Fix fmt sub-command exit code to mirror that of the underlying scalafmt (#2463)

Author: Gedochao

modules/cli/src/main/scala/scala/cli/commands/fmt/Fmt.scala

@@ -115,12 +115,13 @@ object Fmt extends ScalaCommand[FmtOptions] {
         sourceFiles.map(_.toString) ++
         options.scalafmtCliOptions ++
         Seq("--config", scalaFmtConfPath.toString)
-      Runner.maybeExec(
+      val process = Runner.maybeExec(
         "scalafmt",
         command,
         logger,
         cwd = Some(workspace)
-      ).waitFor()
+      )
+      sys.exit(process.waitFor())
     }
   }
 }

modules/integration/src/test/scala/scala/cli/integration/FmtTests.scala

@@ -85,7 +85,9 @@ class FmtTests extends ScalaCliSuite {
 
   test("with --check") {
     simpleInputs.fromRoot { root =>
-      val out = os.proc(TestUtil.cli, "fmt", "--check").call(cwd = root, check = false).out.text()
+      val res = os.proc(TestUtil.cli, "fmt", "--check").call(cwd = root, check = false)
+      expect(res.exitCode == 1)
+      val out            = res.out.text()
       val updatedContent = noCrLf(os.read(root / "Foo.scala"))
       expect(updatedContent == noCrLf(simpleInputsUnformattedContent))
       expect(noCrLf(out) == "error: --test failed\n")

website/docs/commands/fmt.md

@@ -8,23 +8,23 @@ import {ChainedSnippets} from "../../src/components/MarkdownComponents.js";
 Scala CLI supports formatting your code using [Scalafmt](https://scalameta.org/scalafmt/):
 
 ```bash
-scala-cli fmt
+scala-cli fmt .
 ```
 
 Under the hood, Scala CLI downloads and runs Scalafmt on your code.
 
 If you’re setting up a continuous integration (CI) server, Scala CLI also has you covered.
 You can check formatting correctness using a `--check` flag:
 
-```bash
-scala-cli fmt --check
+```bash fail
+scala-cli fmt --check .
 ```
 
 ### Scalafmt version and dialect
 
 Scala CLI `fmt` command supports passing the `scalafmt` **version** and **dialect** directly from the command line, using the `--scalafmt-dialect` and `--scalafmt-version` options respectively:
 ```
-scala-cli fmt --scalafmt-dialect scala3 --scalafmt-version 3.5.8
+scala-cli fmt . --scalafmt-dialect scala3 --scalafmt-version 3.5.8
 ```
 You can skip passing either of those, which will make Scala CLI infer a default value:
 - If a `.scalafmt.conf` file is present in the workspace and it has the field defined, the value will be read from there, unless explicitly specified with Scala CLI options.
@@ -40,7 +40,7 @@ runner.dialect = scala212
 ```
 
 ```bash
-scala-cli fmt --scalafmt-dialect scala213
+scala-cli fmt --scalafmt-dialect scala213 .
 ```
 
 For the setup above, `fmt` will use:
@@ -54,7 +54,7 @@ version = "2.7.5"
 ```
 
 ```bash
-scala-cli fmt --scalafmt-version 3.5.8
+scala-cli fmt --scalafmt-version 3.5.8 .
 ```
 
 For the setup above, `fmt` will use: