What is the solution id that appears in the manifest.xml of a .wsp file

Question

What is the solution id for?

For example

<Solution xmlns="http://schemas.microsoft.com/sharepoint/" SolutionId="12345678-c983-4553-1234-74c609831d33" SharePointProductVersion="14.0">

Answer 1

Most things in SharePoint are tracked/identified by GUIDs. Solution packages are no different. It is probably of little consequence to most developers.

There are situations where it can come into play. One example is when you attempt to update a solution package with the same name but different Id. SharePoint will prevent you from doing this since it thinks (reasonably) that the packages are different and therefore should not be updatable.

I've run into the above situation where multiple developers (or even one developer with different development environments) builds a solution using a tool such as WSPBuilder and the source that they shared in source control did not include the file with the solution id in it. The result is that different environments potentially build what is effectively the same package because the source is shared, but assign different solution ids.

That seemed like a long response for a simple question. :P