SERVER-10626 $add projection supports arrays of numbers

[astral303]

Adds nested arrays if provided. Retains nullish behavior if null is part of input.

[kangas]

Hi Oleg,

Thank you for creating a SERVER ticket as requested in our CONTRIBUTING.rst document. Have you also signed the contributor's agreement at http://www.mongodb.com/contributor ? I need this before I can hand a pull request off for review.

Also, I noticed that your pull request is against the v2.4 branch. You will need to rebase this against our master branch and resubmit. It does not currently apply cleanly against master:

######################################################################## 100.0%
Applying: $add projection supports arrays of numbers. SERVER-10626
error: patch failed: src/mongo/db/pipeline/expression.cpp:345
error: src/mongo/db/pipeline/expression.cpp: patch does not apply
error: patch failed: src/mongo/db/pipeline/expression.h:325
error: src/mongo/db/pipeline/expression.h: patch does not apply
Patch failed at 0001 $add projection supports arrays of numbers. SERVER-10626

Thank you for contributing to MongoDB!

[kangas]

Oleg, I see that you signed the contributor's agreement. Thanks! I'll wait for this to be rebased against master.

[astral303]

Hi Matt, yes, I will have this rebased soon! We are running 2.4, but I understand that this kind of change is too drastic for 2.4. Thanks!

[benety]

https://jira.mongodb.org/browse/SERVER-10626

[benety]

Hi Oleg,

Based on @andy10gen's feedback in the SERVER ticket, I'm closing this pull request but I will leave the SERVER ticket open for further discussion and future pull requests.

Regards,
Ben