[SalesForce] Deploy custom labels with Ant

I have not been able to replicate this error. In a dev org I created an empty Permission Set with the User License set to none. I then retrieved it via Ant, deleted it from the org via the UI and then deployed it back via Ant.

My package.xml:

<?xml version="1.0" encoding="UTF-8"?>
<Package xmlns="http://soap.sforce.com/2006/04/metadata">
    <types>
        <members>*</members>
        <name>PermissionSet</name>
    </types>
    <version>26.0</version>
</Package>

My permission set's XML:

<?xml version="1.0" encoding="UTF-8"?>
<PermissionSet xmlns="http://soap.sforce.com/2006/04/metadata">
    <label>GlobalTest</label>
    <userPermissions>
        <enabled>false</enabled>
        <name>ActivateContract</name>
    </userPermissions>
    <!-- All userPermissions were false; snipped for brevity -->
    <userPermissions>
        <enabled>false</enabled>
        <name>ViewSetup</name>
    </userPermissions>
</PermissionSet>

Perhaps you have some permission that is conflicting?

First, you need to ensure your package.xml contains at least what you are deploying. It may contain more, but not less.

<types>
    <members>Class1</members>
    <members>Class2</members>
    <members>Class3</members>
    <name>ApexClass</name>
</types>

UPDATE: It is even easier to do this:

<types>
    <members>*</members>
    <name>ApexClass</name>
</types>

Next, setup an ant target in your build.xml which looks something like this:

<target name="QADeployClass1And2">
    <delete file="deploy.zip"/>
    <zip destfile="deploy.zip">
        <fileset dir="src" includes="classes/Class1.*"/>
        <fileset dir="src" includes="classes/Class2.*"/>
        <fileset dir="src" includes="package.xml"/>
    </zip>
    <sf:deploy zipFile="deploy.zip" allowMissingFiles="true"
        username="user@org.com.qa" password="**********" 
        serverurl="https://test.salesforce.com"/>
    <delete file="deploy.zip"/>
</target>

When you run this target you will deploy only Class1.cls and Class2.cls. I also find it useful to place the username, password and serverurl on the target so that I can use a different ant target for each target org without having to switch out the build.properties file.

I use the zipfile approach (1) because this allows me to easily and centrally control which files go into the payload. If you wish to use a folder with deployRoot you need to make a temporary folder and copy in the files you need:

<target name="deploy1">
    <delete>
        <fileset dir=".\deploy\classes" includes="**/*.*"/>
    </delete>
    <copy file="deploy\package1.xml" tofile="deploy\package.xml"/>
    <copy todir=".\deploy\classes">
        <fileset dir=".\src\classes\" includes="Class1.*"/>
        <fileset dir=".\src\classes\" includes="Class2.*"/>
    </copy>
    <sf:deploy allowMissingFiles="true" username="${sf.username}" password="${sf.password}" serverurl="${sf.serverurl}" deployRoot="deploy"/>
</target>

In this example you could setup package1.xml to only include the files you want to deploy and it will overwrite package.xml when you run this ant target thus making allowMissingFiles="true" superfluous.