Merge remote-tracking branch 'origin' into github-actions-windows

.github/.codecov.yml

@@ -0,0 +1 @@
+comment: false

.github/workflows/cli.yml

@@ -1,6 +1,10 @@
 name: Run Tests
 
 on:
+  push:
+    branches:
+      - master
+      - v1
   pull_request:
     branches:
       - master
@@ -47,40 +51,38 @@ jobs:
           curl -L -o gfmrun.exe "https://github.com/urfave/gfmrun/releases/download/v1.2.14/gfmrun-windows-amd64-v1.2.14.exe"
           npm install markdown-toc
 
-      - name: Run Tests (v1) (Linux / MacOS)
+      - name: Run Tests
-        if: contains(github.base_ref, 'v1') && matrix.os != 'windows-latest'
         run: |
           go run build.go vet
           go run build.go test
+
+      - name: Run Tests (v1) (Linux / MacOS)
+        if: contains(github.base_ref, 'v1') && matrix.os != 'windows-latest'
+        run: |
           go run build.go gfmrun docs/v1/manual.md
           go run build.go toc docs/v1/manual.md
 
       - name: Run Tests (v1) (Windows)
         if: contains(github.base_ref, 'v1') && matrix.os == 'windows-latest'
         run: |
-          go run build.go vet
-          go run build.go test
           go run build.go gfmrun docs\v1\manual.md
           go run build.go toc docs\v1\manual.md
 
       - name: Run Tests (v2) (Linux / MacOS)
         if: contains(github.base_ref, 'master') && matrix.os != 'windows-latest'
         run: |
-          go run build.go vet
-          go run build.go test
           go run build.go gfmrun docs/v2/manual.md
           go run build.go toc docs/v2/manual.md
 
       - name: Run Tests (v2) (Windows)
         if: contains(github.base_ref, 'master') && matrix.os == 'windows-latest'
         run: |
-          go run build.go vet
-          go run build.go test
           go run build.go gfmrun docs/v2/manual.md
           go run build.go toc docs/v2/manual.md
 
-      - name: Send Coverage Report
+      - name: Upload coverage to Codecov
-        if: success()
+        if: success() && matrix.go == 1.13 && matrix.os == 'ubuntu-latest'
-        env:
+        uses: codecov/codecov-action@v1
-          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+        with:
-        run: bash <(curl -s https://codecov.io/bash)
+          token: 0a8cc73b-bb7c-480b-8626-38a461643761
+          fail_ci_if_error: true

README.md

@@ -1,7 +1,6 @@
 cli
 ===
 
-[![Build Status](https://travis-ci.org/urfave/cli.svg?branch=master)](https://travis-ci.org/urfave/cli)
 [![Windows Build Status](https://ci.appveyor.com/api/projects/status/rtgk5xufi932pb2v?svg=true)](https://ci.appveyor.com/project/urfave/cli)
 
 [![GoDoc](https://godoc.org/github.com/urfave/cli?status.svg)](https://godoc.org/github.com/urfave/cli)
@@ -20,6 +19,12 @@ Usage documentation exists for each major version. Don't know what version you'r
 - `v2` - [./docs/v2/manual.md](./docs/v2/manual.md)
 - `v1` - [./docs/v1/manual.md](./docs/v1/manual.md)
 
+## Installation
+
+Make sure you have a working Go environment.  Go version 1.11+ is supported. [See the install instructions for Go](http://golang.org/doc/install.html).
+
+Go Modules are strongly recommended when using this package. [See the go blog guide on using Go Modules](https://blog.golang.org/using-go-modules).
+
 ### Using `v2` releases
 
 ```
@@ -37,7 +42,7 @@ import (
 ### Using `v1` releases
 
 ```
-$ go get github.com/urfave/cli
+$ GO111MODULE=on go get github.com/urfave/cli
 ```
 
