fix(date): use available timezone if any (#94)

## Description

It's important to use the date timezone if it has any.

## Changes

Do not switch back to Local timezone if not needed

## Fixes #81 

## Checklist
- [X] I have read the **CONTRIBUTING.md** document.
- [X] My code follows the code style of this project.
- [X] I have added tests to cover my changes.
- [X] All new and existing tests passed.
- [ ] I have updated the documentation accordingly.
- [ ] This change requires a change to the documentation on the website.

## Additional Information
<!-- Any additional information regarding this pull request. -->

Timezones are always fun

---------

Signed-off-by: ccoVeille <[email protected]>
Co-authored-by: Atomys <[email protected]>

Author: ccoVeille

.golangci.yaml

@@ -1,5 +1,5 @@
 ---
-# Thanks to @ccoVeille for the configuration template from 
+# Thanks to @ccoVeille for the configuration template from
 # https://github.com/ccoVeille/golangci-lint-config-examples
 linters:
   enable:
@@ -9,6 +9,7 @@ linters:
     - gofumpt
     - gosimple
     - govet
+    - importas
     - ineffassign
     - staticcheck
     - misspell
@@ -19,6 +20,12 @@ linters:
     - usestdlibvars
 
 linters-settings:
+  importas:
+    alias:
+      # prevent conflicts with first level std packages
+      - pkg:  "[a-z][0-9a-z]+"
+        alias: ""
+
   gofumpt:
     module-path: github.com/go-sprout/sprout
   misspell:

benchmarks/comparison_test.go

@@ -9,7 +9,7 @@ import (
 	"sync"
 	"testing"
 	"text/template"
-	gotime "time"
+	"time"
 
 	"github.com/Masterminds/sprig/v3"
 	"github.com/go-sprout/sprout"
@@ -29,7 +29,7 @@ import (
 	"github.com/go-sprout/sprout/registry/slices"
 	"github.com/go-sprout/sprout/registry/std"
 	"github.com/go-sprout/sprout/registry/strings"
-	"github.com/go-sprout/sprout/registry/time"
+	rtime "github.com/go-sprout/sprout/registry/time"
 	"github.com/go-sprout/sprout/registry/uniqueid"
 	"github.com/go-sprout/sprout/sprigin"
 	"github.com/stretchr/testify/assert"
@@ -48,8 +48,8 @@ var data = map[string]any{
 	"object":      struct{ Name string }{"example object"},
 	"func":        func() string { return "example function" },
 	"error":       fmt.Errorf("example error"),
-	"time":        gotime.Now(),
-	"duration":    5 * gotime.Second,
+	"time":        time.Now(),
+	"duration":    5 * time.Second,
 	"channel":     make(chan any),
 	"json":        `{"foo": "bar"}`,
 	"yaml":        "foo: bar",
@@ -136,7 +136,7 @@ func sproutBench(templatePath string) {
 		semver.NewRegistry(),
 		backward.NewRegistry(),
 		reflect.NewRegistry(),
-		time.NewRegistry(),
+		rtime.NewRegistry(),
 		strings.NewRegistry(),
 		random.NewRegistry(),
 		checksum.NewRegistry(),

docs/registries/conversion.md

@@ -192,7 +192,7 @@ See more about Golang Layout on the [official documentation](https://go.dev/src/
 
 toLocalDate converts a string to a time.Time object based on a format specification and the local timezone.
 
-<table data-header-hidden><thead><tr><th width="162">Name</th><th>Value</th></tr></thead><tbody><tr><td>Signature</td><td><pre class="language-go"><code class="lang-go">ToLocalDate(fmt, timezone, str string) (time.Time, error)
+<table data-header-hidden><thead><tr><th width="162">Name</th><th>Value</th></tr></thead><tbody><tr><td>Signature</td><td><pre class="language-go"><code class="lang-go">ToLocalDate(layout, timezone, value string) (time.Time, error)
 </code></pre></td></tr></tbody></table>
 
 {% tabs %}

docs/registries/time.md

@@ -19,7 +19,7 @@ import "github.com/go-sprout/sprout/registry/time"
 
 The function formats a given date or the current time into a specified format string.
 
-<table data-header-hidden><thead><tr><th width="174">Name</th><th>Value</th></tr></thead><tbody><tr><td>Signature</td><td><pre class="language-go"><code class="lang-go"> Date(fmt string, date any) (string, error)
+<table data-header-hidden><thead><tr><th width="174">Name</th><th>Value</th></tr></thead><tbody><tr><td>Signature</td><td><pre class="language-go"><code class="lang-go"> Date(layout string, date any) (string, error)
 </code></pre></td></tr></tbody></table>
 
 {% tabs %}
@@ -34,7 +34,7 @@ The function formats a given date or the current time into a specified format st
 
 The function formats a given date or the current time into a specified format string for a specified timezone.
 
