Junos: handle empty dhcp-relay server-groups

[anothermattbrown]

No description provided.

[batfish-bot]

This change is 

[dhalperi]

Reviewed 4 of 4 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @anothermattbrown and @arifogel)

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projects/batfish/src/main/antlr4/org/batfish/grammar/flatjuniper/FlatJuniper_forwarding_options.g4 line 82 at r1 (raw file):

fod_server_group
:
   SERVER_GROUP name = junos_name (address = ip_address)?

generally, would prefer new child rule with enter/exit. better than ? and complicated logic in extractor.

it's not striclty necessary, but so much of our maintainability (and parser recovery) pain is from not doing this kind of thing.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 72.53%. Comparing base (934f071) to head (6f0e214).

❗ Current head 6f0e214 differs from pull request most recent head 92de06c

Please upload reports for the commit 92de06c to get more accurate results.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9052      +/-   ##
==========================================
+ Coverage   72.52%   72.53%   +0.01%     
==========================================
  Files        3324     3324              
  Lines      169743   169743              
  Branches    19926    19927       +1     
==========================================
+ Hits       123105   123128      +23     
+ Misses      37478    37455      -23     
  Partials     9160     9160              

Files	Coverage Δ
...fish/grammar/flatjuniper/ConfigurationBuilder.java	68.40% <100.00%> (+0.37%)	⬆️

... and 3 files with indirect coverage changes

[anothermattbrown]

Reviewable status: 2 of 5 files reviewed, all discussions resolved (waiting on @arifogel and @dhalperi)

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projects/batfish/src/main/antlr4/org/batfish/grammar/flatjuniper/FlatJuniper_forwarding_options.g4 line 82 at r1 (raw file):

Previously, dhalperi (Dan Halperin) wrote…

generally, would prefer new child rule with enter/exit. better than ? and complicated logic in extractor.

it's not striclty necessary, but so much of our maintainability (and parser recovery) pain is from not doing this kind of thing.

done

[dhalperi]

Reviewed 3 of 3 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @arifogel)