 ```go
@@ -48,11 +53,6 @@ import (
 ...
 ```
 
-## Installation
-
-Make sure you have a working Go environment.  Go version 1.10+ is supported.  [See
-the install instructions for Go](http://golang.org/doc/install.html).
-
 ### GOPATH
 
 Make sure your `PATH` includes the `$GOPATH/bin` directory so your commands can
@@ -64,5 +64,5 @@ export PATH=$PATH:$GOPATH/bin
 ### Supported platforms
 
 cli is tested against multiple versions of Go on Linux, and against the latest
-released version of Go on OS X and Windows.  For full details, see
+released version of Go on OS X and Windows. This project uses Github Actions for
-[`./.travis.yml`](./.travis.yml) and [`./appveyor.yml`](./appveyor.yml).
+builds. For more build info, please look at the [./.github/workflows/cli.yml](https://github.com/urfave/cli/blob/master/.github/workflows/cli.yml).

app.go

@@ -1,6 +1,7 @@
 package cli
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"io"
@@ -12,7 +13,7 @@ import (
 )
 
 var (
-	changeLogURL            = "https://github.com/urfave/cli/blob/master/CHANGELOG.md"
+	changeLogURL            = "https://github.com/urfave/cli/blob/master/docs/CHANGELOG.md"
 	appActionDeprecationURL = fmt.Sprintf("%s#deprecated-cli-app-action-signature", changeLogURL)
 	contactSysadmin         = "This is an error in the application.  Please contact the distributor of this application if this is not you."
 	errInvalidActionType    = NewExitError("ERROR invalid Action type. "+
@@ -207,6 +208,13 @@ func (a *App) useShortOptionHandling() bool {
 // Run is the entry point to the cli app. Parses the arguments slice and routes
 // to the proper flag/args combination
 func (a *App) Run(arguments []string) (err error) {
+	return a.RunContext(context.Background(), arguments)
+}
+
+// RunContext is like Run except it takes a Context that will be
+// passed to its commands and sub-commands. Through this, you can
+// propagate timeouts and cancellation requests
+func (a *App) RunContext(ctx context.Context, arguments []string) (err error) {
 	a.Setup()
 
 	// handle the completion flag separately from the flagset since
@@ -224,7 +232,7 @@ func (a *App) Run(arguments []string) (err error) {
 
 	err = parseIter(set, a, arguments[1:], shellComplete)
 	nerr := normalizeFlags(a.Flags, set)
-	context := NewContext(a, set, nil)
+	context := NewContext(a, set, &Context{Context: ctx})
 	if nerr != nil {
 		_, _ = fmt.Fprintln(a.Writer, nerr)
 		_ = ShowAppHelp(context)

app_test.go

@@ -7,7 +7,6 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
-	"log"
 	"os"
 	"reflect"
 	"strings"
@@ -2121,7 +2120,7 @@ func TestWhenExitSubCommandWithCodeThenAppQuitUnexpectedly(t *testing.T) {
 	var exitCodeFromExitErrHandler int
 	app.ExitErrHandler = func(c *Context, err error) {
 		if exitErr, ok := err.(ExitCoder); ok {
-			log.Print(exitErr)
+			t.Log(exitErr)
 			exitCodeFromExitErrHandler = exitErr.ExitCode()
 		}
 	}

appveyor.yml

@@ -20,7 +20,6 @@ install:
   - go version
   - go env
   - go get github.com/urfave/gfmrun/cmd/gfmrun
-  - go get golang.org/x/tools/cmd/goimports
   - go mod tidy
 
 build_script:

category.go

@@ -1,5 +1,6 @@
 package cli
 
+// CommandCategories interface allows for category manipulation
 type CommandCategories interface {
 	// AddCommand adds a command to a category, creating a new category if necessary.
 	AddCommand(category string, command *Command)

context.go

@@ -5,10 +5,7 @@ import (
 	"errors"
 	"flag"
 	"fmt"
-	"os"
-	"os/signal"
 	"strings"
-	"syscall"
 )
 
 // Context is a type that is passed through to
@@ -31,19 +28,15 @@ func NewContext(app *App, set *flag.FlagSet, parentCtx *Context) *Context {
 	if parentCtx != nil {
 		c.Context = parentCtx.Context
 		c.shellComplete = parentCtx.shellComplete
+		if parentCtx.flagSet == nil {
+			parentCtx.flagSet = &flag.FlagSet{}
+		}
 	}
 
 	c.Command = &Command{}
 
 	if c.Context == nil {
-		ctx, cancel := context.WithCancel(context.Background())
+		c.Context = context.Background()
-		go func() {
-			defer cancel()
-			sigs := make(chan os.Signal, 1)
-			signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
-			<-sigs
-		}()
-		c.Context = ctx
 	}
 
 	return c

context_test.go

@@ -344,6 +344,81 @@ func TestContextPropagation(t *testing.T) {
 	}
 }
 
+func TestContextAttributeAccessing(t *testing.T) {
+	tdata := []struct {
+		testCase        string
+		setBoolInput    string
+		ctxBoolInput    string
+		newContextInput *Context
+	}{
+		{
+			testCase:        "empty",
+			setBoolInput:    "",
+			ctxBoolInput:    "",
+			newContextInput: nil,
+		},
+		{
+			testCase:        "empty_with_background_context",
+			setBoolInput:    "",
+			ctxBoolInput:    "",
+			newContextInput: &Context{Context: context.Background()},
+		},
+		{
+			testCase:        "empty_set_bool_and_present_ctx_bool",
+			setBoolInput:    "",
+			ctxBoolInput:    "ctx-bool",
+			newContextInput: nil,
+		},
+		{
+			testCase:        "present_set_bool_and_present_ctx_bool_with_background_context",
+			setBoolInput:    "",
