fix: prevent empty separators (#108)

Author: rhysparry

src/env.rs

@@ -1,4 +1,5 @@
 use crate::json::JsonValueCommand;
+use crate::non_empty_separator;
 use crate::ValueReader;
 use clap::Args;
 use serde_json::{Map, Value};
@@ -18,7 +19,7 @@ pub struct EnvArgs {
     #[arg(long)]
     expand_path: bool,
     /// Separator to use when expanding the Path variable. Defaults to the platform-specific separator.
-    #[arg(long, requires = "expand_path")]
+    #[arg(long, requires = "expand_path", value_parser = non_empty_separator)]
     path_separator: Option<String>,
 }
 
@@ -103,6 +104,12 @@ mod tests {
     use crate::testing::TestBuffer;
     use serde_json::json;
 
+    #[derive(clap::Parser, Debug)]
+    struct EnvArgsParser {
+        #[command(flatten)]
+        args: EnvArgs,
+    }
+
     fn env_args_from_stdin() -> EnvArgs {
         let mut args = EnvArgs::default();
         args.from_stdin = true;
@@ -356,4 +363,11 @@ mod tests {
         args.expand_path_variable(&mut json_value);
         assert_eq!(json_value["PATH"], json!(["/usr/bin", "/bin"]));
     }
+
+    #[test]
+    fn empty_path_separator_is_rejected() {
+        use clap::Parser;
+        let result = EnvArgsParser::try_parse_from(["cmd", "--expand-path", "--path-separator="]);
+        assert!(result.is_err());
+    }
 }

src/lib.rs

@@ -8,6 +8,14 @@ pub mod objects;
 pub mod strings;
 pub mod testing;
 
+pub fn non_empty_separator(s: &str) -> Result<String, String> {
+    if s.is_empty() {
+        Err("separator must not be empty".to_string())
+    } else {
+        Ok(s.to_string())
+    }
+}
+
 pub fn read_all(input: &mut dyn BufRead) -> std::io::Result<String> {
     let mut buffer = String::new();
     for l in input.lines() {
@@ -53,4 +61,16 @@ mod tests {
         let result = read_all(&mut buffer).unwrap();
         assert_eq!(result, "Hello, world!\nThis is a test");
     }
+
+    #[test]
+    fn non_empty_separator_accepts_non_empty_string() {
+        assert_eq!(non_empty_separator("="), Ok("=".to_string()));
+        assert_eq!(non_empty_separator("=="), Ok("==".to_string()));
+        assert_eq!(non_empty_separator(":"), Ok(":".to_string()));
+    }
+
+    #[test]
+    fn non_empty_separator_rejects_empty_string() {
+        assert!(non_empty_separator("").is_err());
+    }
 }

src/objects.rs

@@ -1,4 +1,5 @@
 use crate::json::JsonValueCommand;
+use crate::non_empty_separator;
 use crate::ValueReader;
 use clap::Args;
 use serde_json::Map;
@@ -20,7 +21,7 @@ pub struct ObjectArgs {
     #[arg(long, group = "input")]
     empty: bool,
     /// Separator between key and value.
-    #[arg(long, short, default_value = "=")]
+    #[arg(long, short, default_value = "=", value_parser = non_empty_separator)]
     separator: String,
 }
 
@@ -98,6 +99,12 @@ mod tests {
     use crate::testing::TestBuffer;
     use serde_json::json;
 
+    #[derive(clap::Parser, Debug)]
+    struct ObjectArgsParser {
+        #[command(flatten)]
+        args: ObjectArgs,
+    }
+
     fn object_args(values: Vec<&str>) -> ObjectArgs {
         ObjectArgs {
             auto: false,
@@ -403,4 +410,11 @@ mod tests {
         let result = args.get_json_value();
         assert_eq!(result, json!({ "key": "value", "other": "thing" }));
     }
+
+    #[test]
+    fn test_object_args_empty_separator_is_rejected() {
+        use clap::Parser;
+        let result = ObjectArgsParser::try_parse_from(["cmd", "--separator=", "key=value"]);
+        assert!(result.is_err());
+    }
 }