CHANGELOG.md

# Changelog
All notable changes to this project will be documented in this file.

Project Coordinators: Marco Clemencic @clemenci, Charles Leggett @leggett

The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).

## [v37r2](https://gitlab.cern.ch/gaudi/Gaudi/-/releases/v37r2) - 2023-11-28
Minor fixes in preparation for the next major release.

### Changed
- Deprecate no longer required `concat_alternatives` (gaudi/Gaudi!1513)
- Migrate tests to pytest and various fixes (gaudi/Gaudi!1517 gaudi/Gaudi!1519)

### Fixed
- `GaudiConfig2`: strict type checking for list properties (gaudi/Gaudi!1518)
- Fix booking of n-tuple columns with and without ranges (gaudi/Gaudi#282 gaudi/Gaudi!1522)
- Prefer `std::abs` over `abs` (gaudi/Gaudi!1516, gaudi/Gaudi!1524)
- Fix include for catch2 3.1 and above (gaudi/Gaudi!1515)
- Cleanup of `SmartRef` (gaudi/Gaudi!1512)
- Work around libstdc++ bug (gaudi/Gaudi!1514)


## [v37r1](https://gitlab.cern.ch/gaudi/Gaudi/-/releases/v37r1) - 2023-10-30
This is a minor release meant mostly to address issues with compilation on gcc 13, clang 16 and C++20.
It features as well a number of other fixes and improvements and some clean up.

As of this release I added machine readable citation instructions (see https://citation-file-format.github.io/).

### Changed
- Remove `FindTBB.cmake` to rely on the official `TBBConfig.cmake` (gaudi/Gaudi!1510)
- `genconf`: remove property type comment from Conf files (gaudi/Gaudi!1502)

### Added
- Add citation instructions and helper to prepare new releases (gaudi/Gaudi!1494)

### Fixed
- Work around issue with clang implicit instantiation in C++20 mode. (gaudi/Gaudi!1511)
- `JobOptionSvc`: use stringstream to read job options file (gaudi/Gaudi!1509)
- Fixes for gcc 13, clang 16 and C++20 (gaudi/Gaudi!1501)
- Remove name argument from GaudiConfig2 PropertySemantics (gaudi/Gaudi#275, gaudi/Gaudi!1492)
- Drop a Python 2 compatibility hack and fix handling of bool properties in GaudiPython (gaudi/Gaudi#276, gaudi/Gaudi!1507)
- Fixed unsafe floating point comparisons (gaudi/Gaudi!1490)
- `GaudiConfig2`: minor performance optimizations for Configurable (gaudi/Gaudi!1500)
- Fixed JSON counter dumps validation to ignore changes in order of entries (gaudi/Gaudi!1496)
- Support oneTBB (gaudi/Gaudi#270, gaudi/Gaudi!1495)


## [v37r0](https://gitlab.cern.ch/gaudi/Gaudi/-/releases/v37r0) - 2023-09-14
This is the first major release of Gaudi in a while. This was made necessary to be able to incorporate
a number of backward incompatible changes that have been kept in the backburner until now.

The main (backward incompatible) changes are:
- clean up and improvements to the new monitoring infrastructure
  - custom sinks have to be adapted
- drop of `LIKELY` and `UNLIKELY` preprocessor macros
  - they have been deprecated for long, but waiting for a major release to effectively
    remove the implementation
- make the subdirectory `GaudiAlg` optional
  - still enabled by default, it's not really backward incompatible, but the refactoring
    implies that some minor adaptations might be needed in downstream code

Since this a major release we took the occasion to update the versions of the hooks in
`pre-commit-config.yaml` and that caused some minor changes in the formatting.

In addition we have the usual batch of fixes and some new features.

### Changed
- Update versions in `pre-commit` hooks (gaudi/Gaudi!1415)
- Remove old warning message referring to `CMT` (gaudi/Gaudi!1486)
- Cleanup, fixes and new features around monitoring sinks (gaudi/Gaudi!1439)
- Reorganize files and refactor code to make GaudiAlg optional (gaudi/Gaudi!1444)
- Dropped (UN)LIKELY macro (gaudi/Gaudi!1227)
- Update and simplify gitlab-ci (gaudi/Gaudi!1476)

### Added
- Added support for the HepPDT vesion 3 (gaudi/Gaudi!1488)
- Implement helper class for arrays of counters (gaudi/Gaudi!1484)
- Fire ContextIncident `CONNECTED_NTUPLE_OUTPUT` when opening a ntuple file in RFileCnv (gaudi/Gaudi!1478)
- Check errors in histograms unit tests on top of bin content (gaudi/Gaudi!1480)
- Add `GAUDI_PGO` CMake options to enable builds with Profile Guided Optimizations (gaudi/Gaudi!1472)

### Fixed
- Fix missing Property name in error messages (gaudi/Gaudi#265  gaudi/Gaudi!1468)
- Fix TTree output reading in tests (gaudi/Gaudi#273  gaudi/Gaudi!1489)
- Use `inspect.signature` (if possible) instead of the deprecated `getargspec` (gaudi/Gaudi!1485)
- Never rely on default Gitlab Docker image in gitlab-ci (gaudi/Gaudi!1491)
- Fix performance of Counter destructor by using appropriate containers in Sink (gaudi/Gaudi!1477)
- Hide `RdtscClock.h` to non x86_64 builds, needed for aarch64 (gaudi/Gaudi!1479)
- Minor fix in a CMake error message (gaudi/Gaudi!1481)
- GaudiMP: few minor fixes for Python3 (gaudi/Gaudi!1473)
- Fixed clang12 warnings (gaudi/Gaudi!1471)
- Fix finally helper with C++20 (gaudi/Gaudi!1475)
- Fix build with GAUDI_USE_AIDA=OFF (gaudi/Gaudi!1474)


## [v36r16](https://gitlab.cern.ch/gaudi/Gaudi/-/releases/v36r16) - 2023-07-28
Release requested by LHCb to backport gaudi/Gaudi!1478

### Added
- Fire ContextIncident `CONNECTED_NTUPLE_OUTPUT` when opening a ntuple file in
  RFileCnv (gaudi/Gaudi!1482)


## [v36r15](https://gitlab.cern.ch/gaudi/Gaudi/-/releases/v36r15) - 2023-07-24
This release is needed so that LHCb can pick up a backward compatible version
of gaudi/Gaudi!1477.

### Fixed
- Fix performance of Counter destructor by using appropriate containers in Sink
  (adaptation of gaudi/Gaudi!1477)


## [v36r14](https://gitlab.cern.ch/gaudi/Gaudi/-/releases/v36r14) - 2023-06-19
This release features a number of minor fixes to help downstream projects
work with C++20, plus a few minor fixes.

### Changed
- Make sure `OutputStream` instances are configured with and explicit `Output`
  option (gaudi/Gaudi#262  gaudi/Gaudi!1467)

### Added
- Allow disabling of `FIXTURES_REQUIRED` for qmtests (gaudi/Gaudi!1465)
- Made more methods public in Histograms (gaudi/Gaudi!1460)
- Add support for Gaudi::Property to fmtlib (gaudi/Gaudi!1462)

### Fixed
- Fix delegation of `T == Property<T>` for C++20 (gaudi/Gaudi!1466)
- Fixed improper ordering of stops methods in Sinks (gaudi/Gaudi!1464)
- Fixed usage of histograms with integer Arithmetic (gaudi/Gaudi!1461)


## [v36r13](https://gitlab.cern.ch/gaudi/Gaudi/-/releases/v36r13) - 2023-06-05
This is a minor bugfix release needed by LHCb to pick up some additions.

