Do NOT Change "Copy Local” project references to false, unless understand subsequences.

To optimize performance of visual studio build I've found multiple recommendations to change CopyLocal property for dependent dlls to false,

  1. e.g. From http://stackoverflow.com/questions/690033/best-practices-for-large-solutions-in-visual-studio-2008 
  • CopyLocal? For sure turn this off

  • Always set the Copy Local property to false and enforce this via a custom msbuild step
  • My advice is to always set ‘Copy Local’ to false

Some time ago we've tried to change the setting to false, and found that it causes problem for deployment of top-level projects.

Recently I've followed the suggestion and changed the settings for middle-level projects. It didn't cause immediate issues, but I was warned by Readify Consultant Colin Savage about possible errors during deployments

I haven't undone the changes immediately and we found a few issues during testing.

There are many scenarios, when you need to have Copy Local' left to True.

The concerns are highlighted in some StackOverflow answers, but they have small number of votes.The concerns are highlighted in some StackOverflow answers, but they have small number of votes.

Top-level projects:  set copy local = true.


First of all, it doesn't work correctly for top-level projects, i.e. executables or web sites.
  • for all the references in the one at the top set copy local = true.
 
 
If you set ‘ Copy Local = false’, VS will, unless you tell it otherwise, place each assembly alone in its own .\bin\Debugdirectory. Because of this, you will need to configure VS to place assemblies together in the same directory. To do so, for each VS project, go to VS > Project Properties > Build tab > Output path, and set the Ouput path to ..\bin\Debugfor debug configuration, and ..\bin\Release for release configuration.

Second-level  dependencies:  set copy local = true.

Another example when copylocal =false fails on run-time, is when top level assembly doesn't directly referenced one of indirect dependencies.
E..g. Top-level assembly A has reference to assembly B with copylocal =true, but assembly B has reference to assembly C with copylocal =false. Most likely assembly C will be missing on runtime and will cause errors 

Copy local is important for deployment scenarios and tools. As a general rule you should use CopyLocal=True
 
and http://stackoverflow.com/questions/602765/when-should-copy-local-be-set-to-true-and-when-should-it-not?lq=1

Unfortunately there are some quirks and CopyLocal won't necessary work as expected for assembly references in secondary assemblies structured as shown below.

  • MainApp.exe
    • MyLibrary.dll
      • ThirdPartyLibrary.dll (if in the GAC CopyLocal won't copy to MainApp bin folder)

This makes xcopy deployments difficult . 

Reflection called DLLs  dependencies:  set copy local = true.
E.g user can see error "ISystem.Reflection.ReflectionTypeLoadException: Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information."

The fix for the issue is recommended in http://stackoverflow.com/a/6200173/52277


"I solved this issue by setting the Copy Local attribute of my project's references to true."


In general, the problems with investigation of deployment issues may overweight the benefits of reduced build time.
 
Setting the Copy Local to false without considering deployment issues is not a good idea. 


 
posted @ Sunday, December 9, 2012 1:15 PM
Print

Comments on this entry:

# re: Do NOT Change "Copy Local” project references to false, unless understand subsequences.

Left by George S at 1/5/2013 8:09 AM
Gravatar
You guys are complicating the entire issue.

CopyLocal should be set to true for websites and application exes. CopyLocal should be set to false for all you DLL projects if you are dumping them into a common bin. If you don't, then you will end up overwriting newly compiled DLL's with older DLL's from your Hint Path references.

# re: Do NOT Change "Copy Local” project references to false, unless understand subsequences.

Left by Sven Neubert at 2/5/2013 4:01 AM
Gravatar
@George

I think the issue mentioned in 'Second-level dependencies' will still exist if the host is a webproject.

# re: Do NOT Change "Copy Local” project references to false, unless understand subsequences.

Left by foo at 6/26/2013 7:14 PM
Gravatar
This blog entry is completely unreadable. It's not 1989 anymore...

# Regarding Kendo UI in Azure

Left by Pradeep Kumar T at 10/7/2013 4:40 PM
Gravatar
I have a project with Kendo UI, In Azure no kendo controls are working, can you guide me regarding DLL that has to be added in this case. And we are trying to host in the Azure Cloud Server.

It works fine in Non-Azure.


For Kendo Grid: Error is ::Index must be within the bounds of the List.Parameter name: index

For Kendo AutoComplete ::Entry point was not found.

Your comment:



(not displayed)

 
 
 
 
 

Live Comment Preview:

 
«July»
SunMonTueWedThuFriSat
293012345
6789101112
13141516171819
20212223242526
272829303112
3456789