Swift package manager. Error: Found multiple packages with the name...?

Question

Lets says:

B is a library which depends on CommonLib
App depends on B and CommonLib

Here are their mainfests

B's Package.swift:

import PackageDescription
let package = Package(
    name: "B",
    products: [
        .library(
            name: "B",
            targets: ["B"]),
    ],
    dependencies: [
      .package(url: "https://.../CommonLib", from: "1.0.0"),
   ],
    targets: [
        .target(
            name: "B",
            dependencies: ["CommonLib"]),
        .testTarget(
            name: "BTests",
            dependencies: ["B"]),
    ]
)

App's Package.swift

import PackageDescription
let package = Package(
    name: "App",
    dependencies: [
      .package(url: "https://.../CommonLib", from: "1.0.0"),
      .package(url: "https://.../B", from: "1.0.0"),
   ],
    targets: [
        .target(
            name: "App",
            dependencies: ["CommonLib", "B"]),
        .testTarget(
            name: "AppTests",
            dependencies: ["App"]),
    ]
)

swift build
error: Found multiple packages with the name CommonLib...

If both App and B depend on CommonLib and if I import B and CommonLib into App there is an error Found multiple packages with the name...

Apple Swift version 4.0.2 (swiftlang-900.0.69.2 clang-900.0.38) Target: x86_64-apple-macosx10.9

Does anyone know how to resolve this?

Answer 1

Remove Package.pins and rerun swift build. See which packages it is trying to fetch. Check .build/checkouts and .build/dependencies-state.json - which tags and which versions, respectively, of CommonLib, are written there.