Validate input range of du flags (#7962)

# Description
Fix #7953
Fix flags on `du` which should be positive and added some tests. 

# User-Facing Changes

_(List of all changes that impact the user experience here. This helps
us keep track of breaking changes.)_

# 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/platform/du.rs

@@ -27,9 +27,9 @@ pub struct DuArgs {
     deref: bool,
     exclude: Option<Spanned<String>>,
     #[serde(rename = "max-depth")]
-    max_depth: Option<i64>,
+    max_depth: Option<Spanned<i64>>,
     #[serde(rename = "min-size")]
-    min_size: Option<i64>,
+    min_size: Option<Spanned<i64>>,
 }
 
 impl Command for Du {
@@ -85,15 +85,25 @@ impl Command for Du {
         _input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
         let tag = call.head;
+        let min_size: Option<Spanned<i64>> = call.get_flag(engine_state, stack, "min-size")?;
+        let max_depth: Option<Spanned<i64>> = call.get_flag(engine_state, stack, "max-depth")?;
+        if let Some(ref max_depth) = max_depth {
+            if max_depth.item < 0 {
+                return Err(ShellError::NeedsPositiveValue(max_depth.span));
+            }
+        }
+        if let Some(ref min_size) = min_size {
+            if min_size.item < 0 {
+                return Err(ShellError::NeedsPositiveValue(min_size.span));
+            }
+        }
         let args = DuArgs {
             path: call.opt(engine_state, stack, 0)?,
             all: call.has_flag("all"),
             deref: call.has_flag("deref"),
             exclude: call.get_flag(engine_state, stack, "exclude")?,
-            max_depth: call
+            max_depth,
-                .get_flag::<i64>(engine_state, stack, "max-depth")?
+            min_size,
-                .map(|n| (n as u64).try_into().expect("error converting i64 to u64")),
-            min_size: call.get_flag(engine_state, stack, "min-size")?,
         };
 
         let exclude = args.exclude.map_or(Ok(None), move |x| {
@@ -145,8 +155,8 @@ impl Command for Du {
 
         let all = args.all;
         let deref = args.deref;
-        let max_depth = args.max_depth.map(|f| f as u64);
+        let max_depth = args.max_depth.map(|f| f.item as u64);
-        let min_size = args.min_size.map(|f| f as u64);
+        let min_size = args.min_size.map(|f| f.item as u64);
 
         let params = DirBuilder {
             tag,

crates/nu-command/tests/commands/platform/du.rs

@@ -0,0 +1,43 @@
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn test_du_flag_min_size() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            du -m -1
+        "#
+    ));
+    assert!(actual
+        .err
+        .contains("Negative value passed when positive one is required"));
+
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            du -m 1
+        "#
+    ));
+    assert!(actual.err.is_empty());
+}
+
+#[test]
+fn test_du_flag_max_depth() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            du -d -2
+        "#
+    ));
+    assert!(actual
+        .err
+        .contains("Negative value passed when positive one is required"));
+
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            du -d 2
+        "#
+    ));
+    assert!(actual.err.is_empty());
+}

crates/nu-command/tests/commands/platform/mod.rs

@@ -1 +1,2 @@
+mod du;
 mod kill;