Bar graphs: add sort_samples: false config option, also do not sort OrderedDict data

[vladsavelyev]

Fix an artefact of removing OrderedDicts #2154

The idea of the original code seems this: before Python 3.6, regular dict were randomly shuffled, so MultiQC needed to post-sort the sample list to get some reasonable order. But if the module wrapped data in an OrderedDict, it meant that the user explicitly provided the order, and it's not needed to be sorted further:

if isinstance(d, OrderedDict):
    hc_samples = list(d.keys())
else:
    hc_samples = sorted(list(d.keys()))

After Python 3.6, regular dicts keep order, so the need for that sorting has disappeared. So instead, module devs started to assume that OrderedDict is a hacky way to tell MultiQC to disable auto-sorting. Instead, we should always keep the order of passed dictionaries, and treat OrderedDicts and dicts equally (we wouldn't use OrderedDict anywhere internally anyway).

Fixes #2204

[ewels]

Happy only if:

• The order of samples is maintained between runs
• The default of order samples is alphabetical for the majority of modules where sample order is not important

It would be nice to see an example where this PR changes the output behaviour to think about this.

May need a new config option to disable alphabetical sorting? I agree that the previous behaviour with OrderedDicts was a bit hacky.

If basically nothing is changing, then happy to merge 👍🏻

[github-actions]

🚀 Deployed on https://mqc-pr-2210--multiqc.netlify.app

[vladsavelyev]

Fair points, decided to keep the order of OrderedDict inputs for legacy reasons, and also added an non-hacky way to disable sorting with the option pconfig.sort_samples which is True by default.

The order should be stable between runs.

[ewels]

Perfect, thanks!