PS0083: Invalid Date in an Attribute of a Task

Cause

A configuration file, such as postsharp.config or a .psproj file, can configure the tasks of the PostSharp compiler with a Tasks section: each element names a task, and its attributes set the properties of the task. PostSharp first evaluates the expressions of the attribute value, such as {$PropertyName}, then converts the result to the type of the property.

When the property is a date, PostSharp reads the value in the XML Schema format (xs:dateTime), for example 2026-10-15, 2026-10-15T09:30:00 or 2026-10-15T09:30:00+02:00. PostSharp reports PS0083 when <Value>, the evaluated value of the attribute <Attribute> of the task <Task>, is not in this format, for example 15/10/2026. The error stops the build.

No task of PostSharp or of its packages has a date property, so only the task of a third-party plug-in can report this message, and no example can show it.

Resolution

• Write the date in the XML Schema format: year, month and day separated by hyphens, then optionally T, the time, and the time zone, as in 2026-10-15T09:30:00Z.
• When the attribute uses a property, such as {$BuildDate}, check the value that the property receives, for example in the PostSharpProperties MSBuild property: the evaluated value is what PostSharp reads.
• When you do not need to set the attribute, remove it.

See Also

Other Resources

Configuring Projects Using postsharp.config
Configuration File Schema Reference
Well-Known PostSharp Properties