In D25546#15665, @valerio.bozzolan wrote:

I also don't get if in this part we have access to any thing related to Maniphest, ManiphestEditEngine or this kind of stuff, to just call $something->getCommentPanelPlaceholder() and have the business logic there in the specific application itself.

I fail to find anything in https://we.phorge.it/source/phorge/browse/master/src/applications/transactions/view/PhabricatorApplicationTransactionCommentView.php which would allow us to know in which Phorge application this comment field is rendered :(

In D25546#15665, @valerio.bozzolan wrote:

I also don't get if in this part we have access to any thing related to Maniphest, ManiphestEditEngine or this kind of stuff, to just call $something->getCommentPanelPlaceholder() and have the business logic there in the specific application itself.

Yeah, let me refactor this. It'll be more lines of code but way cleaner and expandable.

I see quite some potential in our downstream instance where folks do not get exposed to hints in a Form Preamble when commenting on an existing task, and will not always find and read hints in a custom red box manually added to a task description either, while this comment field placeholder will be nice automated server-side logic.

Ouch I see that receiving the engine was very complicated.

I wonder how this was used. I mean. If we have something like this:

(new PhabricatorApplicationTransactionCommentView())
  ->render();

Maybe we can add our dependency:

(new PhabricatorApplicationTransactionCommentView())
  ->setEngine($engine)
  ->render();

But this is just a stupid idea - and I'm sorry that this is becoming so time expensive

I guess another question is whether to define an abstract public function getCommentFieldPlaceholderText() in parent PhabricatorEditEngine and then add to all and every child EditEngine a default public function getCommentFieldPlaceholderText($object_phid) { return '' };. Feels cleaner to me.

and I'm sorry that this is becoming so time expensive

Nah, I see some potential in this, so I wanted to have the code properly split between general functionality implementation and per-app conditions and behavior. :)

In D25546#16489, @valerio.bozzolan wrote:

Maybe we can add our dependency:

(new PhabricatorApplicationTransactionCommentView())
  ->setEngine($engine)
  ->render();

ManiphestEditEngine does not instantiate a PhabricatorApplicationTransactionCommentView directly, it goes via the parent class PhabricatorEditEngine...

I remain unhappy with this code.

• Phorge lacks a method "give me all engines for this application".
• PhabricatorApplication offers nothing related to engines.
• PhabricatorEditEngine::getApplication() does what I want exactly the other way round: it returns the application for a given engine.
• PhabricatorEditEngine::getAllEditEngines() is confusingly named. It only returns EditEngine keys like calendar.export or maniphest.task but not actual engines or engine classes. ($engines = id(new PhabricatorEditEngineQuery())->setViewer($this->getViewer())->execute(); returns the actual engines, as already used by this code.)
• I cannot find some mapping between EditEngine keys (like maniphest.task) and either PhabricatorPHIDTypes (like ManiphestTaskPHIDType) or their TypeConstants (like TASK) either.
• getEngineClassName() exists but only in a SearchEngine/SearchQuery context, not in a EditEngine content (and I cannot find its constructor)

I still don't like the solution of using place-holder text for that; But this implementation also adds another DB access which I think is redundant.

I still don't like the solution of using place-holder text for that

I'm merely after not using more limited space on small screens (with the obvious limitation that the placeholder text must be plain text) plus once you've read the placeholder text you are done with interacting with it so it can go away once you start typing in the comment textarea field.
But if you prefer/insist that this should be rendered as a PHUIInfoView instead I can look into that - this small feature is not a hill I plan to die on. :)