ssh: always re-upload dev builds of the tunnel binary

experimental/ssh/CLAUDE.md

@@ -34,19 +34,11 @@ Confirm the archive carries your change before uploading, e.g.:
 unzip -p ./dist/databricks_cli_linux_amd64.zip databricks | strings | grep <a-string-your-change-adds>
 ```
 
-**RULE: Dev/snapshot uploads are skipped when the versioned workspace directory already exists.**
-`uploadReleases` (`internal/client/releases.go`) skips the upload when the binary
-is already present at the versioned workspace path. Dev builds keep the same
-version string (`0.0.0-dev+<commit>`) across rebuilds, so a rebuilt server binary
-is silently **not** re-uploaded and the cluster runs the stale one. Before
-re-verifying a rebuilt binary, delete the versioned directory and connect with a
-fresh `--name`:
-
-```sh
-VER=$(./cli version | grep -o '0.0.0-dev+[a-f0-9]*')
-databricks workspace delete --recursive \
-  "/Workspace/Users/<you>/.databricks/ssh-tunnel/$VER"
-```
+**RULE: Start a fresh server after rebuilding.** `uploadReleases`
+(`internal/client/releases.go`) always re-uploads dev and snapshot builds, but
+`connect` reuses a server that is already running for the same version, and that
+server still runs the previous binary. Connect with a fresh `--name` on serverless,
+or a fresh cluster on dedicated.
 
 ## Server vs. session
 

experimental/ssh/internal/client/releases.go

@@ -16,6 +16,7 @@ import (
 	"time"
 
 	"github.com/databricks/cli/experimental/ssh/internal/workspace"
+	"github.com/databricks/cli/internal/build"
 	"github.com/databricks/cli/libs/filer"
 	"github.com/databricks/cli/libs/log"
 	"github.com/databricks/databricks-sdk-go"
@@ -108,12 +109,16 @@ func uploadReleases(ctx context.Context, workspaceFiler filer.Filer, getRelease
 		remoteBinaryPath := filepath.ToSlash(filepath.Join(remoteSubFolder, "databricks"))
 		remoteArchivePath := filepath.ToSlash(filepath.Join(remoteSubFolder, "databricks.zip"))
 
-		_, err := workspaceFiler.Stat(ctx, remoteBinaryPath)
-		if err == nil {
-			log.Infof(ctx, "File %s already exists in the workspace, skipping upload", remoteBinaryPath)
-			continue
-		} else if !errors.Is(err, fs.ErrNotExist) {
-			return fmt.Errorf("failed to check if file %s exists in workspace: %w", remoteBinaryPath, err)
+		if build.IsDevelopmentVersion(version) {
+			log.Infof(ctx, "Development version %s, overwriting %s in the workspace", version, remoteBinaryPath)
+		} else {
+			_, err := workspaceFiler.Stat(ctx, remoteBinaryPath)
+			if err == nil {
+				log.Infof(ctx, "File %s already exists in the workspace, skipping upload", remoteBinaryPath)
+				continue
+			} else if !errors.Is(err, fs.ErrNotExist) {
+				return fmt.Errorf("failed to check if file %s exists in workspace: %w", remoteBinaryPath, err)
+			}
 		}
 
 		releaseReader, err := getRelease(ctx, arch, version, releasesDir)

experimental/ssh/internal/client/releases_test.go

@@ -1,12 +1,16 @@
 package client
 
 import (
+	"context"
 	"errors"
 	"fmt"
+	"io"
 	"net/http"
+	"strings"
 	"syscall"
 	"testing"
 
+	"github.com/databricks/cli/libs/filer"
 	"github.com/databricks/databricks-sdk-go/apierr"
 	"github.com/databricks/databricks-sdk-go/config"
 	"github.com/stretchr/testify/assert"
@@ -95,3 +99,45 @@ func TestNewHTTP11WorkspaceClient(t *testing.T) {
 	// The source config is not mutated: it keeps its own (nil) transport.
 	assert.Nil(t, src.HTTPTransport)
 }
+
+func TestUploadReleasesWithExistingBinary(t *testing.T) {
+	tests := []struct {
+		name         string
+		version      string
+		wantUploaded []string
+	}{
+		{
+			name:         "release version skips the upload",
+			version:      "1.12.0",
+			wantUploaded: nil,
+		},
+		{
+			name:         "dev version overwrites the binary",
+			version:      "1.12.1-dev+abcdef123456",
+			wantUploaded: []string{"amd64", "arm64"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ctx := t.Context()
+			workspaceFiler, err := filer.NewLocalClient(t.TempDir())
+			require.NoError(t, err)
+			for _, arch := range []string{"amd64", "arm64"} {
+				remoteBinaryPath := strings.TrimSuffix(getReleaseName(arch, tt.version), ".zip") + "/databricks"
+				err := workspaceFiler.Write(ctx, remoteBinaryPath, strings.NewReader("old"), filer.CreateParentDirectories)
+				require.NoError(t, err)
+			}
+
+			var uploaded []string
+			getRelease := func(ctx context.Context, architecture, version, releasesDir string) (io.ReadCloser, error) {
+				uploaded = append(uploaded, architecture)
+				return io.NopCloser(strings.NewReader("new")), nil
+			}
+
+			err = uploadReleases(ctx, workspaceFiler, getRelease, tt.version, "")
+			require.NoError(t, err)
+			assert.Equal(t, tt.wantUploaded, uploaded)
+		})
+	}
+}