Merge pull request cli#12655 from yuvrajangadsingh/feature/pr-diff-exclude

feat(pr diff): add --exclude flag to filter files from diff output

Author: babakks

pkg/cmd/pr/diff/diff.go

@@ -2,10 +2,12 @@ package diff
 
 import (
 	"bufio"
+	"bytes"
 	"errors"
 	"fmt"
 	"io"
 	"net/http"
+	"path"
 	"regexp"
 	"strings"
 	"unicode"
@@ -36,6 +38,7 @@ type DiffOptions struct {
 	Patch       bool
 	NameOnly    bool
 	BrowserMode bool
+	Exclude     []string
 }
 
 func NewCmdDiff(f *cmdutil.Factory, runF func(*DiffOptions) error) *cobra.Command {
@@ -57,7 +60,24 @@ func NewCmdDiff(f *cmdutil.Factory, runF func(*DiffOptions) error) *cobra.Comman
 			is selected.
 
 			With %[1]s--web%[1]s flag, open the pull request diff in a web browser instead.
+
+			Use %[1]s--exclude%[1]s to filter out files matching a glob pattern. The pattern
+			uses forward slashes as path separators on all platforms. You can repeat
+			the flag to exclude multiple patterns.
 		`, "`"),
+		Example: heredoc.Doc(`
+			# See diff for current branch
+			$ gh pr diff
+
+			# See diff for a specific PR
+			$ gh pr diff 123
+
+			# Exclude files from diff output
+			$ gh pr diff --exclude '*.yml' --exclude 'generated/*'
+
+			# Exclude matching files by name
+			$ gh pr diff --name-only --exclude '*.generated.*'
+		`),
 		Args: cobra.MaximumNArgs(1),
 		RunE: func(cmd *cobra.Command, args []string) error {
 			opts.Finder = shared.NewFinder(f)
@@ -92,6 +112,7 @@ func NewCmdDiff(f *cmdutil.Factory, runF func(*DiffOptions) error) *cobra.Comman
 	cmd.Flags().BoolVar(&opts.Patch, "patch", false, "Display diff in patch format")
 	cmd.Flags().BoolVar(&opts.NameOnly, "name-only", false, "Display only names of changed files")
 	cmd.Flags().BoolVarP(&opts.BrowserMode, "web", "w", false, "Open the pull request diff in the browser")
+	cmd.Flags().StringSliceVarP(&opts.Exclude, "exclude", "e", nil, "Exclude files matching glob `patterns` from the diff")
 
 	return cmd
 }
@@ -135,6 +156,13 @@ func diffRun(opts *DiffOptions) error {
 	defer diffReadCloser.Close()
 
 	var diff io.Reader = diffReadCloser
+	if len(opts.Exclude) > 0 {
+		filtered, err := filterDiff(diff, opts.Exclude)
+		if err != nil {
+			return err
+		}
+		diff = filtered
+	}
 	if opts.IO.IsStdoutTTY() {
 		diff = sanitizedReader(diff)
 	}
@@ -292,8 +320,7 @@ func changedFilesNames(w io.Writer, r io.Reader) error {
 	// `"`` + hello-\360\237\230\200-world"
 	//
 	// Where I'm using the `` to indicate a string to avoid confusion with the " character.
-	pattern := regexp.MustCompile(`(?:^|\n)diff\s--git.*\s(["]?)b/(.*)`)
-	matches := pattern.FindAllStringSubmatch(string(diff), -1)
+	matches := diffHeaderRegexp.FindAllStringSubmatch(string(diff), -1)
 