The most interesting changes in this release are:
- fixes to Python code addressing flake8 reports (now flake8 is also in the pre-commit hooks)
- fixes to be able to compile with C++20
- fixes to be able to run on macOS (some usability improvements are still needed, but no blocker left)

### Changed
- Use `GAUDI_LIBRARY_PATH` instead of `LD_LIBRARY_PATH` on macOS (gaudi/Gaudi!1452)
- Cleanup `SmartRef` (in)equality comparisons (gaudi/Gaudi!1451)
- Remove unused indirection for creating new `LinkManagers` (gaudi/Gaudi!1450)
- Avoid spurious copy of `Stream` (gaudi/Gaudi!1449)
- EventContext: make constructor explicit (gaudi/Gaudi!1446)

### Added
- Add new incident `CONNECTED_INPUT` to detect opening of ROOT files for read (gaudi/Gaudi!1456)
- Add flake8 pre-commit hook (gaudi/Gaudi#263  gaudi/Gaudi!1441)
- Add specialized function to declare pytest tests (gaudi/Gaudi!1440, gaudi/Gaudi!1448, gaudi/Gaudi!1457)
- Add move constructor/assignment to `LinkManager` (gaudi/Gaudi!1447)
- Adds the ability to show the data dependencies of AlgTools (gaudi/Gaudi!1348)

### Fixed
- C++20 fixes (gaudi/Gaudi#266  gaudi/Gaudi!1455)
- Fix compiler error with fmt 10.0.0 (gaudi/Gaudi!1454)
- Fix corner case in QMT file parsing (gaudi/Gaudi!1453)
- GaudiConfig2: fix comparison of sequence properties (gaudi/Gaudi#264  gaudi/Gaudi!1445)
- flake8 fixes (gaudi/Gaudi!1443, gaudi/Gaudi!1442, gaudi/Gaudi!1438, gaudi/Gaudi!1437)
- Fix genconf on macOS (gaudi/Gaudi!1406)


## [v36r12][] - 2023-03-20
Another minor release requested by LHCb.  The main change is that now
`OutputStream` creates the output file during the *start* transition instead of
when trying to write the first selected event.  This means that output files
might be created and left empty rather than not created.  The rationale for
this change is to have a more predictable behaviour (one that does not depend
on the job details).

### Changed
- Always write output files (gaudi/Gaudi!1432)

### Added
- GaudiConfig2: add clone for Configurable (gaudi/Gaudi!1433)

### Fixed
- GaudiKernel: flake8 fixes (gaudi/Gaudi!1434)


## [v36r11][] - 2023-02-27
Just a minor update to pick up some changes that didn't make it for v36r10.

### Added
- Adds `CheckedNamedToolsConfigured` functionality (gaudi/Gaudi!1424)

### Fixed
- Fix log file messages when using `Histograming::Sink::Base` (gaudi/Gaudi!1426)
- Remove `TWebFile` access for http(s) `TURL`s and use default `TFile::Open`
  via davix instead (gaudi/Gaudi!1427)
- Update version of `isort` used in `pre-commit` (gaudi/Gaudi!1429)


## [v36r10][] - 2023-02-14
This is a small maintenance release focusing on fixing bugs. In particular we fixed a
number of issues affecting builds on MacOS.

There are a few changes that should be mostly transparent from the code point of view,
but may produce slightly different printouts.

### Changed
- Use `python3` instead of `python` (gaudi/Gaudi!1418)
- Use MessageSvc to handle ROOT messages (gaudi/Gaudi!1412)
- Switching from histogramPersistencySvc to new Sinks (gaudi/Gaudi!1401)

### Added
- Add algorithm to programmatically enable/disable perf (gaudi/Gaudi!1408)
- PluginServiceV2: allow factories to be deprecated (gaudi/Gaudi!1395)

### Fixed
- Various fixes for MacOS (gaudi/Gaudi!1422 gaudi/Gaudi!1405 gaudi/Gaudi#249)
- Fix gcc11 anonymous namespace warnings (gaudi/Gaudi!1425)
- Fix use of Boost unit test framework in AttribStringParser_test (gaudi/Gaudi!1420)
- Fixes in preparation for LCG 103 (gaudi/Gaudi!1419)
- Fixed minimal build of Gaudi and added CI test job to validate it (gaudi/Gaudi!1417)
- ProcStats: Use mutex lock to make fetch() thread safe. (gaudi/Gaudi!1410)
- Fix fmt for StatEntity for latest fmt versions (gaudi/Gaudi!1409)
- Property: remove deprecation comment on value() (gaudi/Gaudi!1416)
- Fix issue when building Gaudi with Boost 1.81 (gaudi/Gaudi#255  gaudi/Gaudi!1413)
- Make Catch2 based test compatible with Catch2 v3 (gaudi/Gaudi#252  gaudi/Gaudi!1407)
- Fix gcc12 warnings (gaudi/Gaudi!1403)


## v36r9p1 - 2023-02-03
Strictly identical to v36r9 (except for the version number), needed by LHCb for
a special deployment.


## [v36r9][] - 2022-11-21
Just some minor bugfixes and a few (mostly backword compatible) changes in behaviour.

To be noted:
- ROOT file produced by `RootCnvSvc` are now more reproducible
  (gaudi/Gaudi!1380), thanks to a special flag from
  [TFile](https://root.cern/doc/master/classTFile.html#ae82abd48570a83d8aecb2af32eaa324ea31be021b9a54c95db15121c28b69f242),
  in case of problems or for backward compatibility the new behaviour can be
  turned off with the `RootCnvSvc` property `ProduceReproducibleFiles` (dafalt
  is `true`)
- `RootCnvSvc` improves compressibility of files by using larger basket sizes
  (see gaudi/Gaudi!1381), the side effect is that one may notice al larger use
  of VMEM from the job
- we added a few missing `const` in `LinkManager` interface (gaudi/Gaudi!1386),
  but that means that downstream code might fail to build if it was relying on
  `const` instances returning pointer to non-`const` objects
- you will get a runtime error when trying to create histograms with heading or
  trailing whitespaces in titles and labels (gaudi/Gaudi!1397)


### Changed
- Create reproducible ROOT files and clean up tests (gaudi/Gaudi!1380)
- Do not allow whitespace at front or back of histogram titles or labels (lhcb/Gaudi#3 gaudi/Gaudi!1397)
- Optimise basket sizes created by `RootCnvSvc` (gaudi/Gaudi!1381)
- Avoid unneccessary work if tests are not requested (gaudi/Gaudi!1391)
- Use Gitlab CI DAG pipelines (gaudi/Gaudi!1393)
- More const-correct `LinkManager` interface (gaudi/Gaudi!1386)

### Added
- Add test build of public headers (again) (gaudi/Gaudi!1394)
- Add support for `.json` options to `Gaudi.exe` (gaudi/Gaudi!1388)
- Add output dependency checks to `AvalancheSchedulerSvc` (gaudi/Gaudi!1384)

### Fixed
- Fixes to support builds on ARM processors (gaudi/Gaudi!1396)
- Fix use of deprecated Boost headers (gaudi/Gaudi!1400)
- Fix `UnboundLocalError` in `GaudiKernel/Configurable.py` (gaudi/Gaudi!1399)
- Fix detection of platform specific reference files (gaudi/Gaudi#236  gaudi/Gaudi!1398)
- Fix access to Python binary modules from the build tree (gaudi/Gaudi#240  gaudi/Gaudi!1392)
- Fix TProfile creation in ROOT monitoring sink when SetDefaultSumw2 is used (gaudi/Gaudi!1390)
- Use actual counter type when registering to monitoring (gaudi/Gaudi!1389)
- Release the GIL when bootstrapping with `Gaudi.Application` (gaudi/Gaudi!1387)


## [v36r8][] - 2022-10-12
Minor release to pick up some fixes for ATLAS and LHCb.

This release also features some clean up and some improvements to monitoring and testing infrastructure.