-<table data-header-hidden><thead><tr><th width="124">Name</th><th>Value</th></tr></thead><tbody><tr><td>Signature</td><td><pre class="language-go"><code class="lang-go">DateInZone(fmt string, date any, zone string) (string, error)
+<table data-header-hidden><thead><tr><th width="124">Name</th><th>Value</th></tr></thead><tbody><tr><td>Signature</td><td><pre class="language-go"><code class="lang-go">DateInZone(layout string, date any, zone string) (string, error)
 </code></pre></td></tr></tbody></table>
 
 {% tabs %}
@@ -121,7 +121,7 @@ The function returns the Unix epoch timestamp for a given date.
 
 The function adjusts a given date by a specified duration, returning the modified date. If the duration format is incorrect, it returns the original date without any changes, in case of must version, an error is returned.
 
-<table data-header-hidden><thead><tr><th width="164">Name</th><th>Value</th></tr></thead><tbody><tr><td>Signature</td><td><pre class="language-go"><code class="lang-go">DateModify(fmt string, date time.Time) (time.Time, error)
+<table data-header-hidden><thead><tr><th width="164">Name</th><th>Value</th></tr></thead><tbody><tr><td>Signature</td><td><pre class="language-go"><code class="lang-go">DateModify(layout string, date time.Time) (time.Time, error)
 </code></pre></td></tr></tbody></table>
 
 {% tabs %}

handler.go

@@ -3,7 +3,7 @@ package sprout
 import (
 	"log/slog"
 	"slices"
-	gostrings "strings"
+	"strings"
 
 	"golang.org/x/text/cases"
 	"golang.org/x/text/language"
@@ -259,7 +259,7 @@ func safeFuncName(name string) string {
 		return ""
 	}
 
-	var b gostrings.Builder
+	var b strings.Builder
 	b.Grow(len(name) + 4)
 
 	b.WriteString("safe")

pesticide/time_test_helpers.go

@@ -0,0 +1,15 @@
+package pesticide
+
+import (
+	"testing"
+	"time"
+)
+
+// ForceTimeLocal temporarily sets [time.Local] for test purpose.
+func ForceTimeLocal(t *testing.T, local *time.Location) {
+	t.Helper()
+
+	originalLocal := time.Local
+	time.Local = local
+	t.Cleanup(func() { time.Local = originalLocal })
+}

registry/conversion/functions.go

@@ -170,7 +170,7 @@ func (cr *ConversionRegistry) ToString(value any) string {
 //
 // Parameters:
 //
-//	fmt string - the date format string.
+//	layout string - the date format string.
 //	value string - the date string to parse.
 //
 // Returns:
@@ -181,16 +181,16 @@ func (cr *ConversionRegistry) ToString(value any) string {
 // For an example of this function in a Go template, refer to [Sprout Documentation: toDate].
 //
 // [Sprout Documentation: toDate]: https://docs.atom.codes/sprout/registries/conversion#todate
-func (cr *ConversionRegistry) ToDate(fmt, value string) (time.Time, error) {
-	return time.ParseInLocation(fmt, value, time.Local)
+func (cr *ConversionRegistry) ToDate(layout, value string) (time.Time, error) {
+	return time.ParseInLocation(layout, value, time.Local)
 }
 
 // ToLocalDate converts a string to a time.Time object based on a format specification
 // and the local timezone.
 //
 // Parameters:
 //
-//	fmt string - the date format string.
+//	layout string - the date format string.
 //	value string - the date string to parse.
 //
 // Returns:
@@ -201,13 +201,13 @@ func (cr *ConversionRegistry) ToDate(fmt, value string) (time.Time, error) {
 // For an example of this function in a Go template, refer to [Sprout Documentation: toLocalDate].
 //
 // [Sprout Documentation: toLocalDate]: https://docs.atom.codes/sprout/registries/conversion#tolocaldate
-func (cr *ConversionRegistry) ToLocalDate(fmt, timezone, value string) (time.Time, error) {
+func (cr *ConversionRegistry) ToLocalDate(layout, timezone, value string) (time.Time, error) {
 	location, err := time.LoadLocation(timezone)
 	if err != nil {
 		return time.Time{}, err
 	}
 
-	return time.ParseInLocation(fmt, value, location)
+	return time.ParseInLocation(layout, value, location)
 }
 
