How to Fix Go build: “Cannot find package” (even though GOPATH is set)

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The “Cannot find package” error occurs in Go when you run the go build command even though your GOPATH is set, it’s possible that you’re not using Go modules, and your package import paths or directory structure may be incorrect.

Here are some steps to help you troubleshoot and fix the issue.

Step 1: Ensure your package is located in the correct directory

Make sure your package is located in the correct directory within your GOPATH. The package should be inside the src directory of your GOPATH. For example, if your GOPATH is set to /home/user/go, your package should be in /home/user/go/src/your-package-import-path. Replace your-package-import-path with the correct import path for your package.

Step 2: Verify that your import paths are correct

Make sure you’re using the correct import paths in your source code files and that they match the directory structure under your GOPATH. For example, if your package is at /home/user/go/src/github.com/yourusername/yourproject, you should use the import path github.com/yourusername/yourproject in your source code files.

Step 3: Switching to Go modules

If you are not using Go modules, consider switching to them. Go modules are recommended to manage dependencies and improve package discovery in Go projects. To switch to Go modules, first, make sure you’re using Go 1.11 or later, then follow these steps.

  1. Navigate to your project’s root directory.
  2. Run go mod init <module_name>, replacing <module_name> with your desired module name, typically your repository URL. For example: 
    go mod init github.com/yourusername/yourproject
  3. Run go build, go test, or other Go commands without worrying about the GOPATH. Go modules will handle your project’s dependencies automatically.

If you have checked your GOPATH, import paths, and directory structure, and you’re still encountering issues, please provide more specific information about your project’s layout and import paths so we can better assist you in the comment section.

That’s it.