NRE in `GetFileList`

[rainersigwald]

Got a report of this error (coming from the NuGet executable inside a static-graph restore):

MSBuild version = "17.14.0-preview-25105-02+915bcd94d"

Object reference not set to an instance of an object.
   at System.Object.GetType()
   at Microsoft.Build.Internal.EngineFileUtilities.GetFileList(String directoryEscaped, String filespecEscaped, Boolean returnEscaped, Boolean forceEvaluateWildCards, IEnumerable`1 excludeSpecsEscaped, FileMatcher fileMatcher, Object loggingMechanism, IElementLocation includeLocation, IElementLocation excludeLocation, IElementLocation importLocation, BuildEventContext buildEventContext, String buildEventFileInfoFullPath, Boolean disableExcludeDriveEnumerationWarning)
   at Microsoft.Build.Evaluation.Expander`2.ItemExpander.IntrinsicItemFunctions`1.<GetItemPairEnumerable>d__3.MoveNext()
   at Microsoft.Build.Evaluation.Expander`2.ItemExpander.IntrinsicItemFunctions`1.<GetPathsOfAllDirectoriesAbove>d__8.MoveNext()
   at Microsoft.Build.Evaluation.Expander`2.ItemExpander.<Transform>d__0`1.MoveNext()
   at Microsoft.Build.Evaluation.Expander`2.ItemExpander.<Transform>d__0`1.MoveNext()
   at Microsoft.Build.Evaluation.Expander`2.ItemExpander.ExpandExpressionCapture[S](Expander`2 expander, ItemExpressionCapture expressionCapture, IItemProvider`1 evaluatedItems, IElementLocation elementLocation, ExpanderOptions options, Boolean includeNullEntries, Boolean& isTransformExpression, List`1& itemsFromCapture)
   at Microsoft.Build.Evaluation.Expander`2.ItemExpander.ExpandExpressionCaptureIntoItems[S,T](ItemExpressionCapture expressionCapture, Expander`2 expander, IItemProvider`1 items, IItemFactory`2 itemFactory, ExpanderOptions options, Boolean includeNullEntries, Boolean& isTransformExpression, IElementLocation elementLocation)
   at Microsoft.Build.Evaluation.LazyItemEvaluator`4.IncludeOperation.SelectItems(Builder listBuilder, ImmutableHashSet`1 globsToIgnore)
   at Microsoft.Build.Evaluation.LazyItemEvaluator`4.LazyItemOperation.ApplyImpl(Builder listBuilder, ImmutableHashSet`1 globsToIgnore)
   at Microsoft.Build.Evaluation.LazyItemEvaluator`4.LazyItemOperation.Apply(Builder listBuilder, ImmutableHashSet`1 globsToIgnore)
   at Microsoft.Build.Evaluation.LazyItemEvaluator`4.LazyItemList.ComputeItems(LazyItemList lazyItemList, ImmutableHashSet`1 globsToIgnore)
   at Microsoft.Build.Evaluation.LazyItemEvaluator`4.LazyItemList.GetItemData(ImmutableHashSet`1 globsToIgnore)
   at System.Linq.Enumerable.<SelectManyIterator>d__17`2.MoveNext()
   at System.Linq.Buffer`1..ctor(IEnumerable`1 source)
   at System.Linq.OrderedEnumerable`1.<GetEnumerator>d__1.MoveNext()
   at Microsoft.Build.Evaluation.Evaluator`4.Evaluate()
   at Microsoft.Build.Evaluation.Evaluator`4.Evaluate(IEvaluatorData`4 data, Project project, ProjectRootElement root, ProjectLoadSettings loadSettings, Int32 maxNodeCount, PropertyDictionary`1 environmentProperties, ILoggingService loggingService, IItemFactory`2 itemFactory, IToolsetProvider toolsetProvider, IDirectoryCacheFactory directoryCacheFactory, ProjectRootElementCacheBase projectRootElementCache, BuildEventContext buildEventContext, ISdkResolverService sdkResolverService, Int32 submissionId, EvaluationContext evaluationContext, Boolean interactive)
   at Microsoft.Build.Execution.ProjectInstance.Initialize(ProjectRootElement xml, IDictionary`2 globalProperties, String explicitToolsVersion, String explicitSubToolsetVersion, Int32 visualStudioVersionFromSolution, BuildParameters buildParameters, ILoggingService loggingService, BuildEventContext buildEventContext, ISdkResolverService sdkResolverService, Int32 submissionId, Nullable`1 projectLoadSettings, EvaluationContext evaluationContext, IDirectoryCacheFactory directoryCacheFactory)
   at Microsoft.Build.Execution.ProjectInstance..ctor(String projectFile, IDictionary`2 globalProperties, String toolsVersion, String subToolsetVersion, ProjectCollection projectCollection, Nullable`1 projectLoadSettings, EvaluationContext evaluationContext, IDirectoryCacheFactory directoryCacheFactory, Boolean interactive)
   at Microsoft.Build.Execution.ProjectInstance.FromFile(String file, ProjectOptions options)
   at Microsoft.Build.Graph.GraphBuilder.ParseProject(ConfigurationMetadata configurationMetadata)
   at System.Lazy`1.CreateValue()
   at System.Lazy`1.LazyInitValue()
   at Microsoft.Build.Graph.ParallelWorkSet`2.ExecuteWorkItem()

