Tab completion defects

[jblomer]

Currently, tab-completion has a few issues.

• Prompt autocomplete should treat smart pointers as pointers, not as generic classes (was [cling] Prompt autocomplete should treat smart pointers as pointers, not as generic classes #22019)
• Autocompletion of typedef
• Autocompletion of templates
• Tab completion "leaks" private members
• Tab Completion includes entities from namespaces due to GMI
• Cannot tab-complete extern "C" functions
• Tab completion and TClass::GetListOfAllPublicMethods include hidden methods from base-classes

Prompt autocomplete should treat smart pointers as pointers, not as generic classes (was #22019)

In the ROOT interactive prompt, if you have a smart pointer foo, type foo-> and hit Tab, the autocomplete function will change the -> into a . and say:

"foo" is not of pointer type. Use this operator: .

This is almost always an undesirable behavior when dealing with smart pointers, as it's far more common to want to autocomplete with the inner object's methods/fields rather than the smart pointer's own ones.

Proposed change: change the prompt behavior to treat specially unique_ptr, shared_ptr and weak_ptr (or perhaps in general all classes that define operator->?) so that it autocompletes the referenced object's methods and fields.

Autocompletion of typedefs

The ROOT prompt doesn't consider typedef/using for the tab completion. It would be nice if it did.

Reproduce in the prompt with

root [0] using FooBar = TObject;
root [1] Foo<Tab>

Forum post: https://root-forum.cern.ch/t/cling-discover-typedef-and-using-instructions/64634

Autocompletion of templates

root [0] gROOT->GetListOfFunctionTemplates()->Add(new TNamed("foobar", "foobar()"))
root [13] foob<TAB>

(was https://its.cern.ch/jira/browse/ROOT-10141)

Tab completion "leaks" private members

For the following class definition

class A {
public:
   int x; 
};
class B : public A {
private:
   using A::x;
};

the tab completion of b. of an object B b; shows x. Normally, private data members are not shown though.
(was #10535)

Tab Completion includes entities from namespaces due to GMI

TH1DModel, TProfile1DModel, TProfile2DModel, TObjectHolder, TObjectItem are in namespaces and should not be completed unless using namespace is specified.
(was https://its.cern.ch/jira/browse/ROOT-10989)

Cannot tab-complete extern "C" functions

root [1] extern "C" int funcToTestAutoComp();
root [2] int funcToTestAutoCompB(int);
root [3] funcToTestAutoCompB(

Note how funcToTestAutoComp is not seen as an option.

Tab completion and TClass::GetListOfAllPublicMethods include hidden methods from base-classes

This might be (somewhat) related to ROOT-5660.
Consider a class "CBTRefArray" inheriting from the well-known TRefArray.
In this class, I re-define GetPID:

TProcessID *CBTRefArray::GetPID(Int_t at) const { ... };

The number of arguments is different (TRefArray::GetPID has none), so the function from baseclass is hidden.

Now, I do:

root [0] CBTRefArray foo;
root [1] foo.GetPID( <TAB pressed>
TProcessID* GetPID() const
TProcessID* GetPID(Int_t at) const

So the hidden function is listed here (which I think should not be the case).
Let's try to be naïve and just call it:

root [1] foo.GetPID()
ROOT_prompt_1:1:12: error: too few arguments to function call, single argument 'at' was not specified
foo.GetPID()
~~~~~~~~~~ ^
/somepath/to/sources/CBTRefArray.h:29:2: note: 'GetPID' declared here
        TProcessID *GetPID(Int_t at) const;
        ^
root [2]

Nice error output with wonderful markup, as expected.

I actually found this issue in compiled code, where I iterate over the GetListOfAllPublicMethods() from CBTRefArray::Class() which contains both GetPID() and GetPID(Int_t) which is the same issue.
(was https://its.cern.ch/jira/browse/ROOT-6436)

[ferdymercury]

Related/ On the same topic:
https://its.cern.ch/jira/browse/ROOT-10141?jql=project%20%3D%20ROOT%20AND%20resolution%20%3D%20Unresolved%20AND%20text%20~%20%22tab%20complet%22%20ORDER%20BY%20priority%20DESC%2C%20updated%20DESC
#10535

Maybe all these issues could be merged into one "Improve Tab Completion" issue.