Ignoring attributes changes with a regex for non content parameter doesn't work as expected

[baurmatt]

Description of problem

• What did you do?
  Diffing two catalogs with OctocatalogDiff::API::V1.catalog_diff and ignoring the following change:

  File[/etc/snmp/snmpd.conf] =>
   parameters =>
     source =>
      - puppet:///modules/hardwarenode_base/snmpd.conf
      + puppet:///modules/hp_utilities/snmpd.conf

I've used the following ignore rule:

catalog_diff_result = OctocatalogDiff::API::V1.catalog_diff(
  {
    :logger       => logger,
    :to_catalog   => catalog_new.path,
    :from_catalog => catalog_old.path,
    :ignore       => [
      {
        type: 'File',
        title: '/etc/snmp/snmpd.conf',
        attr: "parameters\fsource=&>.*(hp_utilities|hardwarenode_base).*"
      },
    ]
  }
)

• What happened?
  It didn't ignore the change

• What did you expect to happen?
  That it would ignore the change

• How can someone reproduce the problem?
  Try to ignore a parameter beside content with an regex as described in https://github.com/github/octocatalog-diff/blob/master/doc/advanced-ignores.md#ignoring-attributes-whose-changes-are-encompassed-by-a-regular-expression

Command used and debugging output

Platform and version information

• Your OS: Ubuntu 14.04.5
• Your Ruby version: 2.4.0
• Your version of Puppet: 5.3.4
• Your version of octocatalog-diff: 1.5.2

Do the tests pass from a clean checkout?

Using the gem, so hopefully ;)

Anything else to add that you think will be helpful?

I think the problem is what's in the diff. If you add @logger.info line before https://github.com/github/octocatalog-diff/blob/master/lib/octocatalog-diff/catalog-diff/differ.rb#L298 the output is the following:

...
I, [2018-03-06T14:20:10.508543 #10136]  INFO -- : Catalogs compiled for
I, [2018-03-06T14:20:11.542122 #10136]  INFO -- : -puppet:///modules/hardwarenode_base/snmpd.conf

I, [2018-03-06T14:20:11.542181 #10136]  INFO -- : \ No newline at end of file

I, [2018-03-06T14:20:11.542208 #10136]  INFO -- : +puppet:///modules/hp_utilities/snmpd.conf

I, [2018-03-06T14:20:11.542238 #10136]  INFO -- : \ No newline at end of file

I, [2018-03-06T14:20:11.545826 #10136]  INFO -- : Diffs computed for
...

The problem seems to be the line \ No newline at end of file. If i change my OctocatalogDiff::API::V1.catalog_diff object to the following, the ignore works.

catalog_diff_result = OctocatalogDiff::API::V1.catalog_diff(
  {
    :logger       => logger,
    :to_catalog   => catalog_new.path,
    :from_catalog => catalog_old.path,
    :ignore       => [
      {
        type: 'File',
        title: '/etc/snmp/snmpd.conf',
        attr: "parameters\fsource=&>.*(hp_utilities|hardwarenode_base|No newline at end of file).*"
      },
    ]
  }
)

But this seems kind of non-intuitive, might be a good idea to automatically ignore those lines. On the other hand, in other scenarios there could be only this one line which someone wants to catch.

What do you think?