sbt can't find local repository defined by Resolver.file() - scala

Question

I use
name := "sbt-publish-test"
version := "0.1-SNAPSHOT"
publishTo := Some(Resolver.file("sbt-repo", file("/home/pishen/sbt-repo")))
and sbt publish to publish my project into the directory.
Now in another project, I want to resolve the project I just published. I use
resolvers += "my-repo" at "file:///home/pishen/sbt-repo"
libraryDependencies += "default" %% "sbt-publish-test" % "0.1-SNAPSHOT"
and is able to resolve the project without any error. The result of show resolvers is:
> show resolvers
[info] List(my-repo: file:///home/pishen/sbt-repo)
But, when I use
resolvers += Resolver.file("my-repo", file("/home/pishen/sbt-repo"))
libraryDependencies += "default" %% "sbt-publish-test" % "0.1-SNAPSHOT"
The result of show resolvers become:
> show resolvers
[info] List(FileRepository(my-repo,FileConfiguration(true,None),Patterns(ivyPatterns=List(), artifactPatterns=List(/home/pishen/sbt-repo/[organisation]/[module](_[scalaVersion])(_[sbtVersion])/[revision]/[artifact]-[revision](-[classifier]).[ext]), isMavenCompatible=true, descriptorOptional=false, skipConsistencyCheck=false)))
and sbt said that it can't resolve the dependency when I typed sbt update:
[warn] module not found: default#sbt-publish-test_2.10;0.1-SNAPSHOT
[warn] ==== local: tried
[warn] /home/pishen/.ivy2/local/default/sbt-publish-test_2.10/0.1-SNAPSHOT/ivys/ivy.xml
[warn] ==== public: tried
[warn] https://repo1.maven.org/maven2/default/sbt-publish-test_2.10/0.1-SNAPSHOT/sbt-publish-test_2.10-0.1-SNAPSHOT.pom
[warn] ==== my-repo: tried
[info] Resolving org.fusesource.jansi#jansi;1.4 ...
[warn] ::::::::::::::::::::::::::::::::::::::::::::::
[warn] :: UNRESOLVED DEPENDENCIES ::
[warn] ::::::::::::::::::::::::::::::::::::::::::::::
[warn] :: default#sbt-publish-test_2.10;0.1-SNAPSHOT: not found
[warn] ::::::::::::::::::::::::::::::::::::::::::::::
Is this a bug? Or am I use Resolver.file() in a wrong way? What's the difference between "name" at "url" and Resolver.file()? I'm using sbt 0.13.7.

Answer 1

My suspicion is that when you use Resolver.file in that context, it's intended to be more of a "builder" creator, expecting subsequent method calls to fill in additional configuration information that have different defaults when using the "name" at "uri" syntax.
The sbt ScalaDoc for Resolver.file.apply alludes to something along these lines:
Constructs a file resolver with the given name. The patterns to use must be explicitly specified using the ivys or artifacts methods on the constructed resolver object.
When I've done something similar to what you're doing, I start with a File and use its API to convert it into the URI form:
resolvers += "my-repo" at file("/home/pishen/sbt-repo").toURI.toASCIIString