Diff mode output is empty on "large" files

[gOATiful]

Running the command:
java -classpath ./coming.jar fr.inria.coming.main.ComingMain -input filespair -location Util_before.java:Util_after.java -mode diff -output out

Returns without and error, but the fields in the created JSON are empty:

{
  "frequency": [],
  "frequencyParent": [],
  "probability": [],
  "probabilityParent": []
}

Which is not expected, since there are changes in L147 and L161.

However, removing unchanged lines from both files to a file length of about 700 lines, produces out again:

{
  "frequency": [
    {
      "c": "Class",
      "f": "1"
    }
  ],
  "frequencyParent": [
    {
      "c": "update-node_Class_Package",
      "f": "1"
    }
  ],
  "probability": [
    {
      "c": "Class",
      "f": "1.0"
    }
  ],
  "probabilityParent": [
    {
      "c": "update-node_Class_Package",
      "f": "1.0"
    }
  ]
}

This output is also not expected, since the change involves the removal of boolean literals in a function invocation.

Please find the used files attached.
used_files.zip

[monperrus]

thanks for the bug report.

Fix WIP in progress in #265

Was partially due to a bug in gumtree-spoon-ast-diff fixed in SpoonLabs/gumtree-spoon-ast-diff#313