Don't expand ndots if prefixed with ./ (nushell#14755)

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# Description
Prevents ndots from being expanded if they are prefixed with `./`, as
the agreed resolution to nushell#13303. Only applies to externals, mirroring
the fix from nushell#13218.

I did
[attempt](https://github.com/132ikl/nushell/tree/internal-ndots-attempt)
to apply the fix for internal commands as well, but it seems like the
path is expanded too aggressively and I haven't investigated it further
yet. `./...` gets normalized into `<pwd>/./...`, which gets normalized
into `<pwd>/...` before being handed to `expand_ndots`, and at that
point it just looks like a normal n-dots so we can't tell we shouldn't
expand.

(Fixes nushell#13303)

# User-Facing Changes
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helps us keep track of breaking changes. -->

* N-dots are no longer expanded to external command calls when prefixed
with `./`.

# Tests + Formatting
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Added tests to prevent regression.

- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`

# After Submitting
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PR is merged, if necessary. This will help us keep the docs up to date.
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N/A

crates/nu-command/src/system/run_external.rs

@@ -1,6 +1,6 @@
 use nu_cmd_base::hook::eval_hook;
 use nu_engine::{command_prelude::*, env_to_strings};
-use nu_path::{dots::expand_ndots, expand_tilde, AbsolutePath};
+use nu_path::{dots::expand_ndots_safe, expand_tilde, AbsolutePath};
 use nu_protocol::{
     did_you_mean, process::ChildProcess, ByteStream, NuGlob, OutDest, Signals, UseAnsiColoring,
 };
@@ -639,21 +639,6 @@ fn escape_cmd_argument(arg: &Spanned<OsString>) -> Result<Cow<'_, OsStr>, ShellE
     }
 }
 
-/// Expand ndots, but only if it looks like it probably contains them, because there is some lossy
-/// path normalization that happens.
-fn expand_ndots_safe(path: impl AsRef<Path>) -> PathBuf {
-    let string = path.as_ref().to_string_lossy();
-
-    // Use ndots if it contains at least `...`, since that's the minimum trigger point, and don't
-    // use it if it contains ://, because that looks like a URL scheme and the path normalization
-    // will mess with that.
-    if string.contains("...") && !string.contains("://") {
-        expand_ndots(path)
-    } else {
-        path.as_ref().to_owned()
-    }
-}
-
 #[cfg(test)]
 mod test {
     use super::*;

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

@@ -247,6 +247,16 @@ fn external_command_ndots_args() {
     );
 }
 
+#[test]
+fn external_command_ndots_leading_dot_slash() {
+    // Don't expand ndots with a leading `./`
+    let actual = nu!(r#"
+        nu --testbin cococo ./... ./....
+    "#);
+
+    assert_eq!(actual.out, "./... ./....");
+}
+
 #[test]
 fn external_command_url_args() {
     // If ndots is not handled correctly, we can lose the double forward slashes that are needed

crates/nu-path/src/dots.rs

@@ -73,6 +73,23 @@ pub fn expand_dots(path: impl AsRef<Path>) -> PathBuf {
     simiplified(&result)
 }
 
+/// Expand ndots, but only if it looks like it probably contains them, because there is some lossy
+/// path normalization that happens.
+pub fn expand_ndots_safe(path: impl AsRef<Path>) -> PathBuf {
+    let string = path.as_ref().to_string_lossy();
+
+    // Use ndots if it contains at least `...`, since that's the minimum trigger point.
+    // Don't use it if it contains ://, because that looks like a URL scheme and the path normalization
+    // will mess with that.
+    // Don't use it if it starts with `./`, as to not break golang wildcard syntax
+    // (since generally you're probably not using `./` with ndots)
+    if string.contains("...") && !string.contains("://") && !string.starts_with("./") {
+        expand_ndots(path)
+    } else {
+        path.as_ref().to_owned()
+    }
+}
+
 #[cfg(windows)]
 fn simiplified(path: &std::path::Path) -> PathBuf {
     path.to_winuser_path()
@@ -169,6 +186,12 @@ mod test_expand_ndots {
         };
         assert_path_eq!(expand_ndots(path), expected);
     }
+
+    #[test]
+    fn leading_dot_slash() {
+        let path = Path::new("./...");
+        assert_path_eq!(expand_ndots_safe(path), "./...");
+    }
 }
 
 #[cfg(test)]

crates/nu-path/src/tilde.rs

@@ -152,7 +152,6 @@ fn expand_tilde_with_another_user_home(path: &Path) -> PathBuf {
 
 /// Expand tilde ("~") into a home directory if it is the first path component
 pub fn expand_tilde(path: impl AsRef<Path>) -> PathBuf {
-    // TODO: Extend this to work with "~user" style of home paths
     expand_tilde_with_home(path, dirs::home_dir())
 }