### Changed
- Separated `RootHistogramSinkBase` from `RootHistogramSink` (gaudi/Gaudi!1377)
- Avoid worse-case performance issues when computing test diffs (gaudi/Gaudi!1375)
- Remove long deprecated header `CArrayAsProperty.h` (gaudi/Gaudi!1373)

### Added
- Add method to update `Monitoring::Hub::Entity` from JSON data (gaudi/Gaudi!1379)
- Implemented `HistogramArray` class to ease the use of arrays of histograms (gaudi/Gaudi!1372)
- Add execution time of `ValidateOutput` to `BaseTest` output (gaudi/Gaudi!1360)

### Fixed
- Prevent hanging on test timeout with ASan builds (gaudi/Gaudi!1383)
- DataBroker: avoid entering the same producer multiple times as scheduling dependency (gaudi/Gaudi!1382)
- Avoid deprecated `std::iterator` (gaudi/Gaudi!1371)
- Fix race condition in `ServiceManager` (gaudi/Gaudi#237  gaudi/Gaudi!1376)
- Fix test failures when `GAUDIAPPNAME` or `GAUDIAPPVERSION` are set (gaudi/Gaudi#233  gaudi/Gaudi!1374)
- Fix deprecation warnings with Boost 1.79 (gaudi/Gaudi!1370)
- Bootstrap.cpp: Relinquish Python's GIL before calling `executeRun` to allow Python algs in MT mode (gaudi/Gaudi!1369)
- Ensure `MessageSvc` and `JobOptionsSvc` are cleaned up when terminating `ApplicationMgr` (gaudi/Gaudi!1368)


## [v36r7][] - 2022-07-29
Minor release needed by LHCb to pick up some fixes.

Note that the re-write of `Gaudi::Monitoring::JSONSink` is not backward compatible.

### Changed
- New improved `Gaudi::Monitoring::JSONSink` (with support for histograms) (gaudi/Gaudi!1362)

### Fixed
- Allow calling `init()` twice on a `DataHandle` (gaudi/Gaudi#221  gaudi/Gaudi!1366)
- Add missing include of `<utility>` (gaudi/Gaudi#235  gaudi/Gaudi!1365)
- Avoid floating point exception during printing in `EventSelector` (gaudi/Gaudi!1364)
- Forward forgotten `InhibitPathes` property from `HiveWhiteBoard` to `DataSvc` (gaudi/Gaudi!1361)
- Fix check for finding PkgConfig (gaudi/Gaudi!1363)
- Replace `std::result_of_t` with `std::invoke_result_t` following its deprecation in C++17  (gaudi/Gaudi!1359)


## [v36r6][] - 2022-07-11
Same as [v36r5][], we have several small changes and fixes in this release, as well as the removal of some deprecated and unused code.

### Changed
- Modify `FetchLeavesFromFile` to use `IDataManagerSvc::traverseSubTree` (gaudi/Gaudi#232  gaudi/Gaudi!1357)
- Accumulators: drop unused Boost includes (gaudi/Gaudi#228  gaudi/Gaudi!1349)
- Use pkgconfig to find gperftools (gaudi/Gaudi#210  gaudi/Gaudi!1354)
- Delete `StatusCodeSvc` and its interface (gaudi/Gaudi!1310)
- EventIDRange c'tor: Don't reset UNDEF values to 0 (gaudi/Gaudi!1347)
- Cleanup old, unsed and deprecated code in DataHandles (gaudi/Gaudi!1337)
- Update version of Black used in pre-commit  (gaudi/Gaudi!1334)

### Added
- Allow histograms to be saved in custom directories (gaudi/Gaudi!1353)
- Support writing ROOT files with LZ4 and ZSTD compression (gaudi/Gaudi!1346)
- Include GaudiException `tag()` strings in GaudiAlg functional warning/error messages when caught (gaudi/Gaudi!1345)
- AvalancheSchedulerSvc: Print also event number if a stall is detected (gaudi/Gaudi!1339)
- Add erase method to PluginSvc Registry class (gaudi/Gaudi!1338)
- Provide diagnostic information instead of SEGV when a bound tool is disabled (gaudi/Gaudi!1330)

### Fixed
- Resolve race conditions in tests (gaudi/Gaudi#211  gaudi/Gaudi!1356)
- Improve memory footprint of `JobOptionsSvc` (gaudi/Gaudi#194  gaudi/Gaudi!1304)
- Do not use anonymous namespaces in Histograms headers (gaudi/Gaudi!1351)
- Fix for allowing full customization of Histograms (gaudi/Gaudi!1352)
- Prevent usage of histograms with wrong number of coordinates (gaudi/Gaudi#226  gaudi/Gaudi!1350)
- Fix a possible uninitialized variable warning (gaudi/Gaudi!1344)
- Fix invalid SUCCESS in `[Ts]DataSvc::retrieveEntry` (gaudi/Gaudi!1333)
- Make `Rndm::Numbers` methods const (gaudi/Gaudi!1343)
- Fix compilation with gcc12. (gaudi/Gaudi!1341)
- Fix clang warning. (gaudi/Gaudi!1340)
- Fix and deprecate histogram filling with `operator+=` (gaudi/Gaudi!1336)
- Use ofstream from std (gaudi/Gaudi!1335)
- Change `AlgResourcePool` to obey isReEntrant() (gaudi/Gaudi!1331)


## [v36r5][] - 2022-04-04
Several small changes and fixes in this release. It also features the removal of some deprecated and unused code.

### Changed
- Suppress Initialize/Finalize (mis)balance messages (gaudi/Gaudi#215 gaudi/Gaudi!1313)
- GaudiKernel: remove deprecated `setProperties` methods (gaudi/Gaudi!1311)
- StatusCode: remove deprecated checking code (gaudi/Gaudi!1309)
- Changes for LHCb super project builds (gaudi/Gaudi!1308)
- Dropped usage of `(UN)LIKELY` macro (gaudi/Gaudi!1307)

### Added
- Add Trait to write an *OpaqueView* to the TES which makes the underlying object inaccessible (gaudi/Gaudi!1318)
- Message: cleanup and add accessors for event ID (gaudi/Gaudi!1325)
- Extend `IFileAccess` interface with a `read` function (gaudi/Gaudi!1317)
- Add another `Gaudi::Functional` transformer: `SplittingMergingTransformer` (gaudi/Gaudi!1315)

### Fixed
- Remove unused lambda captures (clang warning) (gaudi/Gaudi!1326)
- Fix compilation with nlohman_json 3.10.5 (gaudi/Gaudi#220 gaudi/Gaudi!1324)
- Fix `PluginService` segfault at initialize when `LD_LIBRARY_PATH` is not defined (gaudi/Gaudi!1316)
- Add missing `front()` and `back()` to `Functional::vector_of_const_` (gaudi/Gaudi!1323)
- Fixed computation of &quot;levels&quot; in EvtStoreSvc (gaudi/Gaudi!1322)
- Remove clearing of seed at initialization (gaudi/Gaudi!1321)
- Improvements to the `Configurable` method `merge` (gaudi/Gaudi!1319)
- Fix spurious / irrelevant data race in `DataObjectHandle` and remove unused state (gaudi/Gaudi!1314)
- Remove redundant lines from Gaudi{Tuple,Histo}Alg definition (gaudi/Gaudi!1312)


## [v36r4][] - 2022-01-20
This minor release features a few bugfixes, some usability improvements and some small backward incompatible changes
that could be as well classified as bugfixes.

