From 5fec0d785a2a89debc1dca3e4bd8161f72ad18f5 Mon Sep 17 00:00:00 2001
From: zakuro <z@kuro.red>
Date: Sat, 12 Dec 2020 17:19:03 +0900
Subject: [PATCH] time: fix timezone problems of parse_iso8601  (#7272)

---
 .github/workflows/ci.yml |  8 ++++
 vlib/time/parse.v        |  5 +--
 vlib/time/parse_test.v   | 92 ++++++++++++++++++++--------------------
 3 files changed, 55 insertions(+), 50 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 81c43d12b2..9051663184 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -95,6 +95,14 @@ jobs:
       run: ./v -o v2 cmd/v && ./v2 -o v3 cmd/v && ./v3 -o v4 cmd/v
     - name: Fixed tests
       run: ./v -silent test-fixed
+    - name: Test time functions in a timezone UTC-12
+      run: TZ=Etc/GMT+12 ./v test vlib/time/
+    - name: Test time functions in a timezone UTC-3
+      run: TZ=Etc/GMT+3 ./v test vlib/time/
+    - name: Test time functions in a timezone UTC+3
+      run: TZ=Etc/GMT-3 ./v test vlib/time/
+    - name: Test time functions in a timezone UTC+12
+      run: TZ=Etc/GMT-12 ./v test vlib/time/
     - name: Test building v tools
       run: ./v -silent build-tools
     - name: v doctor
diff --git a/vlib/time/parse.v b/vlib/time/parse.v
index 059b5b4419..ad484994d6 100644
--- a/vlib/time/parse.v
+++ b/vlib/time/parse.v
@@ -91,11 +91,8 @@ pub fn parse_iso8601(s string) ?Time {
 		second: second
 		microsecond: mic_second
 	})
-	if is_utc {
-		return t
-	}
 	if is_local_time {
-		return to_local_time(t)
+		return t // Time already local time
 	}
 	mut unix_time := t.unix
 	mut unix_offset := int(0)
diff --git a/vlib/time/parse_test.v b/vlib/time/parse_test.v
index decafea825..f28c3ea1d1 100644
--- a/vlib/time/parse_test.v
+++ b/vlib/time/parse_test.v
@@ -1,4 +1,5 @@
 import time
+import math
 
 fn test_parse() {
 	s := '2018-01-27 12:48:34'
@@ -48,61 +49,60 @@ fn test_parse_rfc2822_invalid() {
 	assert false
 }
 
-fn test_iso8601_parse_utc() {
+fn test_parse_iso8601() {
+	// Because there is a small difference between time.now() - time.utc and actual offset,
+	// round to the nearest hour.
+	offset := time.Duration(i64(math.round((time.now() - time.utc()).hours())) * time.hour)
 	formats := [
-		'2020-06-05T15:38:06.015959Z',
 		'2020-06-05T15:38:06Z',
+		'2020-06-05T15:38:06.015959Z',
+		'2020-06-05T15:38:06.015959+00:00',
+		'2020-06-05T15:38:06.015959+02:00',
+		'2020-06-05T15:38:06.015959-02:00',
 	]
 	times := [
-		[2020, 6, 5, 15, 38, 6, 15959],
 		[2020, 6, 5, 15, 38, 6, 0],
+		[2020, 6, 5, 15, 38, 6, 15959],
+		[2020, 6, 5, 15, 38, 6, 15959],
+		[2020, 6, 5, 13, 38, 6, 15959],
+		[2020, 6, 5, 17, 38, 6, 15959],
 	]
 	for i, format in formats {
-		t := time.parse_iso8601(format) or { panic(err) }
-		tt := times[i]
-		assert t.year == tt[0]
-		assert t.month == tt[1]
-		assert t.day == tt[2]
-		assert t.hour == tt[3]
-		assert t.minute == tt[4]
-		assert t.second == tt[5]
-		assert t.microsecond == tt[6]
+		t := time.parse_iso8601(format) or {
+			assert false
+			continue
+		}
+		data := times[i]
+		t2 := time.new_time(
+			year: data[0]
+			month: data[1]
+			day: data[2]
+			hour: data[3]
+			minute: data[4]
+			second: data[5]
+			microsecond: data[6]
+		).add(offset)
+		assert t.year == t2.year
+		assert t.month == t2.month
+		assert t.day == t2.day
+		assert t.hour == t2.hour
+		assert t.minute == t2.minute
+		assert t.second == t2.second
+		assert t.microsecond == t2.microsecond
 	}
 }
 
-fn test_iso8601_parse_local() {
-	format_utc := '2020-06-05T15:38:06.015959'
-	t_utc := time.parse_iso8601(format_utc) or {
-		panic(err)
+fn test_parse_iso8601_local() {
+	format := '2020-06-05T15:38:06.015959'
+	t := time.parse_iso8601(format) or {
+		assert false
+		return
 	}
-	assert t_utc.year == 2020
-	assert t_utc.month == 6
-	assert t_utc.day == 5
-}
-
-fn test_iso8601_parse_utc_diff() {
-	format_utc := '2020-06-05T15:38:06.015959+00:00'
-	format_cest := '2020-06-05T15:38:06.015959+02:00'
-	t_utc := time.parse_iso8601(format_utc) or {
-		panic(err)
-	}
-	t_cest := time.parse_iso8601(format_cest) or {
-		panic(err)
-	}
-	assert t_utc.year == 2020
-	assert t_cest.year == 2020
-	assert t_utc.month == 6
-	assert t_cest.month == 6
-	assert t_utc.day == 5
-	assert t_cest.day == 5
-	// if it was formatted in utc it should be
-	// two hours before if it was formatted in
-	// cest time
-	assert t_utc.hour == (t_cest.hour + 2)
-	assert t_utc.minute == 38
-	assert t_cest.minute == 38
-	assert t_utc.second == 6
-	assert t_cest.second == 6
-	assert t_utc.microsecond == 15959
-	assert t_cest.microsecond == 15959
+	assert t.year == 2020
+	assert t.month == 6
+	assert t.day == 5
+	assert t.hour == 15
+	assert t.minute == 38
+	assert t.second == 6
+	assert t.microsecond == 15959
 }