntryPointSchemaNames();

        return this.SchemaField
            .Where(sc => entryPointNames.Any(e => e.EqualsIgnoreCase(sc.Name)))
            .ToList();
    }

XObjectsCode/Graph.cs:447

• GetDependencies assumes include/import Schema.Name matches the root schema Name exactly and uses Single(), but BuildFromFolder stores schemaLocation values (often relative paths). This can cause InvalidOperationException (no match) even when the dependency exists. Normalise to Path.GetFileName and skip/raise a clearer error when the dependency isn’t present in the graph.

    public IEnumerable<Schema> GetDependencies()
    {
        // since this Schema represents a <Schema> XML element under the <Graph> XML element,
        // we can conveniently navigate to the parent by casting to the right type!
        Graph graph = (Graph)this.Untyped.Parent;
        
        if (Includes?.Schema != null && Includes.Schema.Any())
        {
            foreach (Schema include in Includes.Schema)
            {
                var schemaByNameFromGraphRoot = graph.Schema.Single(s => s.Name.EqualsIgnoreCase(include.Name));
                yield return schemaByNameFromGraphRoot;
            }
        }

        if (Imports?.Schema != null && Imports.Schema.Any())
        {
            foreach (Schema import in Imports.Schema)
            {
                var schemaByNameFromGraphRoot = graph.Schema.Single(s => s.Name.EqualsIgnoreCase(import.Name));
                yield return schemaByNameFromGraphRoot;
            }
        }
    }

• Files reviewed: 42/43 changed files
• Comments generated: 10
• Review effort level: Lite

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