let's at least turn nullable analysis on for this method:

msbuild/src/Build/Utilities/EngineFileUtilities.cs

Lines 173 to 389 in 0f46612

	private static string[] GetFileList(
	string directoryEscaped,
	string filespecEscaped,
	bool returnEscaped,
	bool forceEvaluateWildCards,
	IEnumerable<string> excludeSpecsEscaped,
	FileMatcher fileMatcher,
	object loggingMechanism = null,
	IElementLocation includeLocation = null,
	IElementLocation excludeLocation = null,
	IElementLocation importLocation = null,
	BuildEventContext buildEventContext = null,
	string buildEventFileInfoFullPath = null,
	bool disableExcludeDriveEnumerationWarning = false)
	{
	ErrorUtilities.VerifyThrowInternalLength(filespecEscaped, nameof(filespecEscaped));
	string[] fileList = [];
	// Used to properly detect and log drive enumerating wildcards when applicable.
	string excludeFileSpec = string.Empty;
	var filespecHasNoWildCards = !FilespecHasWildcards(filespecEscaped);
	var filespecMatchesLazyWildcard = FilespecMatchesLazyWildcard(filespecEscaped, forceEvaluateWildCards);
	var excludeSpecsAreEmpty = excludeSpecsEscaped?.Any() != true;
	// Return original value if:
	// FileSpec matches lazyloading regex or
	// file has no wildcard and excludeSpecs are empty
	if (filespecMatchesLazyWildcard || (filespecHasNoWildCards && excludeSpecsAreEmpty))
	{
	// Just return the original string.
	fileList = [returnEscaped ? filespecEscaped : EscapingUtilities.UnescapeAll(filespecEscaped)];
	}
	else
	{
	if (Traits.Instance.LogExpandedWildcards)
	{
	ErrorUtilities.DebugTraceMessage("Expanding wildcard for file spec {0}", filespecEscaped);
	}
	// Unescape before handing it to the filesystem.
	var directoryUnescaped = EscapingUtilities.UnescapeAll(directoryEscaped);
	var filespecUnescaped = EscapingUtilities.UnescapeAll(filespecEscaped);
	var excludeSpecsUnescaped = excludeSpecsEscaped?.Where(IsValidExclude).Select(i => EscapingUtilities.UnescapeAll(i)).ToList();
	// Extract file spec information
	FileMatcher.Default.GetFileSpecInfo(filespecUnescaped, out string directoryPart, out string wildcardPart, out string filenamePart, out bool needsRecursion, out bool isLegalFileSpec);
	// Check if the file spec contains a drive-enumerating wildcard
	bool logDriveEnumeratingWildcard = FileMatcher.IsDriveEnumeratingWildcardPattern(directoryPart, wildcardPart);
	// Process exclude specs (if provided) and check if any of them contain a drive-enumerating wildcard
	if (excludeSpecsUnescaped != null)
	{
	foreach (string excludeSpec in excludeSpecsUnescaped)
	{
	FileMatcher.Default.GetFileSpecInfo(excludeSpec, out directoryPart, out wildcardPart, out filenamePart, out needsRecursion, out isLegalFileSpec);
	bool logDriveEnumeratingWildcardFromExludeSpec = FileMatcher.IsDriveEnumeratingWildcardPattern(directoryPart, wildcardPart);
	if (logDriveEnumeratingWildcardFromExludeSpec)
	{
	excludeFileSpec = excludeSpec;
	}
	logDriveEnumeratingWildcard |= logDriveEnumeratingWildcardFromExludeSpec;
	}
	}
	// Determines whether Exclude filespec or passed in file spec should be
	// used in drive enumeration warning or exception.
	bool excludeFileSpecIsEmpty = string.IsNullOrWhiteSpace(excludeFileSpec);
	string fileSpec = excludeFileSpecIsEmpty ? filespecUnescaped : excludeFileSpec;
	if (logDriveEnumeratingWildcard)
	{
	switch (loggingMechanism)
	{
	// Logging mechanism received from ItemGroupIntrinsicTask.
	case TargetLoggingContext targetLoggingContext:
	LogDriveEnumerationWarningWithTargetLoggingContext(
	targetLoggingContext,
	includeLocation,
	excludeLocation,
	excludeFileSpecIsEmpty,
	disableExcludeDriveEnumerationWarning,
	fileSpec);
	break;
	// Logging mechanism received from Evaluator.
	case ILoggingService loggingService:
	LogDriveEnumerationWarningWithLoggingService(