### Changed
- Remove unused `LinkManager::removeLink` (gaudi/Gaudi!1294)
- {Merging,Splitting}Transformer: replace vector&lt;string&gt; property with vector&lt;DataObjID&gt; (gaudi/Gaudi!1297)
- ToolBinder: prefer function pointer in constructor over pure virtual inheritance (gaudi/Gaudi!1292)
- GaudiConfig2: apply OrderedSetSemantics to `std::[unordered_]set` (gaudi/Gaudi!1298)
- Change GaudiConfig2 default semantics to use deepcopy of the default (gaudi/Gaudi#114  gaudi/Gaudi!1296)

### Added
- Add example of consuming/producing `std::shared_ptr` with `Gaudi::Functional` (gaudi/Gaudi!1303)
- Allow use of `ConfigurableUser` specializations in configuration functions (gaudi/Gaudi#213  gaudi/Gaudi!1302)
- Record the source location of `DECLARE_COMPONENT` in Python configurables (gaudi/Gaudi#203  gaudi/Gaudi!1299)
- Extend the `gaudirun.py` `GaudiConfig2` file lookup to allow full path to modules (gaudi/Gaudi#192  gaudi/Gaudi!1301)
- Add support for multiple input arguments to Merging{,Multi}Transformer (gaudi/Gaudi!1291)

### Fixed
- Fix spurious options mismatch between old and new configurables (gaudi/Gaudi#191  gaudi/Gaudi!1300)
- `IBinder::Box` call destruct with the right pointer. (gaudi/Gaudi!1293)
- Fixes for running tests with LHCb test class (gaudi/Gaudi!1289)
- Correct conversion to Root histograms in RootHistogramSink (gaudi/Gaudi#212  gaudi/Gaudi!1290)


## [v36r3][] - 2021-12-09
This is a bugfix release with a couple of changes that technically are backward incompatible
because they fix issues that might have gone unnoticed:

- gaudi/Gaudi!1265 makes the property parser throw an exception in case of problems,
  instead of silently doing nothing (see gaudi/Gaudi#163)
- `Gaudi::Accumulators` counters were copiable but not movable, which was not correct:
  they should be neither and we fixed it, but this means you cannot use them in
  vectors and the postfix `++` operator has been removed

An interesting addition in this release is also the support for getting `AlgTool`s as
arguments to the `operator()` of `Gaudi::Functional` algorithms. Although it might seem
strange at first, it allows reducing boilerplate and opens the possibility of introducing
tool wrappers that bind a tool with event or condition data, so that the fact that a tool
needs some event data is both explicit (event data has to be passed to the tool methods)
and hidden from the end user (as the wrapper takes care of the details of data passing).

After the introduction of `pre-commit` support (gaudi/Gaudi!1261) the merge request
review became more difficult as the reformatting of changed files add too much noise,
so in this release we reformatted the code with clang-format-11 for C++ and
[Black](https://github.com/psf/black)+[isort](https://pycqa.github.io/isort/) for Python
(see gaudi/Gaudi!1286).

### Changed
- Change default parsing error policy to *Exception* (gaudi/Gaudi#163 gaudi/Gaudi!1265)
- Disable move and copy semantic for the counters (gaudi/Gaudi!1258)

### Added
- Support for binding tools to event and/or conditions data (gaudi/Gaudi!1270 gaudi/Gaudi!1285)
- Add support to retrieve Tools through `Gaudi::Functional`'s call operator (gaudi/Gaudi!1268)

### Fixed
- `THistSvc`: cache `TObject` types (gaudi/Gaudi!1284)
- Re-organize `struct THistID` to avoid padding (gaudi/Gaudi!1284)
- Do not link GaudiGoogleProfiling against tcmalloc and profiler (gaudi/Gaudi!1282)
- Make sure `WorkManager.pool` is closed at exit (gaudi/Gaudi!1279)
- Improve configurables db exclusion (gaudi/Gaudi#209  gaudi/Gaudi!1280)
- Better (and working) implementation of non mergeable objects in Sinks (gaudi/Gaudi!1278)
- `genconf`: remove NaN warning (gaudi/Gaudi!1281)
- ConfigurableService: copy private tools of services (gaudi/Gaudi#208 gaudi/Gaudi!1277)
- Fix confusing stray space in printout of HiveDataBroker (gaudi/Gaudi!1276)
- Allow writing of Gaudi::Range and Gaudi::NamedRange in Gaudi::Functional (gaudi/Gaudi!1275)
- More natural syntax for histogram constructor (gaudi/Gaudi!1273)
- Fix tests for change in NetworkX 2.4 (gaudi/Gaudi!1274)
- Avoid ConfigurableUser leak (gaudi/Gaudi!1269)
- Allow entities with internal counters not implementing mergeAndRequest (gaudi/Gaudi!1267)


## [v36r2][] - 2021-10-18
This is a minor release with a bunch of bugfixes and improvements, mostly needed for LHCb test beam.

### Changed
- Use `pre-commit` to check C++ and Python formatting (gaudi/Gaudi!1261)
- Faster alg states search (gaudi/Gaudi!1250)
- Make `Gaudi::Functional` constructors more paranoid about # of inputs/outputs (gaudi/Gaudi!1249)

### Added
- Add support dumping and loading from JSON/YAML in `gaudirun.py` (gaudi/Gaudi#200  gaudi/Gaudi!1264)
- Update `Entity` to expose `mergeAndReset` method of internal object (gaudi/Gaudi!1253)
- Add sink service to dump counter info into a JSON file (gaudi/Gaudi!1248)

### Fixed
- Fix bug in bin indexing for &gt;1D Histograms (gaudi/Gaudi!1266)
- Do not use `FeatureSummary` to report found packages (gaudi/Gaudi#181  gaudi/Gaudi!1263)
- Make `BaseTest` properly handle tests which return skipped return code (gaudi/Gaudi!1262)

## [v36r1][] - 2021-09-20
This is a minor release with a bunch of bugfixes and improvements.

### Changed
- Dropped *Updater* mode for `DataHandles` (gaudi/Gaudi!1239)
- Truncate stall output on alg error (gaudi/Gaudi!1245)
- Replaced last instances of `boost::string_ref` and `boost::optional` with `std` counterparts (gaudi/Gaudi#4, gaudi/Gaudi!1244)

### Added
- Add optional bin labels to Histogram accumulators axes (gaudi/Gaudi!1235)
- Define some additional matrix types (gaudi/Gaudi!1232)
- Added TH3 support to histo to/from string conversion (gaudi/Gaudi!1226)

### Fixed
- Fix: private tool used by public tool thinks it is public (gaudi/Gaudi!1251)
- Type fixes related to `-Wconversion` (gaudi/Gaudi!1246)
- Fixes number of entries in ROOT histograms created by RootSink (gaudi/Gaudi!1240)
- Move computation of bin id from HistoInputType to Axis (gaudi/Gaudi!1236)
- Fix `scan_dict_deps.py` to not use directories (gaudi/Gaudi!1241)
- Fix clang11 warnings (gaudi/Gaudi!1247)
- Fix memory leak in `IncidentSvc` and more (gaudi/Gaudi!1238)
- Correctly group histograms in ROOT files (gaudi/Gaudi!1234)
- Extend `GaudiConfig2` configurable to match Configurables API (gaudi/Gaudi!1230)
- Optimize `TupleObj` (gaudi/Gaudi!1228)
- Use `CTest` fixtures and `--repeat` (gaudi/Gaudi!1192)
- Fixed out of date documentation of the new Histograms (gaudi/Gaudi!1229)
- Misc fixes and improvement (gaudi/Gaudi!1252, gaudi/Gaudi!1233, gaudi/Gaudi!1231)


## [v36r0][] - 2021-06-21
This is a major release of Gaudi that introduces some backward incompatible changes (mostly clean up).