 // ToDuration converts a value to a time.Duration.

registry/conversion/functions_test.go

@@ -3,6 +3,9 @@ package conversion_test
 import (
 	"fmt"
 	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
 
 	"github.com/go-sprout/sprout/pesticide"
 	"github.com/go-sprout/sprout/registry/conversion"
@@ -120,34 +123,152 @@ func TestToString(t *testing.T) {
 }
 
 func TestToDate(t *testing.T) {
-	tc := []pesticide.TestCase{
-		{
-			Name:           "TestDate",
-			Input:          `{{$v := toDate "2006-01-02" .V }}{{typeOf $v}}-{{$v}}`,
-			Data:           map[string]any{"V": "2024-05-09"},
-			ExpectedOutput: "time.Time-2024-05-09 00:00:00 +0000 UTC",
-		},
-		{
-			Name:           "TestDate",
-			Input:          `{{$v := toDate "2006-01-02 15:04:05 MST" .V }}{{typeOf $v}}-{{$v}}`,
-			Data:           map[string]any{"V": "2024-05-09 00:00:00 UTC"},
-			ExpectedOutput: "time.Time-2024-05-09 00:00:00 +0000 UTC",
-		},
-		{
-			Name:        "TestInvalidValue",
-			Input:       `{{$v := toDate "2006-01-02" .V }}{{typeOf $v}}-{{$v}}`,
-			Data:        map[string]any{"V": ""},
-			ExpectedErr: "cannot parse \"\" as \"2006\"",
-		},
-		{
-			Name:        "TestInvalidLayout",
-			Input:       `{{$v := toDate "invalid" .V }}{{typeOf $v}}-{{$v}}`,
-			Data:        map[string]any{"V": "2024-05-09"},
-			ExpectedErr: "cannot parse \"2024-05-09\" as \"invalid\"",
-		},
-	}
+	t.Run("dates with numeric timezone offset", func(t *testing.T) {
+		// Please refer to https://pkg.go.dev/time#Parse
+		// When parsing a time with a zone offset like -0700,
+		// if the offset corresponds to a time zone used by the current location (Local),
+		// then Parse uses that location and zone in the returned time.
+		// Otherwise it records the time as being in a fabricated location with time fixed at the given zone offset.
 
