[tree] major and minor indices to long64, it was forgotten to change from 32bit of old interfaces

[ferdymercury]

This Pull request:

Changes or fixes:

Fixes https://its.cern.ch/jira/browse/ROOT-9028

Checklist:

• tested changes locally
• updated the docs (if necessary)

[github-actions]

Test Results

    21 files      21 suites   3d 7h 35m 42s ⏱️
 3 211 tests  3 211 ✅ 0 💤 0 ❌
65 699 runs  65 699 ✅ 0 💤 0 ❌

Results for commit 3ef0516.

♻️ This comment has been updated with latest results.

[vepadulano]

The changes look good, but we cannot merge this without a test of the use case before/after this patch

[ferdymercury]

@vepadulano @pcanal I just noticed that all the 31 bit ugly stuff was due to an outdated documentation. It's no longer the case, minor and major have now independent variables both 64-bits. So this simplifies things significantly.
See 19b0ca5

[ferdymercury]

fyi @TomasDado this PR is 'stalled' since I am not able to figure out a way to make the test pass in all platforms at the same time.

If this is urgently needed, the change 'just' in the source code could be in principle decoupled from the test in my opinion, since, even if the change is not perfect, it improves things.

[TomasDado]

Thanks for the ping @ferdymercury. Maybe it helps if I give some information to the best of my knowledge regarding this issue and ATLAS. We definitely have data periods where the eventNumber (msot commonly used for building the index) exceeds 2^32 thus we also store it as a 64 bit integer. However, I have never seen a need to build the index for data events, this this might not be an urgent issues, althought theoretically it is a problem for data. For MC, where the indexing functionality is definitely used, I am not aware of any sample exceeding 2^32 events although I think we are not that far (~1B events I have seen). Thus, I do not think the issue is urgent, but it might become urgent in the near future if we extend our MC samples.

[ferdymercury]

@pcanal I would suggest merging this PR 'as is'. The cross-platform compatibility limits of these functions have now been clearly documented, and the tests were simplified to the least common factor.

This improves the current situation, instead of using just a maximum of 32 bits, now we can use up to 52 bits, and the documentation informs you about that.