### Changed
- More use of `std::string_view` (gaudi/Gaudi!1039)
- Removed unused properties in `GaudiCommon` (gaudi/Gaudi#143, gaudi/Gaudi!1138)
- Remove obsolete `IJobOptionsSvc` (gaudi/Gaudi#140, gaudi/Gaudi!1217)
- Drop `StatusCode` checking via `StatusCodeSvc` (gaudi/Gaudi!989)
- Remove unused public interface methods from `GaudiCommon` (gaudi/Gaudi!1140, gaudi/Gaudi#186, gaudi/Gaudi!1220)
- `JobOptionSvc`: remove case insensitivity (gaudi/Gaudi#155, gaudi/Gaudi!1179)
- Use TBB task_arena to replace deprecated components (gaudi/Gaudi!1067, gaudi/Gaudi!1193)
- `IClassIDSvc`: remove set/get package information (gaudi/Gaudi!1200)

### Added
- Improve unused options report from `JobOptionsSvc` (gaudi/Gaudi!1222)
- Introduced `DeprecatedDynamicDataObjectHandle` (gaudi/Gaudi!1202)
- Added `removeEntity` interface to `MonitoringHub` (gaudi/Gaudi!1208)

### Fixed
- `gaudirun.py`: Correctly handle `--all-opts` when mixing `GaudiConfig2` with old Configurables (gaudi/Gaudi#188, gaudi/Gaudi!1224)
- Doc: Add Sphinx-based Documentation (gaudi/Gaudi!1152, gaudi/Gaudi#190, gaudi/Gaudi!1223)
- Avoid double delete in `THistSvc::finalize` (gaudi/Gaudi!1221)
- Fix spurious clang warning (gaudi/Gaudi!1219)
- `has_fetch_add_v` should take a value type, not an `atomic<>`. (gaudi/Gaudi!1167)
- Fix semantics of `Gaudi::Accumulators::Counter` (gaudi/Gaudi#144, gaudi/Gaudi!1136)
- Remove newlines within fatal message for easier log grepping (gaudi/Gaudi!1215)
- Fixes for LCG 100 (gaudi/Gaudi!1214)
- `THistSvc` threading improvement (gaudi/Gaudi#179, gaudi/Gaudi!1212)
- `IncidentSvc`: handle rethrow for asychronous incidents (gaudi/Gaudi!1198)
- Fix StatusCodeFail tests when using GNU Make instead of Ninja (gaudi/Gaudi!1213)


## [v35r4][] - 2021-05-25
Minor release including gaudi/Gaudi!1210, needed for an LHCb release.

### Added
- Add a `MultiMergingTransformerFilter` (gaudi/Gaudi!1210)

### Fixed
- Fix CMake 3.20 warnigns (gaudi/Gaudi!1211)
- Replace `sys_siglist` (deprecated) with `strsignal` to allow build with newer glibc (> 2.32) (gaudi/Gaudi!1207)
- Always set TBB_LIBRARIES when TBB_FOUND (gaudi/Gaudi!1209)
- Simplify `StatusCode` compilation failure test (gaudi/Gaudi!1206, gaudi/Gaudi!1211)


## [v35r3][] - 2021-04-20
Another minor bugfix release with more fixes for ROOT 6.22 and improvements to the CMake configuration.

Here is a summary of the changes (see the [full list of changes](https://gitlab.cern.ch/gaudi/Gaudi/compare/v35r2...v35r3)).

### Changed
- Change how optional dependencies are handled in downstream projects (gaudi/Gaudi!1194)
- Remove serial task queue (gaudi/Gaudi!1195)
- Switch to latest ATLAS task precedence scenario in a test (gaudi/Gaudi!1190)
- Change `DevBuildType` to also enable `-Wsuggest-override` on clang if version >= 11 (gaudi/Gaudi!1191)

### Added
- Test algorithm with internal multithreading (gaudi/Gaudi!1196)
- Added a cardinality setting for `AtlasMCRecoScenario` (gaudi/Gaudi!1201)
- Extend the task precedence tracer for dumping dynamic graphs (gaudi/Gaudi!1189)
- Allow use of local targets instead of imported ones (gaudi/Gaudi!1186)

### Fixed
- Allow returning void in a `MergingTransformer` (gaudi/Gaudi!1199)
- Add small test and fix for GaudiPython.Bindings.iDataSvc traversal (gaudi/Gaudi!1178)
- Fix handling of properties for tuples and arrays of size 1 (gaudi/Gaudi#21, gaudi/Gaudi!1197)
- Add dynamic dependencies scan for `genreflex` dictionaries (gaudi/Gaudi#152  gaudi/Gaudi!1183)
- Improvements on Monitoring::Hub::Entity and accumulators (gaudi/Gaudi!1185)
- Suppress warnings about `nodiscard` in dictionary generation with ROOT 6.22 (gaudi/Gaudi!1182)
- Add custom pythonization callback to SmartRefVector (gaudi/Gaudi!1180)
- Fixed bug in Histogram filling (gaudi/Gaudi!1176)
- Improve support for new style CMake projects (gaudi/Gaudi!1177)


## [v35r2][] - 2021-03-10
Just a minor bugfix release with changes required for
- ROOT 6.22 (updated PyROOT/cppyy)
- modernization of CMake configuration of LHCb projects
- use of new monitoring interfaces in LHCb Online system

Here is a summary of the changes (see the [full list of changes](https://gitlab.cern.ch/gaudi/Gaudi/compare/v35r1...v35r2)).

### Changed
- Allow use of local targets instead of imported ones (gaudi/Gaudi!1186)
- Improvements on `Monitoring::Hub::Entity` and accumulators (gaudi/Gaudi!1185)
- Improve support for new style `CMake` downstream projects (gaudi/Gaudi!1177)

### Fixed
- Add dynamic dependencies scan for `genreflex` dictionaries (gaudi/Gaudi#152, gaudi/Gaudi!1183)
- Supress warnings about `__nodiscard__` attribute in dictionary generation with ROOT 6.22 (gaudi/Gaudi!1182)
- Add custom pythonization callback to `SmartRefVector` (gaudi/Gaudi!1180)
- Fixed bug in Histogram filling (gaudi/Gaudi!1176)


## [v35r1][] - 2021-01-28
This is mostly a bugfix release, with a couple of backward incompatible changes in
Python `DataHandle` class (gaudi/Gaudi!1144, gaudi/Gaudi!1159) and deprecation warnings
from `IJobOptionsSvc`, which will be dropped in v36r0 (gaudi/Gaudi#140).

Here is a summary of the [full list of changes](https://gitlab.cern.ch/gaudi/Gaudi/compare/v35r0...v35r1).

### Changed
- DataHandle: use all members for `==` and improve unit test (gaudi/Gaudi!1159)
- Deprecate use of `IJobOptionsSvc` (gaudi/Gaudi#139, gaudi/Gaudi!1156)
- DataHandle: Remove `__add__` operators (gaudi/Gaudi#146, gaudi/Gaudi!1144)

### Added
- Add support to `DataWriteHandle` for writing (partially type erased) 'views' into the TES (gaudi/Gaudi!1151)

### Fixed
- Adapt tests to a change in TFile "file not found" error message (gaudi/Gaudi!1174)
- ARM Fixes (gaudi/Gaudi!1153)
- IncidentSvc: fix ever-growing incident map (gaudi/Gaudi!1164)
- Fix CF bug arising from empty sequence (gaudi/Gaudi#135, gaudi/Gaudi!1106)
- Re-enabled the installation of the `PartPropSvc` auxiliary files (gaudi/Gaudi!1172)
- Make iteration ordering predictable (gaudi/Gaudi!1169)
- StatusCode tweaks (gaudi/Gaudi!1171)
- GaudiToolbox: Fix generated `__init__` files to handle symlinks (gaudi/Gaudi!1170)
- Check result of `dynamic_cast<>` for null before dereferencing (gaudi/Gaudi!1168)
- Fix build instructions (gaudi/Gaudi#159, gaudi/Gaudi#161, gaudi/Gaudi!1162)
- Resolve "GAUDI_GENCONF_NO_FAIL option not working" (gaudi/Gaudi#160, gaudi/Gaudi!1161)
- Fix clang 10 warnings (gaudi/Gaudi!1166)
- Fix MacOS compilation (gaudi/Gaudi!1158)
- Do not set `Python_FIND_STRATEGY` (gaudi/Gaudi#157, gaudi/Gaudi!1157)
- Property: Catch all parsing errors (gaudi/Gaudi!1165)
- simplify `iid_cast` implementation (gaudi/Gaudi!1154)
- Monitor Algorithm instance misses (gaudi/Gaudi!1148)
- Fix GaudiPython classes (follows up gaudi/Gaudi!1116) (gaudi/Gaudi!1155)
- Fix py-formatting of exec (gaudi/Gaudi!1160)
- Fix Algorithm destructor invocation in multithreading applications (gaudi/Gaudi#150, gaudi/Gaudi!1149)

## [v35r0][] - 2020-11-10
This version features a complete rewrite of the CMake configuration. See gaudi/Gaudi!986 and gaudi/Gaudi!922 for details.

