I'm +1 for the $SUBJECT concept, mostly because I take longer to read code where immaterial zero-initialization lines are diluting the code. A quick scan of the patch content is promising. If there's a decision to move forward, I'm happy to review it more closely.
On Wed, Jun 30, 2021 at 09:28:17AM -0400, Tom Lane wrote: > David Rowley <dgrowle...@gmail.com> writes: > > On Tue, 29 Jun 2021 at 02:15, Tom Lane <t...@sss.pgh.pa.us> wrote: > >> The primary case where I personally rely on that style is when adding a > >> new field to a struct. Currently it's possible to grep for some existing > >> field and add the new one beside it. Leaving out initializations by > >> relying on side-effects of makeNode makes that far riskier. > > > FWIW, I mostly grep for makeNode(NameOfNode) as I'm a bit mistrusting > > of if the random existing field name that I pick to grep for will > > properly showing me all the locations I should touch. > > I tend to do that too, but it's not a foolproof thing either, since > some places use random memset's for the purpose. I checked the first five matches of "git grep ' = T_'" to get a sense of code sites that skip makeNode(). Just one of those five initializes every field: recordDependencyOnSingleRelExpr() builds RangeTblEntry, subset of fields EventTriggerCommonSetup() builds EventTriggerData, full fields validateForeignKeyConstraint() builds TriggerData, subset of fields ExecBSInsertTriggers() builds TriggerData, subset of fields [many similar examples in trigger.c] ExecBuildProjectionInfo() builds ExprState, subset of fields Hence, I find we're already too inconsistent about "explicitly initialize every field" to recommend "grep for some existing field". (Two participants in the 2018 thread made similar observations[1][2].) grepping T_NameOfNode and then makeNode(NameOfNode) is more reliable today, and $SUBJECT will not decrease its reliability. [1] https://postgr.es/m/20180830045736.p3mrugcq2j367...@alap3.anarazel.de [2] https://postgr.es/m/ca+tgmoypw3y8zkofsetpvbb8avy7v7jbjmg6bme7cc+eod7...@mail.gmail.com