-	pesticide.RunTestCases(t, conversion.NewRegistry(), tc)
+		// So we have to temporarily force time.Local a known timezone
+		// to validate the behavior of toDate function
+		local, err := time.LoadLocation("America/New_York")
+		require.NoError(t, err)
+
+		// temporarily force time.Local to New York
+		pesticide.ForceTimeLocal(t, local)
+
+		tc := []pesticide.TestCase{
+			{
+				Name:           "date with UTC timezone",
+				Input:          `{{$v := toDate "2006-01-02 15:04:05 -0700" .V }}{{typeOf $v}}-{{$v}}`,
+				Data:           map[string]any{"V": "2024-05-09 00:00:00 +0000"},
+				ExpectedOutput: "time.Time-2024-05-09 00:00:00 +0000 +0000",
+			},
+			{
+				Name:           "date with non-UTC timezone equal to local timezone",
+				Input:          `{{$v := toDate "2006-01-02 15:04:05 -0700" .V }}{{typeOf $v}}-{{$v}}`,
+				Data:           map[string]any{"V": "2024-05-09 00:00:00 -0400"},
+				ExpectedOutput: "time.Time-2024-05-09 00:00:00 -0400 EDT",
+			},
+			{
+				Name:           "date with non-UTC timezone different than local",
+				Input:          `{{$v := toDate "2006-01-02 15:04:05 -0700" .V }}{{typeOf $v}}-{{$v}}`,
+				Data:           map[string]any{"V": "2024-05-09 00:00:00 -0700"},
+				ExpectedOutput: "time.Time-2024-05-09 00:00:00 -0700 -0700",
+			},
+		}
+
+		pesticide.RunTestCases(t, conversion.NewRegistry(), tc)
+	})
+
+	t.Run("dates with abbreviated timezone", func(t *testing.T) {
+		// Please refer to https://pkg.go.dev/time#Parse
+		// When parsing a time with a zone abbreviation like MST,
+		// if the zone abbreviation has a defined offset in the current location,
+		// then that offset is used.
+		// The zone abbreviation "UTC" is recognized as UTC regardless of location.
+		// To avoid such problems, prefer time layouts that use a numeric zone offset, or use ParseInLocation.
+
+		// So we have to temporarily force time.Local a known timezone
+		// to validate the behavior of toDate function
+		local, err := time.LoadLocation("America/New_York")
+		require.NoError(t, err)
+
+		// temporarily force time.Local to New York
+		pesticide.ForceTimeLocal(t, local)
+
+		tc := []pesticide.TestCase{
+			{
+				Name:           "date with UTC timezone",
+				Input:          `{{$v := toDate "2006-01-02 15:04:05 MST" .V }}{{typeOf $v}}-{{$v}}`,
+				Data:           map[string]any{"V": "2024-05-09 00:00:00 UTC"},
+				ExpectedOutput: "time.Time-2024-05-09 00:00:00 +0000 UTC",
+			},
+			{
+				Name:           "date with non-UTC timezone equal to local timezone",
+				Input:          `{{$v := toDate "2006-01-02 15:04:05 MST" .V }}{{typeOf $v}}-{{$v}}`,
+				Data:           map[string]any{"V": "2024-05-09 00:00:00 EDT"},
+				ExpectedOutput: "time.Time-2024-05-09 00:00:00 -0400 EDT",
+			},
+			{
+				Name:           "date with non-UTC timezone different than local",
+				Input:          `{{$v := toDate "2006-01-02 15:04:05 MST" .V }}{{typeOf $v}}-{{$v}}`,
+				Data:           map[string]any{"V": "2024-05-09 00:00:00 MST"},
+				ExpectedOutput: "time.Time-2024-05-09 00:00:00 +0000 MST",
+			},
+		}
+
+		pesticide.RunTestCases(t, conversion.NewRegistry(), tc)
+	})
+
+	t.Run("dates without timezone (local time should be assumed)", func(t *testing.T) {
+		t.Run("UTC", func(t *testing.T) {
+			// temporarily force time.Local to UTC
+			pesticide.ForceTimeLocal(t, time.UTC)
+
+			tc := []pesticide.TestCase{
+				{
+					Name:           "short date",
+					Input:          `{{$v := toDate "2006-01-02" .V }}{{typeOf $v}}-{{$v}}`,
+					Data:           map[string]any{"V": "2024-05-09"},
+					ExpectedOutput: "time.Time-2024-05-09 00:00:00 +0000 UTC",
+				},
+				{
+					Name:           "datetime ",
+					Input:          `{{$v := toDate "2006-01-02 15:04:05" .V }}{{typeOf $v}}-{{$v}}`,
+					Data:           map[string]any{"V": "2024-05-09 01:02:03"},
+					ExpectedOutput: "time.Time-2024-05-09 01:02:03 +0000 UTC",
+				},
+			}
+
+			pesticide.RunTestCases(t, conversion.NewRegistry(), tc)
+		})
+
+		t.Run("New York timezone", func(t *testing.T) {
+			local, err := time.LoadLocation("America/New_York")
+			require.NoError(t, err)
+
+			// temporarily force time.Local to New York
+			pesticide.ForceTimeLocal(t, local)
+
+			tc := []pesticide.TestCase{
+				{
+					Name:           "short date",
+					Input:          `{{$v := toDate "2006-01-02" .V }}{{typeOf $v}}-{{$v}}`,
+					Data:           map[string]any{"V": "2024-05-09"},
+					ExpectedOutput: "time.Time-2024-05-09 00:00:00 -0400 EDT",
+				},
+				{
+					Name:           "datetime ",
+					Input:          `{{$v := toDate "2006-01-02 15:04:05" .V }}{{typeOf $v}}-{{$v}}`,
+					Data:           map[string]any{"V": "2024-05-09 01:02:03"},
+					ExpectedOutput: "time.Time-2024-05-09 01:02:03 -0400 EDT",
+				},
+			}
+
+			pesticide.RunTestCases(t, conversion.NewRegistry(), tc)
+		})
+	})
+
+	t.Run("invalid layout", func(t *testing.T) {
+		tc := []pesticide.TestCase{
+			{
+				Name:        "TestInvalidValue",
+				Input:       `{{$v := toDate "2006-01-02" .V }}{{typeOf $v}}-{{$v}}`,
+				Data:        map[string]any{"V": ""},
+				ExpectedErr: `cannot parse "" as "2006"`,
+			},
+			{
+				Name:        "TestInvalidLayout",
+				Input:       `{{$v := toDate "invalid" .V }}{{typeOf $v}}-{{$v}}`,
+				Data:        map[string]any{"V": "2024-05-09"},
+				ExpectedErr: `cannot parse "2024-05-09" as "invalid"`,
+			},
+		}
+
+		pesticide.RunTestCases(t, conversion.NewRegistry(), tc)
+	})
 }
 
 func TestToLocalDate(t *testing.T) {