The getter.FileDetector was intended to be the final detector, only
converting a path to a file URL and returning a true in all cases. We
want to check for a local module before checking the registry so no
local modules that happen to match a registry module are broken.
Wrap the getter.FileDetector to check the module source's existence
before delegating the search to the registry.
Add a getter.Detector for detecting registry modules and looking up
the download location of the latest version. This is essentially a
temporary API until constraint solving is supported by the registry, as
then we'll have to supply the full set of known contraints to the
registry at once for resolution and we will fetch specific versions of
modules.
When copying a config module, make sure the full path for src and dst
files don't match, and also check the inode in case we resolved a
different path to the same file.
Make a note about the unsafe usage of reusing a tempDir path.
Using url.Parse to parse an absolute file path on Windows yields
a URL type where the Path element is prefixed by a slash.
For example, parsing "file:///C:/Users/user" gives a URL type
with Path:"/C:/Users/user".
According to golang.org/issue/6027, the parsing is correct as is.
The leading slash on the Path must be eliminated before any file
operations.
This commit introduces a urlParse function which wraps the url.Parse
functionality and removes the leading slash in Path for absolute file
paths on Windows.
Fixes config/module test failures on Windows.