Apply Africa/Casablanca rearguard fix (#6112)

components/timezone/src/types.rs

@@ -372,11 +372,11 @@ impl FromStr for UtcOffset {
 /// * `Europe/Dublin` (since 1968-10-27) sets the `isdst` flag during winter (UTC+0),
 ///   and does not set it during daylight saving time in summer (UTC+1). This leads
 ///   to incorrect display names in variant-sensitive formats:
-///     * ⚠️ "Greenwhich Mean Time" in summer (UTC+1)
+///     * ⚠️ "Greenwich Mean Time" in summer (UTC+1)
 ///     * ⚠️ "Ireland Standard Time" (the summer time name) in winter (UTC+0)
 ///
 ///   This is especially problematic as Northern Ireland (`Europe/Belfast`) sets the `isdst`
-///   flag during DST (UTC+1), so it correctly uses "Greenwhich Mean Time" in the winter (and
+///   flag during DST (UTC+1), so it correctly uses "Greenwich Mean Time" in the winter (and
 ///   "British Summer Time" in the summer).
 /// * `Africa/Winkhoek` between 1994-03-20 and 2017-10-24 sets the `isdst`
 ///   flag during winter (UTC+1), and does not set it during daylight saving
@@ -388,8 +388,8 @@ impl FromStr for UtcOffset {
 ///   sets the `isdst` flag during Ramadan (UTC+0), and does not set it
 ///   during daylight saving time (rest of the year, UTC+1). This leads
 ///   to incorrect display names in variant-sensitive formats:
-///   * ⚠️ "Western European Summer Time" during Ramadan (UTC+0)
-///   * ⚠️ "Western European Standard Time" the rest of the year (UTC+1)
+///   * ⚠️ "Morocco Daylight Time" during Ramadan (UTC+0)
+///   * ⚠️ "Morocco Standard Time" the rest of the year (UTC+1)
 #[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
 #[zerovec::make_ule(ZoneVariantULE)]
 #[repr(u8)]

provider/data/timezone/fingerprints.csv

@@ -1,4 +1,4 @@
 bcp47/to/iana/map/v1, <singleton>, 7622B, 7600B, 35e1d2b320b41234
 iana/to/bcp47/map/v3, <singleton>, 9543B, 9500B, 7218ae639c063764
 windows/zones/to/bcp47/map/v1, <singleton>, 8634B, 8591B, 90b7fe3f9cadf5bd
-zone/offset/period/v1, <singleton>, 13410B, 13322B, 365de2348b6c56dc
+zone/offset/period/v1, <singleton>, 13410B, 13322B, dda8d1981591b7cc

provider/source/src/source.rs

@@ -512,6 +512,31 @@ impl TzdbCache {
                     }
                 }
 
+                // Morocco doesn't have have rearguard data in the text file, so we have to replicate the transform from
+                // ziguard.awk: https://github.com/eggert/tz/blob/271a5784a59e454b659d85948b5e65c17c11516a/ziguard.awk#L261-L299
+                for line in lines.iter_mut() {
+                    if line.starts_with("Rule\tMorocco") {
+                        let mut parts = line.split('\t').skip(2);
+                        let from = parts.next().unwrap();
+                        let to = parts.next().unwrap();
+                        let _type = parts.next().unwrap();
+                        let month = parts.next().unwrap();
+                        let _day = parts.next().unwrap();
+                        let _time = parts.next().unwrap();
+                        let save = parts.next().unwrap();
+                        if to == "2018" && month == "Oct" {
+                            *line = line.replace("2018", "2017");
+                        } else if from.parse::<i32>().unwrap() >= 2019 {
+                            if save.trim() == "0" {
+                                *line = line.replace("\t0\t", "\t1:00\t");
+                            } else {
+                                *line = line.replace("\t-1:00\t", "\t0\t");
+                            }
+                        }
+                    }
+                    *line = line.replace("1:00\tMorocco\t%z", "0:00\tMorocco\t+00/+01");
+                }
+
                 #[allow(deprecated)] // no alternative?!
                 let parser = LineParser::new();
                 let mut table = TableBuilder::new();