 	for _, val := range matches {
 		name := strings.TrimSpace(val[1] + val[2])
@@ -357,3 +384,67 @@ func (t sanitizer) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err e
 func isPrint(r rune) bool {
 	return r == '\n' || r == '\r' || r == '\t' || unicode.IsPrint(r)
 }
+
+var diffHeaderRegexp = regexp.MustCompile(`(?:^|\n)diff\s--git.*\s("?)b/(.*)`)
+
+// filterDiff reads a unified diff and returns a new reader with file entries
+// matching any of the exclude patterns removed.
+func filterDiff(r io.Reader, excludePatterns []string) (io.Reader, error) {
+	data, err := io.ReadAll(r)
+	if err != nil {
+		return nil, err
+	}
+
+	var result bytes.Buffer
+	for _, section := range splitDiffSections(string(data)) {
+		name := extractFileName(section)
+		if name != "" && matchesAny(name, excludePatterns) {
+			continue
+		}
+		result.WriteString(section)
+	}
+	return &result, nil
+}
+
+// splitDiffSections splits a unified diff string into per-file sections.
+// Each section starts with "diff --git" and includes all content up to (but
+// not including) the next "diff --git" line.
+func splitDiffSections(diff string) []string {
+	marker := "\ndiff --git "
+	parts := strings.Split(diff, marker)
+	if len(parts) == 1 {
+		return []string{diff}
+	}
+	sections := make([]string, 0, len(parts))
+	for i, p := range parts {
+		if i == 0 {
+			if len(p) > 0 {
+				sections = append(sections, p+"\n")
+			}
+		} else {
+			sections = append(sections, "diff --git "+p)
+		}
+	}
+	return sections
+}
+
+func extractFileName(section string) string {
+	m := diffHeaderRegexp.FindStringSubmatch(section)
+	if m == nil {
+		return ""
+	}
+	return strings.TrimSpace(m[1] + m[2])
+}
+
+func matchesAny(name string, excludePatterns []string) bool {
+	for _, p := range excludePatterns {
+		if matched, _ := path.Match(p, name); matched {
+			return true
+		}
+		// Also match against the basename so "*.yml" matches "dir/file.yml"
+		if matched, _ := path.Match(p, path.Base(name)); matched {
+			return true
+		}
+	}
+	return false
+}

pkg/cmd/pr/diff/diff_test.go

@@ -87,6 +87,26 @@ func Test_NewCmdDiff(t *testing.T) {
 			isTTY:   true,
 			wantErr: "argument required when using the `--repo` flag",
 		},
+		{
+			name:  "exclude single pattern",
+			args:  "--exclude '*.yml'",
+			isTTY: true,
+			want: DiffOptions{
+				SelectorArg: "",
+				UseColor:    true,
+				Exclude:     []string{"*.yml"},
+			},
+		},
+		{
+			name:  "exclude multiple patterns",
+			args:  "--exclude '*.yml' --exclude Makefile",
+			isTTY: true,
+			want: DiffOptions{
+				SelectorArg: "",
+				UseColor:    true,
+				Exclude:     []string{"*.yml", "Makefile"},
+			},
+		},
 		{
 			name:    "invalid --color argument",
 			args:    "--color doublerainbow",
@@ -142,6 +162,7 @@ func Test_NewCmdDiff(t *testing.T) {
 			assert.Equal(t, tt.want.SelectorArg, opts.SelectorArg)
 			assert.Equal(t, tt.want.UseColor, opts.UseColor)
 			assert.Equal(t, tt.want.BrowserMode, opts.BrowserMode)
+			assert.Equal(t, tt.want.Exclude, opts.Exclude)
 		})
 	}
 }
@@ -211,6 +232,48 @@ func Test_diffRun(t *testing.T) {
 				stubDiffRequest(reg, "application/vnd.github.v3.diff", fmt.Sprintf(testDiff, "", "", "", ""))
 			},
 		},
+		{
+			name: "exclude yml files",
+			opts: DiffOptions{
+				SelectorArg: "123",
+				UseColor:    false,
+				Exclude:     []string{"*.yml"},
+			},
+			wantFields: []string{"number"},
+			wantStdout: `diff --git a/Makefile b/Makefile
+index f2b4805c..3d7bd0f9 100644
+--- a/Makefile
++++ b/Makefile
+@@ -22,8 +22,8 @@ test:
+ 	go test ./...
+ .PHONY: test
+
+-site:
+-	git clone https://github.com/github/cli.github.com.git "$@"
++site: bin/gh
++	bin/gh repo clone github/cli.github.com "$@"
+
+ site-docs: site
+ 	git -C site pull
+`,
+			httpStubs: func(reg *httpmock.Registry) {
+				stubDiffRequest(reg, "application/vnd.github.v3.diff", fmt.Sprintf(testDiff, "", "", "", ""))
+			},
+		},
+		{
+			name: "name only with exclude",
+			opts: DiffOptions{
+				SelectorArg: "123",
+				UseColor:    false,
+				NameOnly:    true,
+				Exclude:     []string{"*.yml"},
+			},
+			wantFields: []string{"number"},
+			wantStdout: "Makefile\n",
+			httpStubs: func(reg *httpmock.Registry) {
+				stubDiffRequest(reg, "application/vnd.github.v3.diff", fmt.Sprintf(testDiff, "", "", "", ""))
+			},
+		},
 		{
 			name: "web mode",
 			opts: DiffOptions{
@@ -394,6 +457,116 @@ func stubDiffRequest(reg *httpmock.Registry, accept, diff string) {
 		})
 }
 
