Why does projectile-compile-project call “go build ./…”?

Question

I just started to use projectile. I use it with a go project. When I call projectile-compile-project, go build ./... runs, but after that there is no binary. The same happens when I call go build ./... from the shell.

• Why is go build ./... called and not go build?
• What does ./... mean anyway? I've never seen that in ~20 years of Linux command-line usage
• What's the preferred way to customize that globally (i.e. not in .dir-locals.el) for go-mode?

Answer 1

go build ./... will build the current directory and all subdirectories underneath it. ... is a wildcard indicator for the go tool documented here https://golang.org/cmd/go/:

An import path is a pattern if it includes one or more "..." wildcards, each of which can match any string, including the empty string and strings containing slashes. Such a pattern expands to all package directories found in the GOPATH trees with names matching the patterns.

To make common patterns more convenient, there are two special cases. First, /... at the end of the pattern can match an empty string, so that net/... matches both net and packages in its subdirectories, like net/http. Second, any slash-separated pattern element containing a wildcard never participates in a match of the "vendor" element in the path of a vendored package, so that ./... does not match packages in subdirectories of ./vendor or ./mycode/vendor, but ./vendor/... and ./mycode/vendor/... do. Note, however, that a directory named vendor that itself contains code is not a vendored package: cmd/vendor would be a command named vendor, and the pattern cmd/... matches it. See golang.org/s/go15vendor for more about vendoring.