When should you prefer ReBuild instead of Build?

Question

Just to make it more clear for me, I would like to ask you guys the correct condition(s) to have your

project or solution Rebuild instead of build in Visual Studio?

If I rephrase it: Why the MS needed to create "Re-build ALL" option in Visual Studio? What was their main motive to do that?

Thanks!

Answer 1

DRY : Rebuild = Clean + Build for each project in turn.

Build does not delete the previous builds outputs. Rebuild does delete them and build again (one project at a time if you are in a solution : delete proj1\bin\Debug, build proj1, delete proj2\bin\Debug ...).

The main case when I do a rebuild (or a clean build) is when I need to update my solution third dependencies. Let's see the following folder tree :

    SOLUTION
      |__Dependencies
      |__PROJ_1
         |__bin
         |__obj
         |__(code)
      |__PROJ_2
         |__bin
         |__obj
         |__(code)

If I change my dlls in Dependencies and don't do a rebuild, VS (and MsBuild) would still use the previous dll version that is in PROJ_N\bin\Debug (or in bin\Release), because of the Dependency lookup order (see http://www.beefycode.com/post/Resolving-Binary-References-in-MSBuild.aspx) :

1. Files from current project - indicated by {CandidateAssemblyFiles}
2. $(ReferencePath) - the reference path property, which comes from the .USER file.
3. The hintpath from the referenced item itself, indicated by {HintPathFromItem}.
   ...

The dll in bin folder goes in the the first lookup case, the dll in Dependencies folder comes in the second case...

In such a case I would do a clean (Debug), clean (Release) and then a build to eradicate all previous version in the bin folder. I'm maybe a bit overkill and a rebuild may be enough but I'm not sure because the dlls are in the Debug and in the Release folders...

Answer 2

Sometimes things go wrong and the build just doesn't work.

This happens e.g. when I do not correctly update dependent libraries which then aren't correctly copied to the bin paths of the build. There are other examples, non spring to mind.

That's when I use rebuild.