[TINKERPOP-2605] Further enforce and refine null semantics

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Done
• Affects Version/s: 3.5.1
• Fix Version/s: 3.6.0, 3.5.2
• Component/s: process, test-suite
• Assignee: Stephen Mallette
• Reporter: Stephen Mallette
• Created: 24/Aug/21 11:20
• Updated: 10/Sep/21 10:24
• Resolved: 10/Sep/21 10:24

Description

A number of areas where null is used in traversals result in some odd looking errors. Identify these situations and improve them to be more user friendly. Some specific items to take care of:

hasLabel(null) // currently results in exception, should just filter
P.within(null) // TINKERPOP-2598
sum() // NPE if null is present, should ignore nulls in calculation and return null if all values are null
mean() // NPE if null is present, should ignore nulls in calculation and return null if all values are null
max() // NPE if null is present, should ignore nulls in calculation and return null if all values are null
min() // NPE if null is present, should ignore nulls in calculation and return null if all values are null
inject(null) // NPE
hasValue(null) // NPE if accidentally applied to hasValue(P), should just filter
hasKey(null) // NPE, should just filter
withSideEffect('k',null) // NPE, should just allow the assignment
g.inject(1,null).as('a') // NPE and won't allow labelling 
path() // NPE when encountering nulls

Issue Links

• relates to: TINKERPOP-2598 within(null) NPE