attempt to find PatchId

patchset.Make.go

@@ -1,9 +1,11 @@
 package forgepb
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"strings"
 	"time"
@@ -83,40 +85,6 @@ func (f *Forge) MakeDevelPatchSet(name string) (*Patchset, error) {
 	return pset, nil
 }
 
-/*
-func (f *Forge) MakeMasterPatchSet() (*Patchset, error) {
-	pset := newPatchset("masterBranchPS")
-	dir, err := os.MkdirTemp("", "forge")
-	if err != nil {
-		return nil, err
-	}
-	defer os.RemoveAll(dir) // clean up
-	pset.TmpDir = dir
-
-	all := f.Repos.SortByFullPath()
-	for all.Scan() {
-		repo := all.Next()
-		startb := repo.GetMasterBranchName()
-		endb := repo.GetUserBranchName()
-
-		if startb == "" {
-			continue
-		}
-		if endb == "" {
-			continue
-		}
-		// log.Info("repo", repo.GetGoPath(), startb, "..", endb)
-		pset.StartBranchName = startb
-		pset.EndBranchName = endb
-		err := pset.makePatchSetNew(repo)
-		if err != nil {
-			return nil, err
-		}
-	}
-	return pset, nil
-}
-*/
-
 func (pset *Patchset) makePatchSetNew(repo *gitpb.Repo) error {
 	startBranch := pset.StartBranchName
 	endBranch := pset.EndBranchName
@@ -163,6 +131,8 @@ func (pset *Patchset) makePatchSetNew(repo *gitpb.Repo) error {
 	return err
 }
 
+// git show <original_commit_hash> | git patch-id
+// git cat-file -p <commit_hash> | grep tree
 // process each file in pDir/
 func (p *Patchset) addPatchFiles(repo *gitpb.Repo) error {
 	psetDir := repo.GetGoPath()
@@ -181,10 +151,6 @@ func (p *Patchset) addPatchFiles(repo *gitpb.Repo) error {
 		if info.IsDir() {
 			return nil
 		}
-		// log.Info("IS THIS A FULL PATH ?", path)
-		// log.Info("trim this from path ?", fullDir)
-		// log.Info("trim this from path ?", psetDir)
-		// log.Info("trim this from path ?", tmpDir)
 		data, err := os.ReadFile(path)
 		if err != nil {
 			log.Info("addPatchFile() failed", path)
@@ -194,7 +160,12 @@ func (p *Patchset) addPatchFiles(repo *gitpb.Repo) error {
 		patch := new(Patch)
 		patch.Filename, _ = filepath.Rel(p.TmpDir, path)
 		patch.Data = data
-		patch.parseData()
+		if err := patch.parseData(); err != nil {
+			return err
+		}
+		if err := findPatchId(repo, patch); err != nil {
+			return err
+		}
 		patch.StartHash = repo.ActualDevelHash()
 		patch.NewHash = "na"
 		patch.Namespace = repo.GetGoPath()
@@ -212,7 +183,7 @@ func (p *Patchset) addPatchFiles(repo *gitpb.Repo) error {
 // looks at the git format-patch output
 // saves the commit Hash
 // saves the diff lines
-func (p *Patch) parseData() string {
+func (p *Patch) parseData() error {
 	lines := strings.Split(string(p.Data), "\n")
 	for _, line := range lines {
 		fields := strings.Fields(line)
@@ -228,7 +199,7 @@ func (p *Patch) parseData() string {
 			p.Files = append(p.Files, line)
 		}
 	}
-	return ""
+	return nil
 }
 
 // just an example of how to walk only directories
@@ -253,3 +224,58 @@ func onlyWalkDirs(pDir string) error {
 	})
 	return baderr
 }
+
+// func runPipe() error {
+func findPatchId(repo *gitpb.Repo, p *Patch) error {
+	if p.CommitHash == "" {
+		return log.Errorf("%s commit hash not found", p.Filename)
+	}
+
+	// 1. Create the command to get the diff for the commit.
+	//    "git show" is the perfect tool for this.
+	cmdShow := exec.Command("git", "show", p.CommitHash)
+	cmdShow.Dir = repo.GetFullPath()
+
+	// 2. Create the command to calculate the patch-id from stdin.
+	cmdPipeID := exec.Command("git", "patch-id", "--stable")
+	cmdPipeID.Dir = repo.GetFullPath()
+
+	// 3. Connect the output of "git show" to the input of "git patch-id".
+	//    This is the Go equivalent of the shell pipe `|`.
+	pipe, err := cmdShow.StdoutPipe()
+	if err != nil {
+		return fmt.Errorf("failed to create pipe: %w", err)
+	}
+	cmdPipeID.Stdin = pipe
+
+	// 4. We need a buffer to capture the final output from git patch-id.
+	var output bytes.Buffer
+	cmdPipeID.Stdout = &output
+
+	// 5. Start the reading command (patch-id) first.
+	if err := cmdPipeID.Start(); err != nil {
+		return fmt.Errorf("failed to start git-patch-id: %w", err)
+	}
+
+	// 6. Run the writing command (show). This will block until it's done.
+	if err := cmdShow.Run(); err != nil {
+		return fmt.Errorf("failed to run git-show: %w", err)
+	}
+
+	// 7. Wait for the reading command to finish.
+	if err := cmdPipeID.Wait(); err != nil {
+		return fmt.Errorf("failed to wait for git-patch-id: %w", err)
+	}
+
+	fields := strings.Fields(output.String())
+	if len(fields) != 2 {
+		return fmt.Errorf("git-patch-id produced empty output")
+	}
+
+	if fields[0] != p.CommitHash {
+		return fmt.Errorf("patchid did not match %s != %v", p.CommitHash, fields)
+	}
+
+	p.PatchId = fields[1]
+	return nil
+}