Problematic branches cause a crash

[lpernie]

Dear All,

When I try to load a root file (that you can find here [1]) I get the following error [2].
Usually I never had problems using the command below:
df = spark.read.format("org.dianahep.sparkroot").load("file.root")

We noted that some branches (those starting with Jet_btagSF) for instance, are visible in the TBrowser, but not in PYROOT.
I assume some mistake have been done when creating those branches.
There is any plan to be able to skip 'problematic' branches when loading a root file, instead of having a crash?

Cheers,
Luca

[1] https://www.dropbox.com/s/8yzbdvs4rbaiyf7/6214A145-5711-E811-997E-0CC47A78A42C_Friend.root?dl=0

[2]
Map(path -> /data/taohuang/HHNtuple_20180418_DYestimation/DYJetsToLL_M-10to50_TuneCUETP8M1_13TeV-madgraphMLM-pythia8/6214A145-5711-E811-997E-0CC47A78A42C_Friend.root)
Warnng: Generating dummy read for fIOBits
Traceback (most recent call last):
File "trainDY.py", line 32, in
df = spark.read.format("org.dianahep.sparkroot").load("/data/taohuang/HHNtuple_20180418_DYestimation/DYJetsToLL_M-10to50_TuneCUETP8M1_13TeV-madgraphMLM-pythia8/6214A145-5711-E811-997E-0CC47A78A42C_Friend.root")
File "/home/demarley/anaconda2/lib/python2.7/site-packages/pyspark/sql/readwriter.py", line 166, in load
return self._df(self._jreader.load(path))
File "/home/demarley/anaconda2/lib/python2.7/site-packages/py4j/java_gateway.py", line 1160, in call
answer, self.gateway_client, self.target_id, self.name)
File "/home/demarley/anaconda2/lib/python2.7/site-packages/pyspark/sql/utils.py", line 63, in deco
return f(*a, **kw)
File "/home/demarley/anaconda2/lib/python2.7/site-packages/py4j/protocol.py", line 320, in get_return_value
format(target_id, ".", name), value)
py4j.protocol.Py4JJavaError: An error occurred while calling o41.load.
: java.io.IOException: Cannot skip object with no length
at org.dianahep.root4j.core.RootInputStream.skipObject(RootInputStream.java:596)
at org.dianahep.root4j.core.RootHDFSInputStream.skipObject(RootHDFSInputStream.java:387)
at org.dianahep.root4j.proxy.ROOT.TIOFeatures.readMembers()
at org.dianahep.root4j.core.AbstractRootObject.read(AbstractRootObject.java:52)
at org.dianahep.root4j.core.RootInputStream.readObject(RootInputStream.java:466)
at org.dianahep.root4j.core.RootHDFSInputStream.readObject(RootHDFSInputStream.java:222)
at org.dianahep.root4j.proxy.TTree.readMembers()
at org.dianahep.root4j.core.AbstractRootObject.read(AbstractRootObject.java:52)
at org.dianahep.root4j.proxy.TKey.getObject(:57)
at org.dianahep.sparkroot.core.package$$anonfun$findTree$1.apply(ast.scala:1177)
at org.dianahep.sparkroot.core.package$$anonfun$findTree$1.apply(ast.scala:1166)
at scala.collection.immutable.Range.foreach(Range.scala:160)
at org.dianahep.sparkroot.core.package$.findTree(ast.scala:1166)
at org.dianahep.sparkroot.package$RootTableScan.(sparkroot.scala:97)
at org.dianahep.sparkroot.DefaultSource.createRelation(sparkroot.scala:146)
at org.dianahep.sparkroot.DefaultSource.createRelation(sparkroot.scala:143)
at org.apache.spark.sql.execution.datasources.DataSource.resolveRelation(DataSource.scala:340)
at org.apache.spark.sql.DataFrameReader.loadV1Source(DataFrameReader.scala:239)
at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:227)
at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:174)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:244)
at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:357)
at py4j.Gateway.invoke(Gateway.java:282)
at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132)
at py4j.commands.CallCommand.execute(CallCommand.java:79)
at py4j.GatewayConnection.run(GatewayConnection.java:214)
at java.lang.Thread.run(Thread.java:748)

[vkhristenko]

hey, thanks for reporting the crash!

short answer, this is because of non-forward (changed from backward...) compatible changes in ROOT 6.12 for I/O
Those have not been yet implemented here.

VK

[BenGalewsky]

I've run into this same problem. I'd like contribute a fix to this. I know Spark and Scala, but new to Root. @vkhristenko - could you point me at some clues to get me started on fixing this change to Root?

[vkhristenko]

@BenGalewsky,

the problematic part is this

>>> org.dianahep.root4j.proxy.ROOT.TIOFeatures.readMembers()

I persoanlly do not know the logic on the ROOT side (w.r.t TIOFeatures). This guy was introduced starting sometime around 6.12. the implementation on the root's side:
https://github.com/root-project/root/blob/master/tree/tree/inc/ROOT/TIOFeatures.hxx
and is being used in TTree:
https://github.com/root-project/root/blob/master/tree/tree/inc/TTree.h

i do not know how TIOFeatures changed the layout and that is exactly what needs to be done:

• figure out exactly how TIOFeatures changed the layout
• implement... (depends strongly on the 1st)