+			ctxBoolInput:    "ctx-bool",
+			newContextInput: &Context{Context: context.Background()},
+		},
+		{
+			testCase:        "present_set_bool_and_present_ctx_bool",
+			setBoolInput:    "ctx-bool",
+			ctxBoolInput:    "ctx-bool",
+			newContextInput: nil,
+		},
+		{
+			testCase:        "present_set_bool_and_present_ctx_bool_with_background_context",
+			setBoolInput:    "ctx-bool",
+			ctxBoolInput:    "ctx-bool",
+			newContextInput: &Context{Context: context.Background()},
+		},
+		{
+			testCase:        "present_set_bool_and_different_ctx_bool",
+			setBoolInput:    "ctx-bool",
+			ctxBoolInput:    "not-ctx-bool",
+			newContextInput: nil,
+		},
+		{
+			testCase:        "present_set_bool_and_different_ctx_bool_with_background_context",
+			setBoolInput:    "ctx-bool",
+			ctxBoolInput:    "not-ctx-bool",
+			newContextInput: &Context{Context: context.Background()},
+		},
+	}
+
+	for _, test := range tdata {
+		t.Run(test.testCase, func(t *testing.T) {
+			// setup
+			set := flag.NewFlagSet("some-flag-set-name", 0)
+			set.Bool(test.setBoolInput, false, "usage documentation")
+			ctx := NewContext(nil, set, test.newContextInput)
+
+			// logic under test
+			value := ctx.Bool(test.ctxBoolInput)
+
+			// assertions
+			if value != false {
+				t.Errorf("expected \"value\" to be false, but it was not")
+			}
+		})
+	}
+}
+
 func TestCheckRequiredFlags(t *testing.T) {
 	tdata := []struct {
 		testCase              string

docs.go

@@ -48,8 +48,8 @@ func (a *App) writeDocTemplate(w io.Writer) error {
 	return t.ExecuteTemplate(w, name, &cliTemplate{
 		App:          a,
 		Commands:     prepareCommands(a.Commands, 0),
-		GlobalArgs:   prepareArgsWithValues(a.Flags),
+		GlobalArgs:   prepareArgsWithValues(a.VisibleFlags()),
-		SynopsisArgs: prepareArgsSynopsis(a.Flags),
+		SynopsisArgs: prepareArgsSynopsis(a.VisibleFlags()),
 	})
 }
 

docs/CHANGELOG.md

@@ -6,6 +6,33 @@
 
 View [unreleased 2.X] series changes.
 
+## [2.1.1] - 2019-12-24
+
+### Fixed
+
+* Fixed a `Context` regression introduced in `v2.1.0` in [urfave/cli/pull/1014](https://github.com/urfave/cli/pull/1014) via [@lynncyrin](https://github.com/lynncyrin)
+
+## [2.1.0] - 2019-12-24
+
+These release notes were written for the git hash [ae84df4cef4a2a6f1a0cb1d41ea0f3af8755e5a8](https://github.com/urfave/cli/tree/ae84df4cef4a2a6f1a0cb1d41ea0f3af8755e5a8)
+
+### Fixed
+
+* Fixed some golint errors in [urfave/cli/pull/988](https://github.com/urfave/cli/pull/988) via [@liamchampton](https://github.com/liamchampton)
+* Fixed a panic with flag completion [urfave/cli/pull/946](https://github.com/urfave/cli/pull/946) via [@unRob](https://github.com/unRob)
+
+### Changed
+
+* Changed docs generation to use visible flags in [urfave/cli/pull/999](https://github.com/urfave/cli/pull/999) via [@subpop](https://github.com/subpop)
+* Changed `App.Run` to use an optional context for timeouts and cancellation in [urfave/cli/pull/975](https://github.com/urfave/cli/pull/975) via [@marwan-at-work](https://github.com/marwan-at-work)
+* Changed version info to be hidden if the user has not defined a version in [urfave/cli/pull/955](https://github.com/urfave/cli/pull/955) via [@asahasrabuddhe](https://github.com/asahasrabuddhe)
+* Changed docs generation to take into account multiple authors in [urfave/cli/pull/900](https://github.com/urfave/cli/pull/900) via [@saschagrunert](https://github.com/saschagrunert)
+* Changed context to expose a `Value` accessor in [urfave/cli/pull/741](https://github.com/urfave/cli/pull/741) via [@corruptmemory](https://github.com/corruptmemory)
+
+### Added
+
+* Added timestamp flag in [urfave/cli/pull/987](https://github.com/urfave/cli/pull/987) via [@drov0](https://github.com/drov0)
+
 ## [2.0.0] - 2019-11-17
 
 The V2 changes were all shipped in [urfave/cli/pull/892](https://github.com/urfave/cli/pull/892), which was created with the effort of over a dozen participants! They are:
@@ -520,7 +547,9 @@ signature of `func(*cli.Context) error`, as defined by `cli.ActionFunc`.
 ### Added
 - Initial implementation.
 
-[unreleased 2.X]: https://github.com/urfave/cli/compare/v2.0.0...HEAD
+[unreleased 2.X]: https://github.com/urfave/cli/compare/v2.1.1...HEAD
+[2.1.1]: https://github.com/urfave/cli/compare/v2.1.0...v2.1.1
+[2.1.0]: https://github.com/urfave/cli/compare/v2.0.0...v2.1.0
 [2.0.0]: https://github.com/urfave/cli/compare/v1.22.2...v2.0.0
 
 [unreleased 1.22.X]: https://github.com/urfave/cli/compare/v1.22.2...v1

docs/v2/manual.md

@@ -13,6 +13,7 @@ cli v2 manual
     + [Values from the Environment](#values-from-the-environment)
     + [Values from files](#values-from-files)
     + [Values from alternate input sources (YAML, TOML, and others)](#values-from-alternate-input-sources-yaml-toml-and-others)
+    + [Required Flags](#required-flags)
     + [Default Values for help output](#default-values-for-help-output)
     + [Precedence](#precedence)
   * [Subcommands](#subcommands)
@@ -641,6 +642,63 @@ func main() {
 }
 ```
 
