Golang invalid import path when importing from "main" folder - go

Question

Been trying for the last few days to get rid of "invalid import path:"Atom First project/main/Extension" (build)" error when installing my main.go file but i haven't been able to find the reason behind the error.
OS - Windows 10
IDE - Atom
GOBIN - E:\Github Repository\Programming\Golang\bin
GOPATH - E:\Github Repository\Programming\Golang
File DIR- E:\Github Repository\Programming\Golang\src\Atom First project\main\main.go
E:\Github Repository\Programming\Golang\src\Atom First project\main\Extension/foo.go
main.go
package main
import (
"Atom First project/main/Extension"
)
func main() {
Extension.Extend()
}
foo.go
package Extension
import (
"fmt"
)
func Extend(){
fmt.Println("Hello from Extend func")
}

Answer 1

It's simple: import paths cannot contain spaces. Spec: Import declarations:
Implementation restriction: A compiler may restrict ImportPaths to non-empty strings using only characters belonging to Unicode's L, M, N, P, and S general categories (the Graphic characters without spaces) and may also exclude the characters !"#$%&'()*,:;<=>?[]^`{|} and the Unicode replacement character U+FFFD.
Simply rename your Atom First project folder to e.g. atom-first-project, and change the import declaration.
import (
"atom-first-project/main/Extension"
)
Also note that the package name (which is usually the folder name but not necessarily) must be a valid Go identifier. Spec: Package clause:
A package clause begins each source file and defines the package to which the file belongs.
PackageClause = "package" PackageName .
PackageName = identifier .