fix: make time use timezone information

When a file timestamp is displayed, it should use the timezone info from
the time of the timestamp, not from when it is displayed. This occurs when
a file timestamp is updated under daylight saving time, and displayed at a
time when not under daylight saving time.

This bug is quite subtle, as it depends on the time of construction of the
timestamp, not on the moment it is read.

Cargo.toml

@@ -86,6 +86,8 @@ name = "eza"
 [dependencies]
 rayon = "1.10.0"
 chrono = { version = "0.4.34", default-features = false, features = ["clock"] }
+chrono-tz = "0.10.0"
+iana-time-zone = "0.1.58"
 nu-ansi-term = { version = "0.50.1", features = [
   "serde",
   "derive_serde_style",

src/output/render/times.rs

@@ -11,20 +11,33 @@ use chrono::prelude::*;
 use nu_ansi_term::Style;
 
 pub trait Render {
-    fn render(self, style: Style, time_offset: FixedOffset, time_format: TimeFormat) -> TextCell;
+    fn render(self, style: Style, time_format: TimeFormat) -> TextCell;
 }
 
 impl Render for Option<NaiveDateTime> {
-    fn render(self, style: Style, time_offset: FixedOffset, time_format: TimeFormat) -> TextCell {
-        let datestamp = if let Some(time) = self {
+    fn render(self, style: Style, time_format: TimeFormat) -> TextCell {
+        let datestamp = if let Ok(timezone_str) = iana_time_zone::get_timezone() {
+            let timezone: chrono_tz::Tz = timezone_str.parse().unwrap();
+            if let Some(time) = self {
+                let time_offset = timezone.offset_from_utc_datetime(&time).fix();
+                time_format.format(&DateTime::<FixedOffset>::from_naive_utc_and_offset(
+                    time,
+                    time_offset,
+                ))
+            } else {
+                String::from("-")
+            }
+        } else if let Some(time) = self {
+            // This is the next best thing, use the timezone now, instead of at the time of the
+            // timestamp.
+            let time_offset: FixedOffset = *Local::now().offset();
             time_format.format(&DateTime::<FixedOffset>::from_naive_utc_and_offset(
                 time,
                 time_offset,
             ))
         } else {
             String::from("-")
         };
-
         TextCell::paint(style, datestamp)
     }
 }

src/output/table.rs

@@ -363,9 +363,6 @@ impl Default for TimeTypes {
 ///
 /// Any environment field should be able to be mocked up for test runs.
 pub struct Environment {
-    /// The computer’s current time offset, determined from time zone.
-    time_offset: FixedOffset,
-
     /// Localisation rules for formatting numbers.
     numeric: locale::Numeric,
 
@@ -381,16 +378,13 @@ impl Environment {
     }
 
     fn load_all() -> Self {
-        let time_offset = *Local::now().offset();
-
         let numeric =
             locale::Numeric::load_user_locale().unwrap_or_else(|_| locale::Numeric::english());
 
         #[cfg(unix)]
         let users = Mutex::new(UsersCache::new());
 
         Self {
-            time_offset,
             numeric,
             #[cfg(unix)]
             users,
@@ -568,7 +562,6 @@ impl<'a> Table<'a> {
                 } else {
                     self.theme.ui.date.unwrap_or_default()
                 },
-                self.env.time_offset,
                 self.time_format.clone(),
             ),
         }

src/output/time.rs

@@ -196,4 +196,34 @@ mod test {
             .all(|string| UnicodeWidthStr::width(string.as_str()) == max_month_width)
         );
     }
+
+    #[test]
+    fn display_timestamp_correctly_in_timezone_with_dst() {
+        let timezone_str = "Europe/Berlin";
+        let timezone: chrono_tz::Tz = timezone_str.parse().unwrap();
+        let time = DateTime::<Utc>::from_timestamp(1685867700, 0)
+            .unwrap()
+            .naive_utc();
+
+        let fixed_offset = timezone.offset_from_utc_datetime(&time).fix();
+        let real_converted = DateTime::<FixedOffset>::from_naive_utc_and_offset(time, fixed_offset);
+        let formatted = full(&real_converted);
+        let expected = "2023-06-04 10:35:00.000000000 +0200";
+        assert_eq!(expected, formatted);
+    }
+
+    #[test]
+    fn display_timestamp_correctly_in_timezone_without_dst() {
+        let timezone_str = "Europe/Berlin";
+        let timezone: chrono_tz::Tz = timezone_str.parse().unwrap();
+        let time = DateTime::<Utc>::from_timestamp(1699090500, 0)
+            .unwrap()
+            .naive_utc();
+
+        let fixed_offset = timezone.offset_from_utc_datetime(&time).fix();
+        let real_converted = DateTime::<FixedOffset>::from_naive_utc_and_offset(time, fixed_offset);
+        let formatted = full(&real_converted);
+        let expected = "2023-11-04 10:35:00.000000000 +0100";
+        assert_eq!(expected, formatted);
+    }
 }