Here is a summary of the [full list of changes](https://gitlab.cern.ch/gaudi/Gaudi/compare/v34r1...v35r0).

### Changed
- Complete rewrite of CMake configuration in *modern* CMake (gaudi/Gaudi!986, gaudi/Gaudi!922)

### Fixed
- Restore use of `GENREFLEX_JOB_POOL` (gaudi/Gaudi#151, gaudi/Gaudi!1150)
- Improve resilience of CI build jobs (gaudi/Gaudi#149, gaudi/Gaudi!1146)
- Fix test checking the wrong thing (gaudi/Gaudi!1142)
- Resolve "test wrapper report logic is the wrong way around" (gaudi/Gaudi#3, gaudi/Gaudi!1132)
- Ignore relative paths when generating the run script (gaudi/Gaudi#147, gaudi/Gaudi!1145)
- Fix QMTest reference filename lookup (gaudi/Gaudi!1143)

## [v34r1][] - 2020-10-16
This is mostly a bugfix release meant as a checkpoint before the tag of [v35r0][]
(which will introduce the refactoring of the CMake configuration, gaudi/Gaudi!986, gaudi/Gaudi!922).

We anyway have some important changes:
- update of physics constants to match the current release of CLHEP (gaudi/Gaudi!1101)
- a new way of dealing with monitorable quantities like counters and histograms (gaudi/Gaudi!1112, gaudi/Gaudi!1113, gaudi/Gaudi!1129)
- `DataObjectHandleProperty` renamed to `DataHandleProperty` (gaudi/Gaudi!1091)
- allow services to *autoretrieve* tool handles (gaudi/Gaudi!1124)
- new helper class to recursively renounce inputs from all tools of an algorithm or tool (gaudi/Gaudi!1118, gaudi/Gaudi!1130, gaudi/Gaudi!1135)

Here is a summary of the [full list of changes](https://gitlab.cern.ch/gaudi/Gaudi/compare/v34r0...v34r1).

### Changed
- Autoretrieve `AlgTools` in `Services`, check for data deps (gaudi/Gaudi!1124)
- Change `DataObjectHandleProperty` to `DataHandleProperty` (gaudi/Gaudi!1091)
- Update units and constants (gaudi/Gaudi!1101)
- Deprecate `put` with a plain pointer as argument (gaudi/Gaudi!1086)

### Added
- Add helper class to renounce recursively inputs from all tools of an algorithm or tool (gaudi/Gaudi!1118, gaudi/Gaudi!1130, gaudi/Gaudi!1135)
- New monitoring facility for counters and histograms (gaudi/Gaudi!1112, gaudi/Gaudi!1113, gaudi/Gaudi!1129)
- Messages: Refine source field truncation (gaudi/Gaudi!1125)
- DataObjID: Add accessor for class name (gaudi/Gaudi!1126)

### Fixed
- Fixes for new ROOT/cppyy (gaudi/Gaudi!1116)
- Resolve "Use of (private) `ToolHandles` may trigger the configuration of spurious public tools" (#141, !1131)
- Fixes for clang builds (gaudi/Gaudi!1121)
- Add test reference files for AVX2/AVX512 builds (gaudi/Gaudi!1122)
- Avoid output file conflict in `MetaDataSvc` test (gaudi/Gaudi!1123)
- Use Boost filesystem instead of std::fs with clang 10 (gaudi/Gaudi!1120)
- Tweak leak sanitizer suppressions for Cling, XrootD and TStreamerInfo with LCG97a (gaudi/Gaudi!1104)
- IUpdateManagerSvc: do not specify unnecessary template arguments (gaudi/Gaudi!1090)
- Update some python examples to python 3 syntax (gaudi/Gaudi!1088)
- Test for the scheduler hang on alg exceptions (gaudi/Gaudi!979, gaudi/Gaudi!1078, gaudi/Gaudi!1107)
- Check build warnings in GitLab CI  (gaudi/Gaudi!1109)
- Remove deprecation warnings on old `IJobOptionsSvc` (gaudi/Gaudi!1114)
- Explicitly flush standard output in `MessageSvc::finalize()` (gaudi/Gaudi!1117)
- Use `Gaudi/Property.h` instead of `GaudiKernel/Property` (gaudi/Gaudi!1105)
- Algorithm state profiling (gaudi/Gaudi!1072)

## [v34r0][] - 2020-08-04
This is a release meant to introduce a major rewrite of the *Job Options Service*, as described in the merge request gaudi/Gaudi!577, plus, of course, some fixes.

### Changed
- Bump version to v34r0 (gaudi/Gaudi!1096)
- Redesign of job options management (gaudi/Gaudi!577, gaudi/Gaudi#105)
- Re-apply gaudi/Gaudi!1064: Isolate sub-slot data from the parent slot (gaudi/Gaudi!1095)

### Added
- Add CopyInputStream (gaudi/Gaudi!1077, gaudi/Gaudi#102)

### Fixed
- FMT Library Usage Improvement (gaudi/Gaudi!1103)
- Minor fixes for Clang 10 build, adapt BinaryTagUtils to allow compiler version >10 (gaudi/Gaudi!1097)
- Do not tinker with output file names in GaudiMP (gaudi/Gaudi!1098)
- Add support for special LCG versions (gaudi/Gaudi!1099)
- Fix Python 3 compatibility issues (gaudi/Gaudi!1102, b87519600879cde3be7694d9fd7567c6efd8db1c)
- Protect messages in event loop (gaudi/Gaudi!1100)

## [v33r2][] - 2020-06-19
This is a bugfix release with just a couple of minor backward compatible improvements.

We also updated the LCG baseline version to [LCG 97a](http://lcginfo.cern.ch/release/97a/) (ROOT 6.20/06).

This is the last release with the legacy CMake configuration. From the next release (v34r0)
we will use a modern CMake configuration (see gaudi/Gaudi!922 and gaudi/Gaudi!986 for details).

### Added
- Improve event context extension management (gaudi/Gaudi!1080)
- Introducing Set-semantics (gaudi/Gaudi!1066)
- Make gitlab use cpp syntax highlighting for icpp files (gaudi/Gaudi!1057)

