simuluate git diff output

README.md

@@ -70,7 +70,7 @@ _Please note:_ This will install `dyff` based on the latest available code base.
 
   ```bash
   # Setup
-  export KUBECTL_EXTERNAL_DIFF="dyff between --omit-header --set-exit-code"
+  export KUBECTL_EXTERNAL_DIFF="dyff between --omit-header --set-exit-code --kubectl-external-diff"
 
   # Usage
   kubectl diff [...]
@@ -96,12 +96,14 @@ _Please note:_ This will install `dyff` based on the latest available code base.
 
     ```bash
     # Setup...
-    git config --local diff.dyff.command 'dyff_between() { dyff --color on between --omit-header "$2" "$5"; }; dyff_between'
-    echo '*.yml diff=dyff' >> .gitattributes
+    git config --local diff.dyff.command 'dyff git-diff'
+    echo '*.yml diff=dyff'  >> .gitattributes
+    echo '*.yaml diff=dyff' >> .gitattributes
 
     # And have fun, e.g.:
     git log --ext-diff -u
     git show --ext-diff HEAD
+    GIT_CONFIG_PARAMETERS="'color.ui=always'"  git log --ext-diff -u '**/*.yaml' '**/*.yml'
     ```
 
     ![dyff between example of a Git commit](.docs/dyff-between-git-commits-example.png?raw=true "dyff in Git example of an example commit")

go.mod

@@ -14,6 +14,7 @@ require (
 	github.com/mitchellh/hashstructure v1.1.0
 	github.com/onsi/ginkgo v1.16.5
 	github.com/onsi/gomega v1.19.0
+	github.com/pkg/errors v0.9.1
 	github.com/sergi/go-diff v1.2.0
 	github.com/spf13/cobra v1.4.0
 	github.com/texttheater/golang-levenshtein v1.0.1

internal/cmd/between.go

@@ -30,6 +30,7 @@ import (
 
 type betweenCmdOptions struct {
 	swap                     bool
+	kubectlExternalDiff      bool
 	translateListToDocuments bool
 	chroot                   string
 	chrootFrom               string
@@ -118,6 +119,7 @@ func init() {
 
 	// Input documents modification flags
 	betweenCmd.Flags().BoolVar(&betweenCmdSettings.swap, "swap", false, "Swap 'from' and 'to' for comparison")
+	betweenCmd.Flags().BoolVar(&betweenCmdSettings.kubectlExternalDiff, "kubectl-external-diff", false, "Invoked by kubectl external diff, supposed to be configured in KUBECTL_EXTERNAL_DIFF environment variable")
 	betweenCmd.Flags().StringVar(&betweenCmdSettings.chroot, "chroot", "", "change the root level of the input file to another point in the document")
 	betweenCmd.Flags().StringVar(&betweenCmdSettings.chrootFrom, "chroot-of-from", "", "only change the root level of the from input file")
 	betweenCmd.Flags().StringVar(&betweenCmdSettings.chrootTo, "chroot-of-to", "", "only change the root level of the to input file")

internal/cmd/git_diff.go

@@ -0,0 +1,182 @@
+// Copyright © 2019 The Homeport Team
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/gonvenience/wrap"
+	"github.com/gonvenience/ytbx"
+	"github.com/spf13/cobra"
+
+	. "github.com/gonvenience/bunt"
+	"github.com/homeport/dyff/pkg/dyff"
+)
+
+const (
+	// Arbitrary length of the git SHA1 in short format
+	// It does not calculate git-sha1
+	GIT_SHA1_LENGTH = 7
+)
+
+// betweenCmd represents the between command
+var gitDiffCmd = &cobra.Command{
+	Use:   "git-diff name infile1 infile1-sha1 infile1-mode infile2 infile2-sha1 infile2-mode [ rename-to ]",
+	Short: "Supposed to be used as a git diff command for yaml files",
+	Long: `Supposed to be used as a git diff command for yaml files
+Example gitconfig:
+
+[diff "dyff"]
+  command =  dyff git-diff
+
+Example in gitattributes file:
+*.yaml diff=dyff
+*.yml diff=dyff
+
+https://git-scm.com/docs/git-difftool for more information about gif diff
+`,
+	Args: cobra.RangeArgs(7, 9),
+	RunE: func(cmd *cobra.Command, args []string) error {
