So, to be absolutely, 100% clear:
The OP was
wrong (or mis-informed and basing his conclusions on the behavior of MC17). MC18 already has the exact behavior he was looking for (or mostly, and certainly the relevant options). It defaults to his "middle choice" (which he said was acceptable), and provides options needed to enable both other choices.
To enable this "mode":
Manage my library - MC acts like iTunes in that it controls the library and it can do what it likes to any files
Options > General > Importing & Tagging > Update Tags When File Info Changes:
TrueOptions > Library & Folders > Configure Auto Import > Write file tags when analyzing audio, getting cover art, etc:
TrueOnly allow MC to make changes that I explicitly make - so tagging would be OK if I did it manually, but no automatic changes would be made
Default behavior.Options > General > Importing & Tagging > Update Tags When File Info Changes:
TrueOptions > Library & Folders > Configure Auto Import > Write file tags when analyzing audio, getting cover art, etc:
FalseMC is not allowed to make any changes to my files
Options > General > Importing & Tagging > Update Tags When File Info Changes:
FalseOptions > Library & Folders > Configure Auto Import > Write file tags when analyzing audio, getting cover art, etc:
Is IgnoredLastly...
One other small note I should mention: Using the Tag On Import rules in Auto-Import
counts as manually tagging files. With the default settings, this means if you define any Tag On Import rules, those changes will get written out to the files. That makes sense, though, as those are manually, explicitly defined.
The one thing I haven't tested is to see if only those Tag On Import changes get written to files, or if it flushes the current database state to the tags. I'd guess, based on the Automation interface behavior, that it is the latter (that if you write any tags via Tag On Import, that it "triggers" the Auto-Import specific option to be essentially ignored for "matching" files). Like I said, I'm not sure (and I don't really care, personally, as I enable both options and
want MC to fully manage my in-file tags -- it does a good job).
But, that caution would apply. If you don't want any "automated" tagging at all no matter what, you're
probably best avoiding the Tag On Import rules (or test it beforehand, at least). If you're that kind of person, though, you'd probably avoid using that feature anyway, so I think this is no big deal whatsoever.