From 94340f7074fc8d14f08b09e3dfbff19ec51c0e4a Mon Sep 17 00:00:00 2001
From: Anirudh Oppiliappan <anirudh@tangled.org>
Date: Wed, 28 Jan 2026 14:48:36 +0200
Subject: [PATCH] knotserver/{git,xrpc}: last commit for specific file path

RepoBlob now also includes the last commit for the blob.

Signed-off-by: Anirudh Oppiliappan <anirudh@tangled.org>
---
 knotserver/git/last_commit.go | 36 +++++++++++++++++++++++++++++++++++
 knotserver/xrpc/repo_blob.go  | 25 ++++++++++++++++++++++++
 2 files changed, 61 insertions(+)

diff --git a/knotserver/git/last_commit.go b/knotserver/git/last_commit.go
index 1de21228..fd722689 100644
--- a/knotserver/git/last_commit.go
+++ b/knotserver/git/last_commit.go
@@ -14,6 +14,7 @@ import (
 	"github.com/dgraph-io/ristretto"
 	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/object"
+	"tangled.org/core/types"
 )
 
 var (
@@ -185,3 +186,38 @@ func ancestors(p string) []string {
 	}
 	return ancestors
 }
+
+// GetLastCommitForPath returns the last commit information for a specific file path
+func (g *GitRepo) GetLastCommitForPath(ctx context.Context, filePath string) (*types.LastCommitInfo, error) {
+	c, err := g.r.CommitObject(g.h)
+	if err != nil {
+		return nil, fmt.Errorf("commit object: %w", err)
+	}
+
+	tree, err := c.Tree()
+	if err != nil {
+		return nil, fmt.Errorf("file tree: %w", err)
+	}
+
+	// parent directory for calculateCommitTime
+	parent := path.Dir(filePath)
+	if parent == "." {
+		parent = ""
+	}
+
+	times, err := g.calculateCommitTimeIn(ctx, tree, parent, 2*time.Second)
+	if err != nil {
+		return nil, fmt.Errorf("calculate commit time: %w", err)
+	}
+
+	commitInfo, ok := times[filePath]
+	if !ok {
+		return nil, fmt.Errorf("no commit found for path: %s", filePath)
+	}
+
+	return &types.LastCommitInfo{
+		Hash:    commitInfo.hash,
+		Message: commitInfo.message,
+		When:    commitInfo.when,
+	}, nil
+}
diff --git a/knotserver/xrpc/repo_blob.go b/knotserver/xrpc/repo_blob.go
index 3d038683..3c07b736 100644
--- a/knotserver/xrpc/repo_blob.go
+++ b/knotserver/xrpc/repo_blob.go
@@ -1,6 +1,7 @@
 package xrpc
 
 import (
+	"context"
 	"crypto/sha256"
 	"encoding/base64"
 	"fmt"
@@ -8,6 +9,7 @@ import (
 	"path/filepath"
 	"slices"
 	"strings"
+	"time"
 
 	"tangled.org/core/api/tangled"
 	"tangled.org/core/knotserver/git"
@@ -142,6 +144,29 @@ func (x *Xrpc) RepoBlob(w http.ResponseWriter, r *http.Request) {
 		response.MimeType = &mimeType
 	}
 
+	ctx, cancel := context.WithTimeout(r.Context(), 2*time.Second)
+	defer cancel()
+
+	lastCommit, err := gr.GetLastCommitForPath(ctx, treePath)
+	if err == nil && lastCommit != nil {
+		shortHash := lastCommit.Hash.String()[:8]
+		response.LastCommit = &tangled.RepoBlob_LastCommit{
+			Hash:      lastCommit.Hash.String(),
+			ShortHash: &shortHash,
+			Message:   lastCommit.Message,
+			When:      lastCommit.When.Format(time.RFC3339),
+		}
+
+		// try to get author information
+		commit, err := gr.Commit(lastCommit.Hash)
+		if err == nil {
+			response.LastCommit.Author = &tangled.RepoBlob_Signature{
+				Name:  commit.Author.Name,
+				Email: commit.Author.Email,
+			}
+		}
+	}
+
 	writeJson(w, response)
 }
 
-- 
2.51.2