+
+		fmt.Print(generateGitDiffContext(args))
+		from, to, err := ytbx.LoadFiles(args[1], args[4])
+		if err != nil {
+			return wrap.Errorf(err, "failed to load input files")
+		}
+
+		report, err := dyff.CompareInputFiles(from, to,
+			dyff.IgnoreOrderChanges(reportOptions.ignoreOrderChanges),
+		)
+		if err != nil {
+			return wrap.Errorf(err, "failed to compare input files")
+		}
+
+		reportOptions.omitHeader = true
+		return writeReport(cmd, report)
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(gitDiffCmd)
+
+	GIT_CONFIG_PARAMETERS := os.Getenv("GIT_CONFIG_PARAMETERS")
+	enableColor := strings.Contains(GIT_CONFIG_PARAMETERS, "'color.ui=always'")
+	enableColor = enableColor || strings.Contains(GIT_CONFIG_PARAMETERS, "'color.diff=always'")
+	// color.diff=auto|true|false|xxx will disable color and default to dyff auto
+	// by checking <stdout-is-tty>
+	if !strings.Contains(GIT_CONFIG_PARAMETERS, "'color.diff=always'") && strings.Contains(GIT_CONFIG_PARAMETERS, "'color.diff=") {
+		enableColor = false
+	}
+	if enableColor {
+		SetColorSettings(ON, ON)
+	}
+}
+
+// https://github.com/git/git/blob/6cd33dceed60949e2dbc32e3f0f5e67c4c882e1e/diff.c#L6221
+// https://github.com/git/git/blob/a68dfadae5e95c7f255cf38c9efdcbc2e36d1931/diff.c#L4244-L4250
+/* An external diff command takes:
+ *
+ * diff-cmd name infile1 infile1-sha1 infile1-mode \
+ *               infile2 infile2-sha1 infile2-mode [ rename-to ]
+ *
+ */
+func generateGitDiffContext(args []string) string {
+
+	// Example output format from git diff:
+	/*
+		--------------------------------------------------
+		diff --git a/.github/dependabot.yml b/.github/dependabot.yml
+		new file mode 100644
+		index 0000000..72e0f35
+		--- /dev/null
+		+++ b/.github/dependabot.yml
+
+		--------------------------------------------------
+		diff --git a/.github/dependabot.yml b/.github/dependabot.yml
+		deleted file mode 100644
+		index 72e0f35..0000000
+		--- a/.github/dependabot.yml
+		+++ /dev/null
+
+		--------------------------------------------------
+		diff --git a/.github/dependabot.yml b/.github/dependabot.yml
+		index 72e0f35..8f2b7dc 100644
+		--- a/.github/dependabot.yml
+		+++ b/.github/dependabot.yml
+
+		--------------------------------------------------
+		diff --git a/.github/dependabot.yml b/.github/dependabot.yml
+		old mode 100644
+		new mode 100755
+		index 72e0f35..8f2b7dc
+		--- a/.github/dependabot.yml
+		+++ b/.github/dependabot.yml
+	*/
+
+	var sbGitHashCtx strings.Builder
+	var gitname, infile1, infile1sha1, infile1mode, infile2, infile2sha2, infile2mode string = args[0], args[1], args[2], args[3], args[4], args[5], args[6]
+	sbGitHashCtx.WriteString(fmt.Sprintf("dyff --git a/%s b/%s\n", gitname, gitname))
+	if infile1 == os.DevNull {
+		sbGitHashCtx.WriteString(fmt.Sprintf("new file mode %s\n", infile2mode))
+		// caculate git object hash of the file
+		infile1sha1 = "0000000"
+	} else if infile2 == os.DevNull {
+		sbGitHashCtx.WriteString(fmt.Sprintf("deleted file mode %s\n", infile1mode))
+		infile2sha2 = "0000000"
+	} else if infile1mode != infile2mode {
+		sbGitHashCtx.WriteString(fmt.Sprintf("old mode %s\n", infile1mode))
+		sbGitHashCtx.WriteString(fmt.Sprintf("new mode %s\n", infile2mode))
+	}
+
+	// file renamed ? Add rename info passed from git diff
+	if len(args) >= 9 {
+		sbGitHashCtx.WriteString(args[8])
+		// renamed and no changes
+		if strings.Contains(args[8], "similarity index 100") {
+			return sbGitHashCtx.String()
+		}
+	} else {
