This is working as intended. gofmt has heuristics to drop indentation for consecutive tags of very different lengths. Closing as dup of #10392.

This is working as intended. gofmt has heuristics to drop indentation for consecutive tags of very different lengths.

FTR: OP's link https://play.golang.org/p/PXnPCVi6pz shows not a drop of indentation after formatting, its result looks like an off by one bug.

AFAICT that second link is being treated the same as the following for indentation (note the blank line in the middle):

var M = map[string]string{
	"quite long map key":     "bar",
	"very long map key aaaa": "baz",

	"shrt":                    "foo",
	"mid size key":            "aaa",
	"slightly longer key":     "bbb",
	"very long map key bbbbb": "ccc",
}

@benpaxton-hf See #10392 (comment) for an explanation.

I read through that one, yeah. I guess I just don't see the point of having that heuristic; if gofmt without that code produces highly-indented blocks, then the developer is using extremely long map keys; in that case, why not just suggest a blank line between the excessively-long keys and the short ones? What differs between the case of a struct with a very long variable or type name and the case of a map with a very long key that the heuristic is only used for one?

Edit: for clarity, I am @benpaxton-hf on my non-work account.

@GinjaNinja32 Your suggestion may be the right one. But we don't want to change this now as it would produce needless churn in many people's files. Perhaps a future gofmt 2.