+#### Required Flags
+
+You can make a flag required by setting the `Required` field to `true`. If a user
+does not provide a required flag, they will be shown an error message.
+
+Take for example this app that reqiures the `lang` flag:
+
+<!-- {
+  "error": "Required flag \"lang\" not set"
+} -->
+```go
+package main
+
+import (
+  "log"
+  "os"
+  "strings"
+
+  "github.com/urfave/cli"
+)
+
+func main() {
+  app := cli.NewApp()
+
+  app.Flags = []cli.Flag {
+    cli.StringFlag{
+      Name: "lang",
+      Value: "english",
+      Usage: "language for the greeting",
+      Required: true,
+    },
+  }
+
+  app.Action = func(c *cli.Context) error {
+    var output string
+    if c.String("lang") == "spanish" {
+      output = "Hola"
+    } else {
+      output = "Hello"
+    }
+    fmt.Println(output)
+    return nil
+  }
+
+  err := app.Run(os.Args)
+  if err != nil {
+    log.Fatal(err)
+  }
+}
+```
+
+If the app is run without the `lang` flag, the user will see the following message
+
+```
+Required flag "lang" not set
+```
+
 #### Default Values for help output
 
 Sometimes it's useful to specify a flag's default help-text value within the flag declaration. This can be useful if the default value for a flag is a computed value. The default value can be set via the `DefaultText` struct field.
@@ -1402,13 +1460,15 @@ func main() {
       cli.ShowVersion(c)
 
       fmt.Printf("%#v\n", c.App.Command("doo"))
-      if c.Bool("infinite") {
+      // // uncomment when https://github.com/urfave/cli/pull/1014 is released
-        c.App.Run([]string{"app", "doo", "wop"})
+      // if c.Bool("infinite") {
-      }
+      // 	c.App.Run([]string{"app", "doo", "wop"})
+      // }
 
