Add the scalar to the operand

[pingsutw]

TL;DR

Adding the scalar to the operand gives Propeller the ability to

1. Check if the input value is None
2. Compare two structured Dataset schemas
3. Compare two file paths

Type

• Bug Fix
• Feature
• Plugin

Are all requirements met?

• Code completed
• Smoke tested
• Unit tests added
• Code documentation added
• Any pending items have an associated Issue

Complete description

^^^

Tracking Issue

flyteorg/flyte#3514

Follow-up issue

NA

[codecov]

Codecov Report

Merging #427 (70bdca5) into master (0dabef7) will increase coverage by 2.55%.
The diff coverage is n/a.

❗ Current head 70bdca5 differs from pull request most recent head 9550df1. Consider uploading reports for the commit 9550df1 to get more accurate results

@@            Coverage Diff             @@
##           master     #427      +/-   ##
==========================================
+ Coverage   75.92%   78.48%   +2.55%     
==========================================
  Files          18       18              
  Lines        1458     1250     -208     
==========================================
- Hits         1107      981     -126     
+ Misses        294      212      -82     
  Partials       57       57              

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see 18 files with indirect coverage changes

[hamersaw]

@pingsutw the biggest concern here is opening up required support for union, map, collection, etc that aren't in primitive, but are in scalar. Is the plan for flytekit logic to have very specific errors saying "Unsupported type 'X' in branch conditional .." or something?

[pingsutw]

Is the plan for flytekit logic to have very specific errors saying "Unsupported type 'X' in branch conditional .." or something?

Yes, in this PR, flytekit will return an error if people use collection or map. Now, we only support primitive and none.