Using SPM results in a "dependency graph is unresolvable" error.

[sbromberger]

• I've read, understood, and done my best to follow the *CONTRIBUTING guidelines.

What did you do?

Following #2950, I added

dependencies: [
   .package(url: "https://github.com/danielgindi/Charts.git", from: "3.1.1")
]

to a brand-new Package.swift created by swift package init, and attempted to download the dependency and build the project using swift build.

What did you expect to happen?

I expected swift build to succeed.

What happened instead?

I received the following output:

Updating https://github.com/danielgindi/Charts.git
error: dependency graph is unresolvable; found these conflicting requirements:

Dependencies: 
    https://github.com/danielgindi/Charts.git @ 3.1.1..<4.0.0

Charts Environment

Charts version/Branch/Commit Number:
n/a (trying to use 3.1.1)

Xcode version:
9.3 (9E145)
Swift version:
4.1.1
Platform(s) running Charts:
MacBook Pro (13-inch, 2016, Four Thunderbolt 3 Ports)
macOS version running Xcode:
MacOS High Sierra (10.13.4)

Demo Project

Here's the full Package.swift:

// swift-tools-version:4.0
// The swift-tools-version declares the minimum version of Swift required to build this package.

import PackageDescription

let package = Package(
    name: "ChartTest",
    products: [
        .library(
            name: "ChartTest",
            targets: ["ChartTest"]),
    ],
    dependencies: [
        .package(url: "https://github.com/danielgindi/Charts.git", from: "3.1.1")
    ],
    targets: [
        .target(
            name: "ChartTest",
            dependencies: ["Charts"]),
        .testTarget(
            name: "ChartTestTests",
            dependencies: ["ChartTest"]),
    ]
)

[liuxuan30]

any swift pkg expert could help? Not sure it's about our issue.

[pmairoldi]

The v in our tags is the problem. I just pushed a rename of the latest release as 3.1.1 instead of v3.1.1. Seems to work now.