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Project root directory

Usage​

Scala CLI needs a root directory:

  • to write mapped sources
  • to write class files
  • for Bloop

Setting root directory​

First of all, Scala CLI checks every passed input (in the same order in which inputs were passed) for the project.scala file:

  • If the project.scala file is passed explicitly as a source, Scala CLI sets its parent directory as the root directory.
  • If the input is a directory, Scala CLI looks for the project.scala inside this directory. If the file is found, Scala CLI sets the passed directory as the root directory.

If more than one project.scala file is found, Scala CLI uses only the first one to set the root directory and raises a warning saying which one was used.

If no project.scala files are found, Scala CLI sets the root directory based on the first file/directory input:

  • If the input is a directory, it is set as the root directory.
  • If the input is a file, Scala CLI sets its parent directory as the root directory.

If more than one file/directory input has been passed Scala CLI raises the warning saying which directory has been set as the project root directory.

If no project.scala files are found and no file/directory inputs have been passed, Scala CLI sets the current working directory (where Scala CLI was invoked from) as the project root directory.

Example​

Let's say we have the following file structure:

project
│   project.scala
│
└───dir1
│   │   file1.scala
│   │
│   └───dir2
│       │   project.scala
│       │   file2.scala
│   
└───dir3
    │   project.scala
    │   file3.scala

And the user runs the following command:

project> scala-cli dir1/file1.scala dir1/dir2 dir3/project.scala

Scala CLI will find 2 project.scala files:

  • inside dir2, since this directory was passed as an input and it has project.scala inside.
  • inside dir3, since dir3/project.scala was passed explicitly as a source

dir1/dir2 was passed before dir3/project.scala, so dir2 will be set as the root directory for this build.

Since more than one project.scala has been found, Scala CLI will raise the warning saying that more than one project.scala file has been found and dir1/dir2 has been set as the project root directory.