gen/enum: Support periods in item names

[ramprasadg]

This adds support for enum items with periods in their names.

Previously, the following enum would parse successfully but generate
invalid Go code.

enum X { foo.bar, baz }

With this change, foo.bar is treated similarly to foo_bar.

[CLAassistant]

All committers have signed the CLA.

[abhinav]

Hello! Thanks for your contribution! Before we can review this, please,

• Sign the CLA.
• Provide a descriptive PR title.
• Provide a detailed PR description that explains what this change is doing and why; the how should be self-evident from the code.
• If you're adding new behavior, add or update a test to exercise this behavior. For code generation changes, check out gen/internal/tests/thrift.

[ramprasadgopal]

@abhinav can you please have a look now?
I have added the unit tests.

[abhinav]

This looks great. Thank you!

CC @kriskowal @mh-park if you wouldn't mind taking a look as well.

[abhinav]

Actually, I just realized that this isn't something that Apache Thrift
supports. Introducing this change will encourage Thrift files that work with
ThriftRW but not with Apache Thrift.

$ cat > tmp.thrift
enum X { foo.bar, baz }
$ thrift --gen py tmp.thrift
[ERROR:/Users/abg/tmp/tmp.thrift:1] (last token was ',')
Identifier foo.bar can't have a dot.
$ thrift --gen go tmp.thrift
[ERROR:/Users/abg/tmp/tmp.thrift:1] (last token was ',')
Identifier foo.bar can't have a dot.

Can you add some background about your use case so that we can weigh the
potential issues associated with this change and possible solutions?

[ramprasadg]

@abhinav its because RTAPI thrift files use them.
looks is Android, iOS code gens unfortunately support this non standard version.

[kriskowal]

@ramprasadg We’ve had many conversations over the years about RTAPI’s enums. The road for RTAPI IDL to be welcomed into the fold of IDL that can cross-compile is to move the dot delimited name into an annotation and change the name to an identifier that will compile in other languages. This is important especially since Eats services in particular use RTAPI to translate JSON to TBinary for Go services, so the IDL needs to compile for both.

I was under the impression that there was an effort in progress to convert enum names to annotations.

[ramprasadg]

@kriskowal do you know who would be the right people to contact?
do you see a problem with this commit as an interim solution until the RTAPI effort is completed?

[abhinav]

We decided against this after all.