The Connection Group Virtual Environment
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How package priority is determined
The virtual environment and its current state are associated with the connection group, not with the individual packages. If an App-V package is removed from the connection group, the state that existed as part of the connection group will not migrate with the package.
If the same package is a part of two different connection groups, you have to indicate which connection group App-V should use. For example, you might have two packages in a connection group that each define the same registry DWORD value.
The connection group that is used is based on the order in which a package appears inside the AppConnectionGroup XML document:
The first package has the highest precedence.
The second package has the second highest precedence.
Consider the following example section:
<appv:Packages><appv:PackagePackageId="A8731008-4523-4713-83A4-CD1363907160"VersionId="E889951B-7F30-418B-A69C-B37283BC0DB9"/><appv:PackagePackageId="1DC709C8-309F-4AB4-BD47-F75926D04276"VersionId="01F1943B-C778-40AD-BFAD-AC34A695DF3C"/><appv:PackagePackageId="04220DCA-EE77-42BE-A9F5-96FD8E8593F2"VersionId="E15EFFE9-043D-4C01-BC52-AD2BD1E8BAFA"/></appv:Packages>
Assume that same DWORD value ABC (HKEY_LOCAL_MACHINE\software\contoso\finapp\region) is defined in the first and third package, such as:
Package 1 (A8731008-4523-4713-83A4-CD1363907160): HKEY_LOCAL_MACHINE\software\contoso\finapp\region=5
Package 3 (04220DCA-EE77-42BE-A9F5-96FD8E8593F2): HKEY_LOCAL_MACHINE\software\contoso\finapp\region=10
Since Package 1 appears first, the AppConnectionGroup's virtual environment will have the single DWORD value of 5 (HKEY_LOCAL_MACHINE\software\contoso\finapp\region=5). This means that the virtual applications in Package 1, Package 2, and Package 3 will all see the value 5 when they query for HKEY_LOCAL_MACHINE\software\contoso\finapp\region.
Other virtual environment resources are resolved similarly, but the usual case is that the collisions occur in the registry.
Merging identical package paths into one virtual directory in connection groups
If two or more packages in a connection group contain identical directory paths, the paths are merged into a single virtual directory inside the connection group virtual environment. This merging of paths allows an application in one package to access files that are in a different package.
When you remove a package from a connection group, the applications in that removed package are no longer able to access files in the remaining packages in the connection group.
The order in which App-V looks up a file’s name in the connection group is specified by the order in which the App-V packages are listed in the connection group manifest file.
The following example shows the order and relationship of a file name lookup in a connection group for Package A and Package B.
| Package A | Package B |
|---|---|
C:\Windows\System32 |
C:\Windows\System32 |
C:\AppTest |
C:\AppTest |
In the example above, when a virtualized application tries to find a specific file, Package A is searched first for a matching file path. If a matching path is not found, Package B is searched, using the following mapping rules:
If a file named test.txt exists in the same virtual folder hierarchy in both application packages, the first matching file is used.
If a file named bar.txt exists in the virtual folder hierarchy of one application package, but not in the other, the first matching file is used.
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