+		sbGitHashCtx.WriteString(fmt.Sprintf("index %s..%s\n", formatGitSHA1(infile1sha1), formatGitSHA1(infile2sha2)))
+	}
+
+	if infile1 == os.DevNull {
+		sbGitHashCtx.WriteString("--- /dev/null\n")
+	} else {
+		sbGitHashCtx.WriteString(fmt.Sprintf("--- a/%s\n", gitname))
+	}
+	if infile2 == os.DevNull {
+		sbGitHashCtx.WriteString("+++ /dev/null\n")
+	} else if len(args) >= 9 { // file renamed
+		sbGitHashCtx.WriteString(fmt.Sprintf("+++ b/%s\n", args[7]))
+	} else {
+		sbGitHashCtx.WriteString(fmt.Sprintf("+++ b/%s\n", gitname))
+	}
+	return sbGitHashCtx.String()
+}
+
+func formatGitSHA1(gitSHA1 string) string {
+	if len(gitSHA1) > GIT_SHA1_LENGTH {
+		return gitSHA1[:GIT_SHA1_LENGTH]
+	}
+	return "0000000"
+}

internal/cmd/root.go

@@ -23,11 +23,11 @@ package cmd
 import (
 	"os"
 	"path/filepath"
-	"strings"
 
 	"github.com/gonvenience/bunt"
 	"github.com/gonvenience/term"
 	"github.com/gonvenience/ytbx"
+	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 )
 
@@ -78,27 +78,33 @@ func ResetSettings() {
 // Execute adds all child commands to the root command and sets flags appropriately.
 // This is called by main.main(). It only needs to happen once to the rootCmd.
 func Execute() error {
-	// In case `KUBECTL_EXTERNAL_DIFF` is set with `dyff`, it is very likely
-	// that `kubectl` intends to use `dyff` for its `diff` command. Therefore,
-	// enable Kubernetes specific entity detection and fix the order issue.
-	if strings.Contains(os.Getenv("KUBECTL_EXTERNAL_DIFF"), name) {
+	// Run with `--kubectl-external-diff` explicitly to trigger argument reordering.
+	// Example when running:
+	// KUBECTL_EXTERNAL_DIFF="dyff between --kubectl-external-diff" kubectl diff -f xxx/yyy/zzz.yaml
+	// kubectl will invoke dyff with the arguments: (injecting two directores as arg[1] and arg[2])
+	// dyff tmp/fileA tmp/fileB between --kubectl-external-diff
+
+	if indexSlice(os.Args, "--kubectl-external-diff") > 1 && indexSlice(os.Args, "between") > 1 {
+		ytbx.PreserveKeyOrderInJSON = true
 		// Rearrange the arguments to match `dyff between --flags from to` to
 		// mitigate an issue in `kubectl`, which puts the `from` and `to` at
 		// the second and third position in the command arguments.
-		var paths, args []string
-		for _, entry := range os.Args {
-			if info, err := os.Stat(entry); err == nil && info.IsDir() {
-				paths = append(paths, entry)
 
+		// only check arg[1] and arg[2], in case `dyff` or `between` are directories
+		for i := 1; i <= 2; i++ {
+			if info, err := os.Stat(os.Args[i]); err == nil && info.IsDir() {
 			} else {
-				args = append(args, entry)
+				return ExitCode{
+					Value: 255,
+					Cause: errors.Errorf("%s is not a directory? is this invoked by kubectl diff?", os.Args[i]),
+				}
 			}
 		}
-
-		os.Args = append(args, paths...)
-
-		// Enable Kubernetes specific entity detection implicitly
-		reportOptions.kubernetesEntityDetection = true
+		var args []string
+		args = append(args, os.Args[0])
+		args = append(args, os.Args[3:]...)
+		args = append(args, os.Args[1], os.Args[2])
+		os.Args = args
 	}
 
 	if err := rootCmd.Execute(); err != nil {
@@ -128,3 +134,12 @@ func init() {
 	rootCmd.PersistentFlags().IntVarP(&term.FixedTerminalWidth, "fixed-width", "w", -1, "disable terminal width detection and use provided fixed value")
 	rootCmd.PersistentFlags().BoolVarP(&ytbx.PreserveKeyOrderInJSON, "preserve-key-order-in-json", "k", false, "use ordered keys during JSON decoding (non standard behavior)")
 }
+
+func indexSlice(s []string, str string) int {
+	for i, v := range s {
+		if v == str {
+			return i
+		}
+	}
+	return -1
+}