From 30f4cc1fef70391920ed2232c9125f5f0c81eecc Mon Sep 17 00:00:00 2001
From: Darren Schroeder <343840+fdncred@users.noreply.github.com>
Date: Tue, 13 Jun 2023 07:30:30 -0500
Subject: [PATCH] allow empty string arguments (#9420)

# Description

I'm not sure if this is a good idea or now but I did it to fix #9418. It
allows you to pass empty string arguments like this.

file named foo.nu
```
def main [--arg: string = dog] {
  if ($arg | is-empty) {
    echo "empty string"
  } else {
   echo $arg
  }
}
```
`> nu foo.nu --arg ""`
or
`> nu foo.nu --arg=""`
this gives an error
`> nu foo.nu --arg`
this returns the default argument
`> nu foo.nu`

closes #9418

# User-Facing Changes
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---
 crates/nu-parser/src/deparse.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/crates/nu-parser/src/deparse.rs b/crates/nu-parser/src/deparse.rs
index 98404490ad..e18da10ad8 100644
--- a/crates/nu-parser/src/deparse.rs
+++ b/crates/nu-parser/src/deparse.rs
@@ -26,6 +26,9 @@ pub fn escape_for_script_arg(input: &str) -> String {
                 format!("`{arg_val}`")
             } else if arg_val.contains('"') || arg_val.contains('\\') {
                 escape_quote_string(arg_val)
+            } else if arg_val.is_empty() {
+                // return an empty string
+                "''".to_string()
             } else {
                 arg_val.into()
             };
@@ -37,6 +40,9 @@ pub fn escape_for_script_arg(input: &str) -> String {
         format!("`{input}`")
     } else if input.contains('"') || input.contains('\\') {
         escape_quote_string(input)
+    } else if input.is_empty() {
+        // return an empty string
+        "''".to_string()
     } else {
         input.to_string()
     }