Skip to content

[ntuple][nfc] Add RNTupleProcessor release notes #23764

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
enirolf merged 2 commits into from
Oct 20, 2026
Merged

[ntuple][nfc] Add RNTupleProcessor release notes #23764

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
e929a32
[ntuple][nfc] Add RNTupleProcessor release notes
enirolf Oct 20, 2026
1e14270
[ntuple][nfc] Fix typos and add small intro
enirolf Oct 20, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 13 additions & 0 deletions README/ReleaseNotes/v642/index.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -153,6 +153,19 @@ Replace `obj.Connect(signal, "TPyDispatcher", disp, "Dispatch()")` with

* Reading a collection without its dictionary no longer crashes when the elements hold a `std::string` or a `TString`. The emulated collection proxy relocated its elements with a raw memory copy when its buffer had to grow, which corrupts an object that points into itself, such as a `std::string` using the small string optimization; the invalid pointer was then freed when the object was destroyed. Such elements are now destroyed and reconstructed at the new location instead. This affected for instance a `std::vector<std::pair<std::string,double>>` read back without a dictionary.

### RNTupleProcessor

The RNTupleProcessor is a new, standalone interface for creating *chains* (similar to TTree's `TChain`) and *joins* (similar to TTree friends) from RNTuples in a composable way, and iterating over their entries.
Until this release, it was available in the experimental namespace.
With ROOT v6.42:

* The RNTupleProcessor for single RNTuples and chained RNTuples has moved out of `ROOT::Experimental`.
They can be created with `ROOT::RNTupleProcessor::Create()` and `ROOT::RNTupleProcessor::CreateChain()`, respectively.
Processing joined RNTuples will remain available in the experimental namespace for this release, in order to address a few additional (potentially interface-breaking) improvements.
Creating an RNTupleProcessor for joins can (for now) be done by calling `ROOT::Experimental::CreateRNTupleJoinProcessor`.
* An experimental RDataFrame datasource using the RNTupleProcessor has been added.
RDataFrames can be created from an existing RNTupleProcessor by calling `ROOT::Experimental::RDF::FromRNTupleProcessor()`.

## Core

* `TClass::IsTriviallyRelocatable()` reports whether an object of a class can be moved to a new address with a raw memory copy, i.e. without running a move or copy constructor (trivial relocatability in the C++26 sense). It is backed by the new `kClassIsTriviallyRelocatable` class property, which `TInterpreter::ClassInfo_ClassProperty()` now fills in. A class the interpreter does not know about, in particular an emulated one, is conservatively reported as not relocatable.
Expand Down