fix: number-of-lines option in config file is ignored (#528)

Co-authored-by: andy.boot <bootandy@gmail.com>

src/config.rs

@@ -36,6 +36,7 @@ pub struct Config {
     pub output_json: Option<bool>,
     pub print_errors: Option<bool>,
     pub files0_from: Option<String>,
+    pub number_of_lines: Option<usize>,
     pub files_from: Option<String>,
 }
 
@@ -156,6 +157,15 @@ impl Config {
         Some(true) == self.output_json || options.output_json
     }
 
+    pub fn get_number_of_lines(&self, options: &Cli) -> Option<usize> {
+        let from_cmd_line = options.number_of_lines;
+        if from_cmd_line.is_none() {
+            self.number_of_lines
+        } else {
+            from_cmd_line
+        }
+    }
+
     pub fn get_modified_time_operator(&self, options: &Cli) -> Option<(Operator, i64)> {
         get_filter_time_operator(options.mtime.as_ref(), get_current_date_epoch_seconds())
     }
@@ -389,4 +399,33 @@ mod tests {
     fn get_filetime_args(args: Vec<&str>) -> Cli {
         Cli::parse_from(args)
     }
+
+    #[test]
+    fn test_get_number_of_lines() {
+        // No config and no flag.
+        let c = Config::default();
+        let args = get_args(vec![]);
+        assert_eq!(c.get_number_of_lines(&args), None);
+
+        // Config is not defined and flag is defined.
+        let c = Config::default();
+        let args = get_args(vec!["dust", "--number-of-lines", "5"]);
+        assert_eq!(c.get_number_of_lines(&args), Some(5));
+
+        // Config is defined and flag is not defined.
+        let c = Config {
+            number_of_lines: Some(3),
+            ..Default::default()
+        };
+        let args = get_args(vec![]);
+        assert_eq!(c.get_number_of_lines(&args), Some(3));
+
+        // Both config and flag are defined.
+        let c = Config {
+            number_of_lines: Some(3),
+            ..Default::default()
+        };
+        let args = get_args(vec!["dust", "--number-of-lines", "5"]);
+        assert_eq!(c.get_number_of_lines(&args), Some(5));
+    }
 }

src/main.rs

@@ -154,7 +154,7 @@ fn main() {
     // If depth is set, then we set the default number_of_lines to be max
     // instead of screen height
 
-    let number_of_lines = match options.number_of_lines {
+    let number_of_lines = match config.get_number_of_lines(&options) {
         Some(val) => val,
         None => {
             if depth != usize::MAX {