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WriteLinesToFile improvements #12707

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Merged
merged 2 commits into from
Nov 4, 2025
Merged

WriteLinesToFile improvements #12707

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jeffkl Oct 29, 2025
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jeffkl Oct 29, 2025
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137 changes: 68 additions & 69 deletions src/Tasks/FileIO/WriteLinesToFile.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -60,101 +60,100 @@ public class WriteLinesToFile : TaskExtension, IIncrementalTask
[Obsolete]
public bool CanBeIncremental => WriteOnlyWhenDifferent;

/// <summary>
/// Execute the task.
/// </summary>
/// <returns></returns>
/// <inheritdoc cref="ITask.Execute" />
public override bool Execute()
{
bool success = true;

if (File != null)
if (File == null)
{
return success;
}

string filePath = FileUtilities.NormalizePath(File.ItemSpec);

string contentsAsString = string.Empty;

if (Lines != null && Lines.Length > 0)
{
// do not return if Lines is null, because we may
// want to delete the file in that case
StringBuilder buffer = new StringBuilder();
if (Lines != null)
StringBuilder buffer = new StringBuilder(capacity: Lines.Length * 64);

foreach (ITaskItem line in Lines)
{
foreach (ITaskItem line in Lines)
{
buffer.AppendLine(line.ItemSpec);
}
buffer.AppendLine(line.ItemSpec);
}

Encoding encoding = s_defaultEncoding;
if (Encoding != null)
contentsAsString = buffer.ToString();
}

Encoding encoding = s_defaultEncoding;
if (Encoding != null)
{
try
{
try
{
encoding = System.Text.Encoding.GetEncoding(Encoding);
}
catch (ArgumentException)
{
Log.LogErrorWithCodeFromResources("General.InvalidValue", "Encoding", "WriteLinesToFile");
return false;
}
encoding = System.Text.Encoding.GetEncoding(Encoding);
}
catch (ArgumentException)
{
Log.LogErrorWithCodeFromResources("General.InvalidValue", "Encoding", "WriteLinesToFile");
return false;
}
}

try
try
{
Directory.CreateDirectory(Path.GetDirectoryName(filePath));

if (Overwrite)
{
var directoryPath = Path.GetDirectoryName(FileUtilities.NormalizePath(File.ItemSpec));
if (Overwrite)
// When WriteOnlyWhenDifferent is set, read the file and if they're the same return.
if (WriteOnlyWhenDifferent)
{
Directory.CreateDirectory(directoryPath);
string contentsAsString = buffer.ToString();

// When WriteOnlyWhenDifferent is set, read the file and if they're the same return.
if (WriteOnlyWhenDifferent)
MSBuildEventSource.Log.WriteLinesToFileUpToDateStart();
try
{
MSBuildEventSource.Log.WriteLinesToFileUpToDateStart();
try
if (FileUtilities.FileExistsNoThrow(filePath))
{
if (FileUtilities.FileExistsNoThrow(File.ItemSpec))
string existingContents = FileSystems.Default.ReadFileAllText(filePath);

if (existingContents.Equals(contentsAsString))
{
string existingContents = FileSystems.Default.ReadFileAllText(File.ItemSpec);
if (existingContents.Length == buffer.Length)
{
if (existingContents.Equals(contentsAsString))
{
Log.LogMessageFromResources(MessageImportance.Low, "WriteLinesToFile.SkippingUnchangedFile", File.ItemSpec);
MSBuildEventSource.Log.WriteLinesToFileUpToDateStop(File.ItemSpec, true);
return true;
}
else if (FailIfNotIncremental)
{
Log.LogErrorWithCodeFromResources("WriteLinesToFile.ErrorReadingFile", File.ItemSpec);
return false;
}
}
Log.LogMessageFromResources(MessageImportance.Low, "WriteLinesToFile.SkippingUnchangedFile", filePath);
MSBuildEventSource.Log.WriteLinesToFileUpToDateStop(filePath, true);
return true;
}
else if (FailIfNotIncremental)
{
Log.LogErrorWithCodeFromResources("WriteLinesToFile.ErrorReadingFile", filePath);
return false;
}
}
catch (IOException)
{
Log.LogMessageFromResources(MessageImportance.Low, "WriteLinesToFile.ErrorReadingFile", File.ItemSpec);
}
MSBuildEventSource.Log.WriteLinesToFileUpToDateStop(File.ItemSpec, false);
}

System.IO.File.WriteAllText(File.ItemSpec, contentsAsString, encoding);
}
else
{
if (WriteOnlyWhenDifferent)
catch (IOException)
{
Log.LogMessageFromResources(MessageImportance.Normal, "WriteLinesToFile.UnusedWriteOnlyWhenDifferent", File.ItemSpec);
Log.LogMessageFromResources(MessageImportance.Low, "WriteLinesToFile.ErrorReadingFile", filePath);
}

Directory.CreateDirectory(directoryPath);
System.IO.File.AppendAllText(File.ItemSpec, buffer.ToString(), encoding);
MSBuildEventSource.Log.WriteLinesToFileUpToDateStop(filePath, false);
}

System.IO.File.WriteAllText(filePath, contentsAsString, encoding);
}
catch (Exception e) when (ExceptionHandling.IsIoRelatedException(e))
else
{
string lockedFileMessage = LockCheck.GetLockedFileMessage(File.ItemSpec);
Log.LogErrorWithCodeFromResources("WriteLinesToFile.ErrorOrWarning", File.ItemSpec, e.Message, lockedFileMessage);
success = false;
if (WriteOnlyWhenDifferent)
{
Log.LogMessageFromResources(MessageImportance.Normal, "WriteLinesToFile.UnusedWriteOnlyWhenDifferent", filePath);
}

System.IO.File.AppendAllText(filePath, contentsAsString, encoding);
}
}
catch (Exception e) when (ExceptionHandling.IsIoRelatedException(e))
{
string lockedFileMessage = LockCheck.GetLockedFileMessage(filePath);
Log.LogErrorWithCodeFromResources("WriteLinesToFile.ErrorOrWarning", filePath, e.Message, lockedFileMessage);
success = false;
}

return success;
}
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