fix: simplify RunRemote to not re-prefix source or dest

RunRemote was adding user@host: prefixes on top of the paths already
pre-prefixed by engine.go in the remote-to-remote branch, causing
"both remote" rsync errors. The source path was also incorrectly
prefixed with srcUserHost:, making rsync reject the command entirely.

The fix: buildArgs already orders args correctly for rsync (source
then dest), so just use args[-2] and args[-1] as-is without any
additional prefixing.

Makefile

@@ -1,5 +1,5 @@
 BINARY=syncserver
-VERSION?=1.0.38
+VERSION?=1.0.39
 GO?=go
 LDFLAGS=-s -w -X main.version=$(VERSION) -X main.commit=$(shell git rev-parse --short HEAD 2>/dev/null || echo unknown)
 BUILD_FLAGS=CGO_ENABLED=0

internal/syncengine/rsync_runner.go

@@ -96,39 +96,16 @@ func (r *RsyncRunner) RunRemote(ctx context.Context, pair *SyncPairConfig, src *
 		destKey = filepath.Join(r.sshDir, "id_ed25519")
 	}
 
-	srcUserHost := fmt.Sprintf("%s@%s", src.SSHUser, src.Host)
 	args := r.buildArgs(pair)
 
 	innerSSH := fmt.Sprintf("ssh -i %s -o StrictHostKeyChecking=accept-new -o UserKnownHostsFile=%s",
 		destKey, filepath.Join(r.sshDir, "known_hosts"))
 	rsyncFlags := strings.Join(args[:len(args)-2], " ")
-
+	sourcePath := args[len(args)-2]
-	var sourcePath, destPath string
+	destPath := args[len(args)-1]
-	if pair.Direction == "pull" {
-		sourcePath = args[len(args)-1]
-		destPath = args[len(args)-2]
-	} else {
-		sourcePath = args[len(args)-2]
-		destPath = args[len(args)-1]
-	}
-
-	var remoteSrc, remoteDst string
-	if pair.Direction == "pull" {
-		remoteSrc = sourcePath
-		remoteDst = destPath
-		if !strings.Contains(destPath, "@") {
-			remoteDst = fmt.Sprintf("%s@%s:%s", dst.SSHUser, dst.Host, destPath)
-		}
-	} else {
-		remoteDst = destPath
-		if !strings.Contains(destPath, "@") {
-			remoteDst = fmt.Sprintf("%s@%s:%s", dst.SSHUser, dst.Host, destPath)
-		}
-		remoteSrc = fmt.Sprintf("%s:%s", srcUserHost, sourcePath)
-	}
 
 	remoteCmd := fmt.Sprintf("rsync %s -e %q %s %s",
-		rsyncFlags, innerSSH, remoteSrc, remoteDst)
+		rsyncFlags, innerSSH, sourcePath, destPath)
 
 	sshArgs := []string{
 		"-i", src.PrivKey,

internal/syncengine/rsync_runner_test.go

@@ -16,40 +16,15 @@ type remoteCmdTest struct {
 }
 
 func (tc remoteCmdTest) build() (srcArg, dstArg string) {
-	srcUserHost := tc.srcUser + "@" + tc.srcHost
-	dstUserHost := tc.dstUser + "@" + tc.dstHost
-
 	runner := NewRsyncRunner("/tmp/ssh", "")
 	args := runner.buildArgs(&SyncPairConfig{
 		Source:    tc.srcPath,
 		Dest:      tc.dstPath,
 		Direction: tc.direction,
 	})
-
+	sourcePath := args[len(args)-2]
-	var sourcePath, destPath string
+	destPath := args[len(args)-1]
-	if tc.direction == "pull" {
+	return sourcePath, destPath
-		sourcePath = args[len(args)-1]
-		destPath = args[len(args)-2]
-	} else {
-		sourcePath = args[len(args)-2]
-		destPath = args[len(args)-1]
-	}
-
-	var remoteSrc, remoteDst string
-	if tc.direction == "pull" {
-		remoteSrc = sourcePath
-		remoteDst = destPath
-		if !strings.Contains(destPath, "@") {
-			remoteDst = dstUserHost + ":" + destPath
-		}
-	} else {
-		remoteDst = destPath
-		if !strings.Contains(destPath, "@") {
-			remoteDst = dstUserHost + ":" + destPath
-		}
-		remoteSrc = srcUserHost + ":" + sourcePath
-	}
-	return remoteSrc, remoteDst
 }
 
 func TestBuildArgs_Push(t *testing.T) {
@@ -175,7 +150,7 @@ func TestRunRemote_PushDestNoDoublePrefix(t *testing.T) {
 	}
 }
 
-func TestRunRemote_PushSrcCorrectlyPrefixed(t *testing.T) {
+func TestRunRemote_PushSrcAndDestStayAsIs(t *testing.T) {
 	tc := remoteCmdTest{
 		srcHost:   "10.5.1.10",
 		srcUser:   "root",
@@ -187,15 +162,15 @@ func TestRunRemote_PushSrcCorrectlyPrefixed(t *testing.T) {
 	}
 	srcArg, dstArg := tc.build()
 
-	if !strings.HasPrefix(srcArg, "root@10.5.1.10:/") {
+	if srcArg != "/share/homes/admin/media" {
-		t.Errorf("push src = %q, want prefix 'root@10.5.1.10:/'", srcArg)
+		t.Errorf("push src = %q, want raw path '/share/homes/admin/media' (no user@host: prefix added)", srcArg)
 	}
-	if !strings.HasPrefix(dstArg, "admin@10.5.0.144:/") {
+	if dstArg != "/share/media/peliculas" {
-		t.Errorf("push dst = %q, want prefix 'admin@10.5.0.144:/'", dstArg)
+		t.Errorf("push dst = %q, want raw path '/share/media/peliculas'", dstArg)
 	}
 }
 
-func TestRunRemote_PullSrcNotPrefixed(t *testing.T) {
+func TestRunRemote_PullSrcAndDestStayAsIs(t *testing.T) {
 	tc := remoteCmdTest{
 		srcHost:   "10.5.0.144",
 		srcUser:   "admin",
@@ -205,13 +180,16 @@ func TestRunRemote_PullSrcNotPrefixed(t *testing.T) {
 		dstPath:   "/share/data",
 		direction: "pull",
 	}
-	srcArg, _ := tc.build()
+	srcArg, dstArg := tc.build()
 
 	if countOccurrences(srcArg, "@") > 1 {
 		t.Errorf("pull src %q has double SSH spec", srcArg)
 	}
-	if srcArg != "admin@10.5.0.144:/share/media/peliculas" {
+	if srcArg != "/share/data" {
-		t.Errorf("pull src = %q, want 'admin@10.5.0.144:/share/media/peliculas'", srcArg)
+		t.Errorf("pull src (rsync dest) = %q, want raw '/share/data'", srcArg)
+	}
+	if !strings.HasPrefix(dstArg, "admin@10.5.0.144:/") {
+		t.Errorf("pull dst (rsync src) = %q, want 'admin@10.5.0.144:/...' prefix", dstArg)
 	}
 }