feat(time): time display use /etc/timezone

When a file timestamp is updated under daylight saving time, and
displayed when it is not, the wrong time offset is displayed (and vice
versa).

Fixes issue eza-community#653.

Cargo.toml

@@ -73,6 +73,8 @@ name = "eza"
 [dependencies]
 ansiterm = { version = "0.12.2", features = ["ansi_colours"] }
 chrono = { version = "0.4.31", default-features = false, features = ["clock"] }
+chrono-tz = "0.8.4"
+iana-time-zone = "0.1.58"
 glob = "0.3"
 libc = "0.2"
 locale = "0.2"

src/output/render/times.rs

@@ -5,12 +5,15 @@ use ansiterm::Style;
 use chrono::prelude::*;
 
 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 {
+    fn render(self, style: Style, time_format: TimeFormat) -> TextCell {
+        let timezone_str = iana_time_zone::get_timezone().unwrap();
+        let timezone: chrono_tz::Tz = timezone_str.parse().unwrap();
         let datestamp = 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,

src/output/table.rs

@@ -330,9 +330,6 @@ 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,
 
@@ -348,16 +345,13 @@ 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,
@@ -528,7 +522,6 @@ impl<'a> Table<'a> {
                 } else {
                     self.theme.ui.date
                 },
-                self.env.time_offset,
                 self.time_format.clone(),
             ),
         }

src/output/time.rs

@@ -175,4 +175,34 @@ 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);
+    }
 }