-      if c.Bool("forevar") {
+      // // uncomment when https://github.com/urfave/cli/pull/1014 is released
-        c.App.RunAsSubcommand(c)
+      // if c.Bool("forevar") {
-      }
+      // 	c.App.RunAsSubcommand(c)
+      // }
       c.App.Setup()
       fmt.Printf("%#v\n", c.App.VisibleCategories())
       fmt.Printf("%#v\n", c.App.VisibleCommands())
@@ -1424,28 +1484,29 @@ func main() {
       set := flag.NewFlagSet("contrive", 0)
       nc := cli.NewContext(c.App, set, c)
 
-      fmt.Printf("%#v\n", nc.Args())
+      // // uncomment when https://github.com/urfave/cli/pull/1014 is released
-      fmt.Printf("%#v\n", nc.Bool("nope"))
+      // fmt.Printf("%#v\n", nc.Args())
-      fmt.Printf("%#v\n", !nc.Bool("nerp"))
+      // fmt.Printf("%#v\n", nc.Bool("nope"))
-      fmt.Printf("%#v\n", nc.Duration("howlong"))
+      // fmt.Printf("%#v\n", !nc.Bool("nerp"))
-      fmt.Printf("%#v\n", nc.Float64("hay"))
+      // fmt.Printf("%#v\n", nc.Duration("howlong"))
-      fmt.Printf("%#v\n", nc.Generic("bloop"))
+      // fmt.Printf("%#v\n", nc.Float64("hay"))
-      fmt.Printf("%#v\n", nc.Int64("bonk"))
+      // fmt.Printf("%#v\n", nc.Generic("bloop"))
-      fmt.Printf("%#v\n", nc.Int64Slice("burnks"))
+      // fmt.Printf("%#v\n", nc.Int64("bonk"))
-      fmt.Printf("%#v\n", nc.Int("bips"))
+      // fmt.Printf("%#v\n", nc.Int64Slice("burnks"))
-      fmt.Printf("%#v\n", nc.IntSlice("blups"))
+      // fmt.Printf("%#v\n", nc.Int("bips"))
-      fmt.Printf("%#v\n", nc.String("snurt"))
+      // fmt.Printf("%#v\n", nc.IntSlice("blups"))
-      fmt.Printf("%#v\n", nc.StringSlice("snurkles"))
+      // fmt.Printf("%#v\n", nc.String("snurt"))
-      fmt.Printf("%#v\n", nc.Uint("flub"))
+      // fmt.Printf("%#v\n", nc.StringSlice("snurkles"))
-      fmt.Printf("%#v\n", nc.Uint64("florb"))
+      // fmt.Printf("%#v\n", nc.Uint("flub"))
-
+      // fmt.Printf("%#v\n", nc.Uint64("florb"))
-      fmt.Printf("%#v\n", nc.FlagNames())
-      fmt.Printf("%#v\n", nc.IsSet("wat"))
-      fmt.Printf("%#v\n", nc.Set("wat", "nope"))
-      fmt.Printf("%#v\n", nc.NArg())
-      fmt.Printf("%#v\n", nc.NumFlags())
-      fmt.Printf("%#v\n", nc.Lineage()[1])
 
+      // // uncomment when https://github.com/urfave/cli/pull/1014 is released
+      // fmt.Printf("%#v\n", nc.FlagNames())
+      // fmt.Printf("%#v\n", nc.IsSet("wat"))
+      // fmt.Printf("%#v\n", nc.Set("wat", "nope"))
+      // fmt.Printf("%#v\n", nc.NArg())
+      // fmt.Printf("%#v\n", nc.NumFlags())
+      // fmt.Printf("%#v\n", nc.Lineage()[1])
       nc.Set("wat", "also-nope")
 
       ec := cli.Exit("ohwell", 86)

docs_test.go

@@ -23,6 +23,10 @@ func testApp() *App {
 			Aliases: []string{"b"},
 			Usage:   "another usage text",
 		},
+		&BoolFlag{
+			Name:   "hidden-flag",
+			Hidden: true,
+		},
 	}
 	app.Commands = []*Command{{
 		Aliases: []string{"c"},

errors.go

@@ -48,6 +48,7 @@ func (m *multiError) Errors() []error {
 	return errs
 }
 
+// ErrorFormatter is the interface that will suitably format the error output
 type ErrorFormatter interface {
 	Format(s fmt.State, verb rune)
 }

flag_float64.go

@@ -22,7 +22,7 @@ type Float64Flag struct {
 }
 
 // IsSet returns whether or not the flag has been set through env or file
-func (f *Float64Flag)IsSet() bool {
+func (f *Float64Flag) IsSet() bool {
 	return f.HasBeenSet
 }
 

flag_path.go

@@ -72,7 +72,7 @@ func (f *PathFlag) Apply(set *flag.FlagSet) error {
 	return nil
 }
 
