Filesystem commands print --verbose to stderr (#8014)

# Description

Makes `mkdir`, `cp`, `mv` and `rm` return nothing and print info to
stderr:

![image](https://user-images.githubusercontent.com/17511668/217859228-feffa4bc-c22d-45d3-b330-1903f5a4d938.png)
See https://github.com/nushell/nushell/pull/7925#issuecomment-1420861638
and
[discord](https://discord.com/channels/601130461678272522/615329862395101194/1072523941865857055).

# User-Facing Changes

`mkdir`, `cp`, `mv` and `rm` will return nothing and print info to
stderr with `--verbose` flag.

# Tests + Formatting

Don't forget to add tests that cover your changes.

Make sure you've run and fixed any issues with these commands:

- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass

# After Submitting

If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.

crates/nu-command/src/filesystem/cp.rs

@@ -279,14 +279,19 @@ impl Command for Cp {
         }
 
         if verbose {
-            Ok(result.into_iter().into_pipeline_data(ctrlc))
+            result
+                .into_iter()
+                .into_pipeline_data(ctrlc)
+                .print_not_formatted(engine_state, false, true)?;
         } else {
             // filter to only errors
-            Ok(result
+            result
                 .into_iter()
                 .filter(|v| matches!(v, Value::Error { .. }))
-                .into_pipeline_data(ctrlc))
+                .into_pipeline_data(ctrlc)
+                .print_not_formatted(engine_state, false, true)?;
         }
+        Ok(PipelineData::empty())
     }
 
     fn examples(&self) -> Vec<Example> {

crates/nu-command/src/filesystem/mkdir.rs

@@ -19,7 +19,7 @@ impl Command for Mkdir {
 
     fn signature(&self) -> Signature {
         Signature::build("mkdir")
-            .input_output_types(vec![(Type::Nothing, Type::List(Box::new(Type::String)))])
+            .input_output_types(vec![(Type::Nothing, Type::Nothing)])
             .rest(
                 "rest",
                 SyntaxShape::Directory,
@@ -83,9 +83,11 @@ impl Command for Mkdir {
             }
         }
 
-        Ok(stream
+        stream
             .into_iter()
-            .into_pipeline_data(engine_state.ctrlc.clone()))
+            .into_pipeline_data(engine_state.ctrlc.clone())
+            .print_not_formatted(engine_state, false, true)?;
+        Ok(PipelineData::empty())
     }
 
     fn examples(&self) -> Vec<Example> {

crates/nu-command/src/filesystem/mv.rs

@@ -35,7 +35,7 @@ impl Command for Mv {
 
     fn signature(&self) -> nu_protocol::Signature {
         Signature::build("mv")
-            .input_output_types(vec![(Type::Nothing, Type::List(Box::new(Type::String)))])
+            .input_output_types(vec![(Type::Nothing, Type::Nothing)])
             .required(
                 "source",
                 SyntaxShape::GlobPattern,
@@ -177,7 +177,7 @@ impl Command for Mv {
         }
 
         let span = call.head;
-        Ok(sources
+        sources
             .into_iter()
             .flatten()
             .filter_map(move |entry| {
@@ -212,7 +212,9 @@ impl Command for Mv {
                     None
                 }
             })
-            .into_pipeline_data(ctrlc))
+            .into_pipeline_data(ctrlc)
+            .print_not_formatted(engine_state, false, true)?;
+        Ok(PipelineData::empty())
     }
 
     fn examples(&self) -> Vec<Example> {

crates/nu-command/src/filesystem/rm.rs

@@ -45,7 +45,7 @@ impl Command for Rm {
 
     fn signature(&self) -> Signature {
         let sig = Signature::build("rm")
-            .input_output_types(vec![(Type::Nothing, Type::List(Box::new(Type::String)))])
+            .input_output_types(vec![(Type::Nothing, Type::Nothing)])
             .required(
                 "filename",
                 SyntaxShape::Filepath,
@@ -329,7 +329,7 @@ fn rm(
         }
     }
 
-    Ok(all_targets
+    all_targets
         .into_keys()
         .map(move |f| {
             let is_empty = || match f.read_dir() {
@@ -450,5 +450,8 @@ fn rm(
             }
         })
         .filter(|x| !matches!(x.get_type(), Type::Nothing))
-        .into_pipeline_data(ctrlc))
+        .into_pipeline_data(ctrlc)
+        .print_not_formatted(engine_state, false, true)?;
+
+    Ok(PipelineData::empty())
 }

crates/nu-command/tests/commands/mkdir.rs

@@ -79,6 +79,8 @@ fn print_created_paths() {
             dirs.test()
         ));
 
-        assert_eq!(actual.out, "3");
+        assert!(actual.err.contains("dir_1"));
+        assert!(actual.err.contains("dir_2"));
+        assert!(actual.err.contains("dir_3"));
     })
 }

crates/nu-protocol/src/pipeline_data.rs

@@ -644,6 +644,33 @@ impl PipelineData {
         Ok(0)
     }
 
+    /// Consume and print self data immediately.
+    ///
+    /// Unlike [print] does not call `table` to format data and just prints it
+    /// one element on a line
+    /// * `no_newline` controls if we need to attach newline character to output.
+    /// * `to_stderr` controls if data is output to stderr, when the value is false, the data is output to stdout.
+    pub fn print_not_formatted(
+        self,
+        engine_state: &EngineState,
+        no_newline: bool,
+        to_stderr: bool,
+    ) -> Result<i64, ShellError> {
+        let config = engine_state.get_config();
+
+        if let PipelineData::ExternalStream {
+            stdout: stream,
+            stderr: stderr_stream,
+            exit_code,
+            ..
+        } = self
+        {
+            print_if_stream(stream, stderr_stream, to_stderr, exit_code)
+        } else {
+            self.write_all_and_flush(engine_state, config, no_newline, to_stderr)
+        }
+    }
+
     fn write_all_and_flush(
         self,
         engine_state: &EngineState,