+func Test_filterDiff(t *testing.T) {
+	rawDiff := fmt.Sprintf(testDiff, "", "", "", "")
+
+	tests := []struct {
+		name     string
+		patterns []string
+		want     string
+	}{
+		{
+			name:     "exclude yml files",
+			patterns: []string{"*.yml"},
+			want: `diff --git a/Makefile b/Makefile
+index f2b4805c..3d7bd0f9 100644
+--- a/Makefile
++++ b/Makefile
+@@ -22,8 +22,8 @@ test:
+ 	go test ./...
+ .PHONY: test
+
+-site:
+-	git clone https://github.com/github/cli.github.com.git "$@"
++site: bin/gh
++	bin/gh repo clone github/cli.github.com "$@"
+
+ site-docs: site
+ 	git -C site pull
+`,
+		},
+		{
+			name:     "exclude Makefile",
+			patterns: []string{"Makefile"},
+			want: `diff --git a/.github/workflows/releases.yml b/.github/workflows/releases.yml
+index 73974448..b7fc0154 100644
+--- a/.github/workflows/releases.yml
++++ b/.github/workflows/releases.yml
+@@ -44,6 +44,11 @@ jobs:
+           token: ${{secrets.SITE_GITHUB_TOKEN}}
+       - name: Publish documentation site
+         if: "!contains(github.ref, '-')" # skip prereleases
++        env:
++          GIT_COMMITTER_NAME: cli automation
++          GIT_AUTHOR_NAME: cli automation
++          GIT_COMMITTER_EMAIL: noreply@github.com
++          GIT_AUTHOR_EMAIL: noreply@github.com
+         run: make site-publish
+       - name: Move project cards
+         if: "!contains(github.ref, '-')" # skip prereleases
+`,
+		},
+		{
+			name:     "exclude all files",
+			patterns: []string{"*.yml", "Makefile"},
+			want:     "",
+		},
+		{
+			name:     "no matches",
+			patterns: []string{"*.go"},
+			want:     rawDiff,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			reader, err := filterDiff(strings.NewReader(rawDiff), tt.patterns)
+			require.NoError(t, err)
+			got, err := io.ReadAll(reader)
+			require.NoError(t, err)
+			assert.Equal(t, tt.want, string(got))
+		})
+	}
+}
+
+func Test_matchesAny(t *testing.T) {
+	tests := []struct {
+		name     string
+		filename string
+		patterns []string
+		want     bool
+	}{
+		{
+			name:     "exact match",
+			filename: "Makefile",
+			patterns: []string{"Makefile"},
+			want:     true,
+		},
+		{
+			name:     "glob extension",
+			filename: ".github/workflows/releases.yml",
+			patterns: []string{"*.yml"},
+			want:     true,
+		},
+		{
+			name:     "no match",
+			filename: "main.go",
+			patterns: []string{"*.yml"},
+			want:     false,
+		},
+		{
+			name:     "directory glob",
+			filename: ".github/workflows/releases.yml",
+			patterns: []string{".github/*/*"},
+			want:     true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.want, matchesAny(tt.filename, tt.patterns))
+		})
+	}
+}
+
 func Test_sanitizedReader(t *testing.T) {
 	input := strings.NewReader("\t hello \x1B[m world! ăѣ𝔠ծề\r\n")
 	expected := "\t hello \\u{1b}[m world! ăѣ𝔠ծề\r\n"