-// String looks up the value of a local PathFlag, returns
+// Path looks up the value of a local PathFlag, returns
 // "" if not found
 func (c *Context) Path(name string) string {
 	if fs := lookupFlagSet(name, c); fs != nil {

flag_test.go

@@ -1678,3 +1678,58 @@ func TestInt64Slice_Serialized_Set(t *testing.T) {
 		t.Fatalf("pre and post serialization do not match: %v != %v", sl0, sl1)
 	}
 }
+
+func TestTimestamp_set(t *testing.T) {
+	ts := Timestamp{
+		timestamp:  nil,
+		hasBeenSet: false,
+		layout:     "Jan 2, 2006 at 3:04pm (MST)",
+	}
+
+	time1 := "Feb 3, 2013 at 7:54pm (PST)"
+	if err := ts.Set(time1); err != nil {
+		t.Fatalf("Failed to parse time %s with layout %s", time1, ts.layout)
+	}
+	if ts.hasBeenSet == false {
+		t.Fatalf("hasBeenSet is not true after setting a time")
+	}
+
+	ts.hasBeenSet = false
+	ts.SetLayout(time.RFC3339)
+	time2 := "2006-01-02T15:04:05Z"
+	if err := ts.Set(time2); err != nil {
+		t.Fatalf("Failed to parse time %s with layout %s", time2, ts.layout)
+	}
+	if ts.hasBeenSet == false {
+		t.Fatalf("hasBeenSet is not true after setting a time")
+	}
+}
+
+func TestTimestampFlagApply(t *testing.T) {
+	expectedResult, _ :=  time.Parse(time.RFC3339, "2006-01-02T15:04:05Z")
+	fl := TimestampFlag{Name: "time", Aliases: []string{"t"}, Layout: time.RFC3339}
+	set := flag.NewFlagSet("test", 0)
+	_ = fl.Apply(set)
+
+	err := set.Parse([]string{"--time", "2006-01-02T15:04:05Z"})
+	expect(t, err, nil)
+	expect(t, *fl.Value.timestamp, expectedResult)
+}
+
+func TestTimestampFlagApply_Fail_Parse_Wrong_Layout(t *testing.T) {
+	fl := TimestampFlag{Name: "time", Aliases: []string{"t"}, Layout: "randomlayout"}
+	set := flag.NewFlagSet("test", 0)
+	_ = fl.Apply(set)
+
+	err := set.Parse([]string{"--time", "2006-01-02T15:04:05Z"})
+	expect(t, err, fmt.Errorf("invalid value \"2006-01-02T15:04:05Z\" for flag -time: parsing time \"2006-01-02T15:04:05Z\" as \"randomlayout\": cannot parse \"2006-01-02T15:04:05Z\" as \"randomlayout\""))
+}
+
+func TestTimestampFlagApply_Fail_Parse_Wrong_Time(t *testing.T) {
+	fl := TimestampFlag{Name: "time", Aliases: []string{"t"}, Layout: "Jan 2, 2006 at 3:04pm (MST)"}
+	set := flag.NewFlagSet("test", 0)
+	_ = fl.Apply(set)
+
+	err := set.Parse([]string{"--time", "2006-01-02T15:04:05Z"})
+	expect(t, err, fmt.Errorf("invalid value \"2006-01-02T15:04:05Z\" for flag -time: parsing time \"2006-01-02T15:04:05Z\" as \"Jan 2, 2006 at 3:04pm (MST)\": cannot parse \"2006-01-02T15:04:05Z\" as \"Jan\""))
+}

