fix(time-style): cryptic panic with invalid --time-syle format string

Validate --time-style format string during option parsing so we can give
a good error message rather than let rayon handle the panic and give no
context.

Fixes: #1240

src/options/view.rs

@@ -18,6 +18,8 @@ use crate::output::table::{
 use crate::output::time::TimeFormat;
 use crate::output::{details, grid, Mode, TerminalWidth, View};
 
+use chrono::format::{Item, StrftimeItems};
+
 impl View {
     pub fn deduce<V: Vars>(matches: &MatchedFlags<'_>, vars: &V) -> Result<Self, OptionsError> {
         let mode = Mode::deduce(matches, vars)?;
@@ -350,12 +352,17 @@ impl TimeFormat {
                 //   - there is nothing after `+`
                 // line 1 will be empty when:
                 //   - `+` is followed immediately by `\n`
-                let empty_non_recent_format_msg = "Custom timestamp format is empty, \
-                    please supply a chrono format string after the plus sign.";
-                let non_recent = lines.next().expect(empty_non_recent_format_msg);
+                let invalid_non_recent_format_msg = "Custom timestamp format is invalid, \
+                    please supply a valid chrono format string after the plus sign.";
+                let non_recent = lines.next().expect(invalid_non_recent_format_msg);
                 let non_recent = if non_recent.is_empty() {
-                    panic!("{}", empty_non_recent_format_msg)
+                    panic!("{}", invalid_non_recent_format_msg)
                 } else {
+                    StrftimeItems::new(non_recent).for_each(|item| {
+                        if matches!(item, Item::Error) {
+                            panic!("{}", invalid_non_recent_format_msg)
+                        }
+                    });
                     non_recent.to_owned()
                 };
 
@@ -364,12 +371,18 @@ impl TimeFormat {
                 //   - there is nothing after the first `\n`
                 // line 2 will be empty when:
                 //   - there exist at least 2 `\n`, and no content between the 1st and 2nd `\n`
-                let empty_recent_format_msg = "Custom timestamp format for recent files is empty, \
-                    please supply a chrono format string at the second line.";
+                let invalid_recent_format_msg =
+                    "Custom timestamp format for recent files is invalid, \
+                    please supply a valid chrono format string at the second line.";
                 let recent = lines.next().map(|rec| {
                     if rec.is_empty() {
-                        panic!("{}", empty_recent_format_msg)
+                        panic!("{}", invalid_recent_format_msg)
                     } else {
+                        StrftimeItems::new(rec).for_each(|item| {
+                            if matches!(item, Item::Error) {
+                                panic!("{}", invalid_recent_format_msg)
+                            }
+                        });
                         rec.to_owned()
                     }
                 });