Eclipse PDE headless builds modifies source dirs and MANIFEST.MF - eclipse

Question

The problem
From a number of OSGi bundles, I am creating a p2 update site using the PDE headless feature build. I don't want to copy the entire source tree (if it can be avoided) so I point the buildDirectory property to the location of my sources.
The general problem I encounter is that the PDE build sprinkles build artifacts all over the source directory (and not like all other decent build tools where the build artifacts are stored to a separate location like e.g. Maven's target folder). I can live with this but more annoying is that the PDE build modifies the MANIFEST.MF file of each compiled bundle.
The only real change to the MANIFEST.MF file is that
Bundle-Version: 1.0.0.qualifier
is rewritten to
Bundle-Version: 1.0.0.<yyyyMMddhhmm>
Apart from that, the entire file is reformatted. Of course it is correct to rewrite the file to what should end up in the assembled jars but the modified manifest should IMHO not overwrite the source manifest.
A possible solution?
Does anybody know if there is a way to tell PDE headless build to send all build artifacts to a location separate from the source files?
The nitty gritty details...
Please find below the details about my build.
How I call PDE headless
This is the command I use to call PDE headless build:
java \
-jar \
<prefix>/eclipse/3.8.1/SDK/plugins/org.eclipse.equinox.launcher_1.3.0.v20120522-1813.jar \
-application \
org.eclipse.ant.core.antRunner \
-buildfile \
<prefix>/eclipse/3.8.1/SDK/plugins/org.eclipse.pde.build_3.8.1.v20120725-202643/scripts/build.xml \
-data \
<prefix>/target/pde_workspace \
-Dbuilder=<prefix>/eclipse/3.8.1/SDK/plugins/org.eclipse.pde.build_3.8.1.v20120725-202643/templates/headless-build \
-DtopLevelElementId=org.example.myproject.feature \
-DtopLevelElementType=feature \
-DbuildDirectory=<prefix>/source \
-DbaseLocation=<prefix>/targetPlatform \
-DjavacSource=1.7 \
-DjavacTarget=1.7 \
-DcompilerArg=-g \
-DbuildLabel=output \
-DarchivePrefix=org.example.myproject \
-DbuildId=org.example.myproject.feature \
-DarchivesFormat=*,*,* - folder \
-Dp2.gathering=true \
-Dp2.build.repo=<prefix>/target/update-site \
-DskipMirroring=true \
-DcollectingFolder=<prefix>/target/tmp
My hope was that adding -DcollectingFolder would redirect all build artifacts to this folder, but it is left empty.
PDE headless documentation
The documentation for PDE headless builds is comprehensive yet somewhat imprecise. For example, for one of its many options it says:
buildType: Type of build, normally something like I, N, M, etc.
The documentation I have been able to find is this:
http://help.eclipse.org/juno/index.jsp?topic=%2Forg.eclipse.pde.doc.user%2Freference%2Fpde_builder_config.htm
Does anyone know of other documentation of the PDE headless builds?

Answer 1

You want to set the properties buildTempFolder and feature.temp.folder. I don't believe that these properties are documented anywhere.
If you are familiar with ant, the way to discover this would be to look at the build.xml file that gets generated for a plugin. In the <init> target, if buildTempFolder is set, then the build will end up setting something like
build.result.folder=${buildTempFolder}/plugins/org.example.plugin_1.2.3.201411110853`
If buildTempFolder is not set, then the default value is ${basedir}, which is the root folder of the plugin.
This build.result.folder will be the destination for most of the compiled .class files (see the <#dot> target), and the manifest will be copied there before it is modified (see the <publish.bin.parts> target. If you use customBuildCallbacks, then everything will be staged here before calling your custom callbacks.
The feature.temp.folder is similar to the buildTempFolder but affects features instead of plugins.