Workaround for Windows local time prior to 1601

src/datetime/tests.rs

@@ -1265,6 +1265,17 @@ fn test_datetime_from_timestamp_millis() {
     );
 }
 
+#[test]
+#[cfg(feature = "clock")]
+fn test_datetime_before_windows_api_limits() {
+    // dt corresponds to `FILETIME = 147221225472` from issue 651.
+    // This used to fail on Windows for timezones with an offset of -5:00 or greater.
+    // The API limits years to 1601..=30827.
+    let dt = NaiveDate::from_ymd_opt(1601, 1, 1).unwrap().and_hms_milli_opt(4, 5, 22, 122).unwrap();
+    let local_dt = Local.from_utc_datetime(&dt);
+    dbg!(local_dt);
+}
+
 #[test]
 #[cfg(feature = "clock")]
 fn test_years_elapsed() {

src/offset/local/win_bindings.rs

@@ -5,6 +5,7 @@
 ::windows_targets::link!("kernel32.dll" "system" fn SystemTimeToTzSpecificLocalTime(lptimezoneinformation : *const TIME_ZONE_INFORMATION, lpuniversaltime : *const SYSTEMTIME, lplocaltime : *mut SYSTEMTIME) -> BOOL);
 ::windows_targets::link!("kernel32.dll" "system" fn TzSpecificLocalTimeToSystemTime(lptimezoneinformation : *const TIME_ZONE_INFORMATION, lplocaltime : *const SYSTEMTIME, lpuniversaltime : *mut SYSTEMTIME) -> BOOL);
 pub type BOOL = i32;
+pub const ERROR_INVALID_PARAMETER: WIN32_ERROR = 87u32;
 #[repr(C)]
 pub struct FILETIME {
     pub dwLowDateTime: u32,
@@ -49,3 +50,4 @@ impl ::core::clone::Clone for TIME_ZONE_INFORMATION {
         *self
     }
 }
+pub type WIN32_ERROR = u32;

src/offset/local/win_bindings.txt

@@ -1,6 +1,7 @@
 --out src/offset/local/win_bindings.rs
 --config flatten sys
 --filter
+    Windows.Win32.Foundation.ERROR_INVALID_PARAMETER
     Windows.Win32.System.Time.SystemTimeToFileTime
     Windows.Win32.System.Time.SystemTimeToTzSpecificLocalTime
     Windows.Win32.System.Time.TzSpecificLocalTimeToSystemTime

src/offset/local/windows.rs

@@ -15,7 +15,7 @@ use std::result::Result;
 
 use super::win_bindings::{
     SystemTimeToFileTime, SystemTimeToTzSpecificLocalTime, TzSpecificLocalTimeToSystemTime,
-    FILETIME, SYSTEMTIME,
+    ERROR_INVALID_PARAMETER, FILETIME, SYSTEMTIME,
 };
 
 use super::FixedOffset;
@@ -61,8 +61,28 @@ pub(super) fn offset(d: &NaiveDateTime, local: bool) -> LocalResult<FixedOffset>
     LocalResult::None
 }
 
-fn from_utc_time(utc_time: SYSTEMTIME) -> Result<FixedOffset, Error> {
-    let local_time = utc_to_local_time(&utc_time)?;
+fn from_utc_time(mut utc_time: SYSTEMTIME) -> Result<FixedOffset, Error> {
+    let local_time = match utc_to_local_time(&utc_time) {
+        Ok(time) => time,
+        // Workaround for #1364
+        // If converting to local time fails with `ERROR_INVALID_PARAMETER`
+        // and the date is 1601-01-01 then try again with the year set to 1602.
+        // This is usually a bad idea as offsets can be different depending on the year.
+        // However, 1601 is long enough ago that dynamic timezones aren't an issue
+        // and timezone offsets are much less than a year.
+        Err(e) => {
+            if e.raw_os_error() == Some(ERROR_INVALID_PARAMETER as i32)
+                && utc_time.wYear == 1601
+                && utc_time.wMonth == 1
+                && utc_time.wDay == 1
+            {
+                utc_time.wYear = 1602;
+                return from_utc_time(utc_time);
+            } else {
+                return Err(e);
+            }
+        }
+    };
     let utc_secs = system_time_as_unix_seconds(&utc_time)?;
     let local_secs = system_time_as_unix_seconds(&local_time)?;
     let offset = (local_secs - utc_secs) as i32;