### Fixed
- Fixes for ROOT master (gaudi/Gaudi!1071)
- Use fmtlib instead of `boost::format` (where possible) (gaudi/Gaudi!1046, gaudi/Gaudi#112)
- Conditions alg test, with stall debug info (gaudi/Gaudi!1092)
- Make sure the TES is cleaned by `EventLoopMgr` before finalize (gaudi/Gaudi!1082, LHCBPS-1850)
- Fix race condition between tests (gaudi/Gaudi!1074)
- Fix propagation of `StopIteration` exception (gaudi/Gaudi!1093, gaudi/Gaudi#129)
- Update HiveDataBroker to use C++20 ranges if available. (gaudi/Gaudi!1089)
- Fixes for C++20 (gaudi/Gaudi!1085)
- Fix thread-safety problem in GaudiHandle (gaudi/Gaudi!1084)
- Misc. sanitiser improvements (gaudi/Gaudi!1081)
- Make `GaudiHandleArray.__str__` consistent with `GaudiHandle.__str__` (gaudi/Gaudi!1070)
- Fix trivial typo in message (gaudi/Gaudi!1087)
- `GaudiConfig2`: fix unpickling of derived Configurables (gaudi/Gaudi!1076, gaudi/Gaudi#124)
- Remove data flow dumps or make them configurable (gaudi/Gaudi!1075)
- Change `StatusCode::orThrow` so that the return value can be ignored (gaudi/Gaudi!1073, gaudi/Gaudi#118)
- Fix bugs in `ThreadPoolSvc` (gaudi/Gaudi!1068)
- Sequence semantics update (gaudi/Gaudi!1069)
- Remove now unused `ATLAS_GAUDI_V21` and `HAVE_GAUDI_PLUGINSVC` definitions (gaudi/Gaudi!1062)
- Few fixes to `GaudiConfig2` (gaudi/Gaudi!1061)
- Fix compatibility with C++ GSL 3 (gaudi/Gaudi!1063, gaudi/Gaudi#121)
- Consolidate and optimize scheduling of blocking tasks (gaudi/Gaudi!1051)
- Do not run public headers build test on generated headers (gaudi/Gaudi!974)
- Add array `operator<<` into `SerializeSTL.h` (gaudi/Gaudi!1049)
- Dereference instead of `operator*` in `get_from_handle` to enable `Gaudi::Ranges` in `MergingTransformer`s (gaudi/Gaudi!1047)
- Fixes for `GetHostBinaryTag` (gaudi/Gaudi!1058)
- Remove unused capture of `this` in `MultiTransformerFilter` (gaudi/Gaudi!1059)
- Fix deprecated copy constructor warning in `StreamBuffer::ContainedLink` (gaudi/Gaudi!1060)
- `AlgExecStateSvc`: require minimum state size to be 1 (gaudi/Gaudi!1055)
- `IncidentSvc`: improve error reporting (gaudi/Gaudi!1054)
- Remove mention of deprecated `tbb::recursive_mutex` (gaudi/Gaudi!1053)

## [v33r1][] - 2020-03-23
This release contains multiple fixes and some ABI changes, in particular:
- `StatusCode` values not checked now produce a compile time warning.
- some interfaces have been changed to accept `std::string_view` instead of `const std::string&`

By default, Gaudi now uses LCG 97 (ROOT 6.20/02).

### Changed
- Removed `FindXercesC.cmake` now that new versions of Xerces are integrated with CMake (!1048)
- Add `[[nodiscard]]` attribute to `StatusCode` (!763)
- Use local memory pool in EvtStoreSvc (!1026)
- Deprecate use of `AnyDataHandle` (!1029)
- Cleanup some string handling & remove long deprecated functions (!1016)
- confDB2: Use 'PublicToolHandle', 'PrivateToolHandle' and 'ServiceHandle' instead of GaudiHandleBase as cpp_type (!1034)

### Added
- Add options to EvtStoreSvc to restrict registering addresses (#84, !1032)

### Fixed
- Make formatting check more stable and fast (!1050)
- Fix propagation of `GaudiSequencer` `RootInTES` (#94, !990)
- Fix handling of const vector in `DataObjectHandle` for `MergingTransformer` (!1045)
- Minor fixes to build on MacOS (!1044)
- Avoid explicit call to `EnableAutoLoading` for ROOT > 6.18 (!1036)
- Use PyROOT nullptr instead of None (1035)
- Support `DataObjectHandle<Gaudi::NamedRange_<T>>` (!1043)
- AlgExecStateSvc: Remove a fatal message and minor cleanups (!1037)
- Improve memory management in `ParticlePropertySvc` (!1040)
- JobOptionSvc: Fix DUMPFILE option (!1041)
- Resolve "GaudiConfigDB2: Fragile handling of templated components" (#115, !1042)
- Prefer `std::scoped_lock` over `lock_guard` (!1030, !1038)
- Reduce dynamic allocation in `GaudiKernel/Time.h` (!1033)
- Allow legacy algorithms to work with LHCb condition handles (!1031)
- Fix Cling warnings when using `GaudiPython::Helper` struct (!1028)
- Define a module `__spec__` for Configurables (!1027)
- clang requires -ffp-contract=fast with -mfma to actually enable FMA instructions (!1022)
- genconf: Fixing the handling of NAN (!1025)

## [v33r0][] - 2019-12-16
This major release of Gaudi contains additions, improvements and fixes, but most of all it adds
the agreed on copyright statement and license:

> © 1998-2019 CERN for the benefit of the LHCb and ATLAS collaborations,
> Apache version 2 license

Among the new features I'd like to highlight:
- new Python Configurables implementation (!721)
- experimental `Gaudi::Accumulators::Histogram<...>` (!1020)
- `StatusCode::{andThen|orElse|orThrow}` chaining functions (!988)

### Changed
- Enable sse 4.2 by default for clang >= 6.0 (!1019)
- Use gcc9 in Gilab-CI builds (!1013)
- Remove begin/endRun methods (!1008)
- Make `HistogramPersistencySvc` a little quieter (!992)
- Reorganization of Counters headers (!1006)
- Add new `StatusCode` category to return *filter passed* states from functional algorithms (!981)
- Use `xenv` 1.0.0 if not available from the system (!984)
- Remove const-incorrect `ToolHandle`s exception for ATLAS (!978)

### Added
- Set Gaudi copyright and license (!1018)
- Add experimental support for histograms as counters (!1020)
- Add detection of strongly connected components in the data flow precedence rules (!998)
- Debug output for a stall expecting conditions data (!994)
- Add PRG validators for detection of unconditional "editing" of data objects (!980)
- Prototype for a renewed Python Configurables implementation (!721)
- Add helpers to chain `StatusCode` dependent executions (!988)
- Update `THistSvc` to support `TEfficiency` (!1011)
- Support bulk increment of `BinomialAccumulator` (!999)

### Fixed
- `genconf`: fix quoting of strings containing quotes (!1023)
- Ignore unicode decode errors in test stdout (!1021)
- Do not use `xenv` from LCG (!1005)
- Properly escape strings with embedded quotes in `Gaudi::Utils::toStream` (!1012)
- Detect ROOT C++ standard from `ROOTConfig.cmake` (!985)
- Adjust clang warning suppression pragmas in `Transformer.h` (!1014)
- Improve scheduler performance with fewer calls to updateState (!870)
- `Gaudi::Functional`: Add possibility to query input/output location by type (!1009, !1015)
- Enable `Gaudi::Functional::Transformer<Result(const EventContext&)>` (!1007)
- More precise message for multiple algorithms having the same output in `HiveDataBroker` (!1003)
- Add flag to turn on/off use of `std::filesystem` (!987)
- `IoComponentMgr`: Only release components during finalize (!1004)
- Allow calling `f(std::string_view)` with a `Gaudi::Property<std::string>` (!1002)
- Specify file encoding when reading (!1000)
- Suppress printout of unused `MsgCounter` instances (!996)
- Do not print `SequencerTimerTool` header in finalize if there are no timing results (!997)
- Support for latest TBB and fixes for C++GSL and Range-v3 (!982)
- Fixes for "defects" detected by Coverity (!939)

## [v32r2][] - 2019-09-27
This is mostly a bugfix release, but there are nonetheless a couple of
important changes:
- now Gaudi can be used with Python 3 (#56)
- the `IAsyncEventProcessor`experimental interface introduced in v32r0 (!878)
  has been replaced with `IQueueingEventProcessor` (!966)
- it's now possible to get type information from Python version of `DataHandle`s

### Changed
- Replace `IAsyncEventProcessor` with `IQueueingEventProcessor` (!966)

### Added
- GaudiKernel `instructionsetLevel`: Add additional AVX512 levels (!954)
- Add Python 3 support (#56, !875, !975, #88, !976)
- Add vecwid256 microarchitecture option to enable `-mprefer-vector-width=256` (!965)
- Add type information to Python representation of `DataHandle`s (!951)