flag_timestamp.go

@@ -0,0 +1,152 @@
+package cli
+
+import (
+	"flag"
+	"fmt"
+	"time"
+)
+
+// Timestamp wrap to satisfy golang's flag interface.
+type Timestamp struct {
+	timestamp  *time.Time
+	hasBeenSet bool
+	layout     string
+}
+
+// Timestamp constructor
+func NewTimestamp(timestamp time.Time) *Timestamp {
+	return &Timestamp{timestamp: &timestamp}
+}
+
+// Set the timestamp value directly
+func (t *Timestamp) SetTimestamp(value time.Time) {
+	if !t.hasBeenSet {
+		t.timestamp = &value
+		t.hasBeenSet = true
+	}
+}
+
+// Set the timestamp string layout for future parsing
+func (t *Timestamp) SetLayout(layout string) {
+	t.layout = layout
+}
+
+// Parses the string value to timestamp
+func (t *Timestamp) Set(value string) error {
+	timestamp, err := time.Parse(t.layout, value)
+	if err != nil {
+		return err
+	}
+
+	t.timestamp = &timestamp
+	t.hasBeenSet = true
+	return nil
+}
+
+// String returns a readable representation of this value (for usage defaults)
+func (t *Timestamp) String() string {
+	return fmt.Sprintf("%#v", t.timestamp)
+}
+
+// Value returns the timestamp value stored in the flag
+func (t *Timestamp) Value() *time.Time {
+	return t.timestamp
+}
+
+// Get returns the flag structure
+func (t *Timestamp) Get() interface{} {
+	return *t
+}
+
+// TimestampFlag is a flag with type time
+type TimestampFlag struct {
+	Name        string
+	Aliases     []string
+	Usage       string
+	EnvVars     []string
+	FilePath    string
+	Required    bool
+	Hidden      bool
+	Layout      string
+	Value       *Timestamp
+	DefaultText string
+	HasBeenSet  bool
+}
+
+// IsSet returns whether or not the flag has been set through env or file
+func (f *TimestampFlag) IsSet() bool {
+	return f.HasBeenSet
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f *TimestampFlag) String() string {
+	return FlagStringer(f)
+}
+
+// Names returns the names of the flag
+func (f *TimestampFlag) Names() []string {
+	return flagNames(f)
+}
+
+// IsRequired returns whether or not the flag is required
+func (f *TimestampFlag) IsRequired() bool {
+	return f.Required
+}
+
+// TakesValue returns true of the flag takes a value, otherwise false
+func (f *TimestampFlag) TakesValue() bool {
+	return true
+}
+
+// GetUsage returns the usage string for the flag
+func (f *TimestampFlag) GetUsage() string {
+	return f.Usage
+}
+
+// GetValue returns the flags value as string representation and an empty
+// string if the flag takes no value at all.
+func (f *TimestampFlag) GetValue() string {
+	if f.Value != nil {
+		return f.Value.timestamp.String()
+	}
+	return ""
+}
+
+// Apply populates the flag given the flag set and environment
+func (f *TimestampFlag) Apply(set *flag.FlagSet) error {
+	if f.Layout == "" {
+		return fmt.Errorf("timestamp Layout is required")
+	}
+	f.Value = &Timestamp{}
+	f.Value.SetLayout(f.Layout)
+
+	if val, ok := flagFromEnvOrFile(f.EnvVars, f.FilePath); ok {
+		if err := f.Value.Set(val); err != nil {
+			return fmt.Errorf("could not parse %q as timestamp value for flag %s: %s", val, f.Name, err)
+		}
+		f.HasBeenSet = true
+	}
+
+	for _, name := range f.Names() {
+		set.Var(f.Value, name, f.Usage)
+	}
+	return nil
+}
+
+// Timestamp gets the timestamp from a flag name
+func (c *Context) Timestamp(name string) *time.Time {
+	if fs := lookupFlagSet(name, c); fs != nil {
+		return lookupTimestamp(name, fs)
+	}
+	return nil
+}
+
+// Fetches the timestamp value from the local timestampWrap
+func lookupTimestamp(name string, set *flag.FlagSet) *time.Time {
+	f := set.Lookup(name)
+	if f != nil {
+		return (f.Value.(*Timestamp)).Value()
+	}
+	return nil
+}

help.go

@@ -138,7 +138,7 @@ func printFlagSuggestions(lastArg string, flags []Flag, writer io.Writer) {
 		if bflag, ok := flag.(*BoolFlag); ok && bflag.Hidden {
 			continue
 		}
-		for _, name := range flag.Names(){
+		for _, name := range flag.Names() {
 			name = strings.TrimSpace(name)
 			// this will get total count utf8 letters in flag name
 			count := utf8.RuneCountInString(name)