	loggingService,
	includeLocation,
	buildEventContext,
	buildEventFileInfoFullPath,
	filespecUnescaped);
	break;
	// Logging mechanism received from Evaluator and LazyItemEvaluator.IncludeOperation.
	case EvaluationLoggingContext evaluationLoggingContext:
	LogDriveEnumerationWarningWithEvaluationLoggingContext(
	evaluationLoggingContext,
	importLocation,
	includeLocation,
	excludeLocation,
	excludeFileSpecIsEmpty,
	filespecUnescaped,
	fileSpec);
	break;
	default:
	throw new InternalErrorException(ResourceUtilities.FormatResourceStringIgnoreCodeAndKeyword(
	"UnknownLoggingType",
	loggingMechanism.GetType(),
	nameof(GetFileList)));
	}
	}
	if (logDriveEnumeratingWildcard && Traits.Instance.ThrowOnDriveEnumeratingWildcard)
	{
	switch (loggingMechanism)
	{
	// Logging mechanism received from ItemGroupIntrinsicTask.
	case TargetLoggingContext targetLoggingContext:
	ThrowDriveEnumerationExceptionWithTargetLoggingContext(
	includeLocation,
	excludeLocation,
	excludeFileSpecIsEmpty,
	filespecUnescaped,
	fileSpec);
	break;
	// Logging mechanism received from Evaluator.
	case ILoggingService loggingService:
	ThrowDriveEnumerationExceptionWithLoggingService(includeLocation, filespecUnescaped);
	break;
	// Logging mechanism received from Evaluator and LazyItemEvaluator.IncludeOperation.
	case EvaluationLoggingContext evaluationLoggingContext:
	ThrowDriveEnumerationExceptionWithEvaluationLoggingContext(
	importLocation,
	includeLocation,
	excludeLocation,
	filespecUnescaped,
	fileSpec,
	excludeFileSpecIsEmpty);
	break;
	default:
	throw new InternalErrorException(ResourceUtilities.FormatResourceStringIgnoreCodeAndKeyword(
	"UnknownLoggingType",
	loggingMechanism.GetType(),
	nameof(GetFileList)));
	}
	}
	else
	{
	// Get the list of actual files which match the filespec. Put
	// the list into a string array. If the filespec started out
	// as a relative path, we will get back a bunch of relative paths.
	// If the filespec started out as an absolute path, we will get
	// back a bunch of absolute paths
	(fileList, _, _, string globFailure) = fileMatcher.GetFiles(directoryUnescaped, filespecUnescaped, excludeSpecsUnescaped);
	// log globing failure with the present logging mechanism
	if (globFailure != null)
	{
	switch (loggingMechanism)
	{
	case TargetLoggingContext targetLoggingContext:
	targetLoggingContext.LogCommentFromText(MessageImportance.Low, globFailure);
	break;
	case ILoggingService loggingService:
	loggingService.LogCommentFromText(buildEventContext, MessageImportance.Low, globFailure);
	break;
	case EvaluationLoggingContext evaluationLoggingContext:
	evaluationLoggingContext.LogCommentFromText(MessageImportance.Low, globFailure);
	break;
	default:
	throw new InternalErrorException(ResourceUtilities.FormatResourceStringIgnoreCodeAndKeyword(
	"UnknownLoggingType",
	loggingMechanism.GetType(),
	nameof(GetFileList)));
	}
	}
	ErrorUtilities.VerifyThrow(fileList != null, "We must have a list of files here, even if it's empty.");
	// Before actually returning the file list, we sort them alphabetically. This
	// provides a certain amount of extra determinism and reproducability. That is,
	// we're sure that the build will behave in exactly the same way every time,
	// and on every machine.
	Array.Sort(fileList, StringComparer.OrdinalIgnoreCase);
	if (returnEscaped)
	{
	// We must now go back and make sure all special characters are escaped because we always
	// store data in the engine in escaped form so it doesn't interfere with our parsing.
	// Note that this means that characters that were not escaped in the original filespec
	// may now be escaped, but that's not easy to avoid.
	for (int i = 0; i < fileList.Length; i++)
	{
	fileList[i] = EscapingUtilities.Escape(fileList[i]);
	}
	}
	}
	}
	return fileList;
	}