### Fixed
- Backward compatible interface of `IAlgorithm` for `GaudiPython` (#75, !977)
- Misc fixes for `GaudiMP` (#87, #75, !973)
- Remove unneeded change in refactoring of TES handling (#70, !971)
- Various ToolHandleArray bug fixes (!960)
- Functional ranges v3 0.9.x warning suppression (!968)
- Fix clang `-Wpotentially-evaluated-expression` warning (!970)
- Switch from Boost test minimal (deprecated) to single header variant (!948)
- Fixes for MacOS (!956)
- Make `ContainedObject` assignment consistent with copy construction (!967)
- `THistSvc::io_reinit`: Handle case of empty new filename (!959)
- `EventSelector` - Always set context ptr to null on release (!961)
- Minor improvements to sanitizers (!955)
- `ChronoStatSvc` - Clear maps in finalize (!958)
- Minor updates to `Gaudi::Functional` implementation (!952)
- `THistSvc`: Fix crash in MP if root file already exists (!949)
- Fix gcc9 warnings (!962)

## [v32r1][] - 2019-07-18
Bugfix release, with some backward compatible changes, mostly meant to pick up
[LCG 96](http://lcginfo.cern.ch/release/96/) and [ROOT 6.18/00](https://root.cern.ch/content/release-61800).

**Note**: Because of the updated version of Boost in LCG 96, you should use a recent version of CMake (>= 3.14).

### Changed
- Add algorithm name to warning in `HiveDataBroker` (!923)
- Make `Configurable.getGaudiType` a `classmethod` (!929)
- Prefer `xyz_v<T>` over `xyz<T>::value`, and `xyz_t<T>` over `typename xyz<T>::type` (!925)
- Prefer `std::{variant,optional}` over `boost::{variant,optional}` (!926)

### Added
- Specify `JOB_POOL` for `genreflex` custom commands (!933)
- Add an example `MergingTransformer` algorithm (!934)
- Add loop unroll hint macros to `GaudiKernel/Kernel.h` (!931)
- Add `MsgCounter` (!921)
- Introduce a `MergingMultiTransformer` (!901)

### Fixed
- Removed a few unused `.cpp` files (!945)
- Print counters in Gaudi::Algorithm::finalize (!943, !946, !947)
- Make asynceventprocessor tests more stable (!940)
- Small fixes to toolchain (!938)
- Use the `AlgContext` guard constructor without `EventContext` for single thread (!973, #72, #73)
- Hide spurious warning from `clang-8` (!941)
- Check that the `clang-format` command found can be executed (!935)
- Improve scheduler stall debug output (!930)
- Fix `CMake` modules test on special architectures (!927)
- Fix handling of strings with quotes in properties (!919)
- Remove reference to removed `gaudimain.runSerialOld` (!918)
- Restore backward compatibility after !878 (!917)
- Revert !869: *Create a queue for all schedule-able algorithms* (!924)
- Add `GaudiKernel` linkage to Counters unit test (!920)
- Misc. sanitizer fixes (!916)
- Fix `distcc`/`icecc` support (!911)
- Made the `LibLZMA` dependency in `GaudiKernel` optional (!909)
- `GaudiKernel`: check *likely* macros before defining them (!912)
- Fix `IOpaqueAddress` lifetime in `EvtStoreSvc` (!914)

## [v32r0][] - 2019-05-18
This release features many fixes and improvements, but also a few backward incompatible changes:
- removed  `GaudiGSL` package (in preparation for the licensing under Apache 2) (!879)
- change of `IEventProcessor` interface (!877)
- change (const correctness) of custom containers interfaces (!896)
- removed a few unused components: `HLTEventLoopMgr` (!876), `AlgErrorAuditor` (!874)
- drop support for Python *custom event loop* in `gaudirun.py` (!878)

Among the various additions you can find:
- `Counter`-based timers (!787)
- example of an interface for accessing conditions, which require experiment specific implementation (!838)
- a new interface (`Gaudi::Interfaces::IAsyncEventProcessor`) to allow decoupling of
  the main thread from the event processing thread(s) (!878)
- a simplified application steering class (`Gaudi::Application`) (!878)

### Changed
- Update `clang-format` to 8 (!872)
- Factor TES path related code out of `GaudiCommon` (!904)
- More explicit management of `EventContext` in `IEventProcessor` (!877)
- Small clean up in `EventLoopMgr` implementations (!876)
- Remove `GaudiGSL` (!879)
- Do not return non-const pointers to elements of const containers (!896)
- Drop backwards compatibility code (!883, !900)
- `HiveDataBroker`: throw exception in case of same output locations in two different algorithms (!858)
- Delete `AlgErrorAuditor` (!874)
- `PrecedenceSvc`: demote 'Verifying rules' message to debug (!873)
- Replace `boost::string_ref` with `std::string_view` (!859)

### Added
- Add optional extension of `EventProcessor` for asynchronous processing (!878)
- Add example of `ConditionAccessorHolder` implementation for integration in Functional (!838)
- Bits for the cross-experiment study on heterogeneous workflows (!828)
- Generalize `Gaudi::Functional` to support LHCb-style conditions handles (!899)
- Add a synthetic performance stress test for the scheduler (!865)
- New Minimal Event Store: `EvtStoreSvc` (!882)
- Add Counter-based timers (!787)
- Add support for `Gaudi::Algorithm` as base class of `Functional` algorithms (!897)
- Create a queue for all schedule-able algorithms (!869)
- Add support for specific architectures in BINARY_TAG (!853)
- Add `getIfExits` for `DataHandle`s with `AnyDataWrapper` (!854)
- Add support for `std::chrono::duration` in counters (!849)
- Add the possibility to ask for Mode in python data handle property (!845)

### Fixed
- Tweaks to `Gaudi::Functional` (!903)
- `HiveDataBroker`: Improve error message when unknown requested input (!906)
- Avoid copy of `EventContext` in `Gaudi::Utils::AlgContext` (!902)
- Reverse order of tbb `task_scheduler_init` and `global_control` (!895)
- Make `StatusCodeSvc` thread-safe (!885)
- `ThreadPoolSvc`: prefer `std::unique_ptr` (!889)
- Ensure thread termination tools only run in initialized threads (!887)
- Updates for MacOS and clang (!888, !894, !893)
- Enable `std::iterator_traits<vector_of_const_<T>::iterator>` (!855)
- Fix `MessageSvc::reinitialize` (!871)
- Fixes to `EventIDRange` (!860)
- `ApplicationMgr`: Call all state transition for `MessageSvc` and `JobOptionsSvc` (!866)
- Fix tunneling of CF decisions to inactive graph regions in multi-parent configurations (!863)
- Use `[[fallthrough]]` attribute instead of the _fallthrough_ comment (!862)
- Restructure PRG sources and add visitor for Concurrent/Prompt CF inconsistency detection (!861)
- Sort data dependencies in `HiveDataBroker` debug printout (!868)
- Avoid displaying unused Binomial counters (!830)
- Python 2 & 3 compatibility (!832, !852)

## [v29r5][] - 2019-03-06
This is a bugfix release only to fix a warning with the most recent version of
CMake (3.13), see the changes on
[Gitlab](https://gitlab.cern.ch/gaudi/Gaudi/compare/v29r4...v29r5).

## [v31r0][] - 2019-02-11
The main reason for this major release is to the change of the `Algorithm` base
class with a re-entrant `execute` method (#47, !703). For backward compatibility the
base class for algorithms is `Gaudi::Algorithm`, while the name `Algorithm` in
the top level namespace is used for a backward compatible implementation. This
change also required a backward incompatible change in the `IAlgorithm`
interface, so some code may require adaptation.

We also took the occasion to update the version of `clang-format` we use from
3.9 to 7, and to switch Python formatting from `autopep8` to `yapf` (!788).
Because of the differences (fixes and new features) in the versions of
`clang-format`, we also updated the style rules.