fix(cli): show ready sync start dependencies (#25546)

## Problem

Follow-on to:

- https://github.com/coder/coder/pull/25089

`coder exp sync start` still printed a generic success message when the
unit was ready on the first status check. That hid whether the unit had
no dependencies or had dependencies that were already satisfied before
`sync start` ran.

Before:

```text
Success
```

## Solution
Print explicit startup output for both ready-at-first-check cases.

After, dependencies already satisfied:

```text
Unit "test-unit" started immediately, dependencies already satisfied: [dep-unit, dep-unit-2]
```

After, no dependencies:

```text
Unit "test-unit" started with no dependencies
```

The existing waiting path is unchanged and still reports the
dependencies while waiting and after waiting finishes.

Co-authored-by: Sas Swart <sas.swart.cdk@gmail.com>

cli/sync_start.go

@@ -57,15 +57,19 @@ func (*RootCmd) syncStart(socketPath *string) *serpent.Command {
 			}
 			ready := statusResp.IsReady
 
-			var waitedFor []string
-			if !ready {
+			var allDependencies []string
+			var unsatisfiedDependencies []string
 			for _, dep := range statusResp.Dependencies {
+				allDependencies = append(allDependencies, string(dep.DependsOn))
 				if !dep.IsSatisfied {
-						waitedFor = append(waitedFor, string(dep.DependsOn))
+					unsatisfiedDependencies = append(unsatisfiedDependencies, string(dep.DependsOn))
 				}
 			}
-				slices.Sort(waitedFor)
-				waitedForList := strings.Join(waitedFor, ", ")
+			slices.Sort(allDependencies)
+			slices.Sort(unsatisfiedDependencies)
+
+			if !ready {
+				waitedForList := strings.Join(unsatisfiedDependencies, ", ")
 
 				cliui.Infof(i.Stdout, "Unit %q is waiting for dependencies to be satisfied: [%s]", unitName, waitedForList)
 
@@ -96,10 +100,13 @@ func (*RootCmd) syncStart(socketPath *string) *serpent.Command {
 				return xerrors.Errorf("start unit failed: %w", err)
 			}
 
-			if len(waitedFor) == 0 {
-				cliui.Info(i.Stdout, "Success")
-			} else {
-				cliui.Info(i.Stdout, fmt.Sprintf("Unit %q finished waiting for dependencies: [%s]", unitName, strings.Join(waitedFor, ", ")))
+			switch {
+			case len(allDependencies) == 0:
+				cliui.Info(i.Stdout, fmt.Sprintf("Unit %q started with no dependencies", unitName))
+			case len(unsatisfiedDependencies) == 0:
+				cliui.Info(i.Stdout, fmt.Sprintf("Unit %q started immediately, dependencies already satisfied: [%s]", unitName, strings.Join(allDependencies, ", ")))
+			default:
+				cliui.Info(i.Stdout, fmt.Sprintf("Unit %q finished waiting for dependencies: [%s]", unitName, strings.Join(unsatisfiedDependencies, ", ")))
 			}
 
 			return nil

cli/sync_test.go

@@ -158,6 +158,42 @@ func TestSyncCommands_Golden(t *testing.T) {
 		clitest.TestGoldenFile(t, "TestSyncCommands_Golden/start_with_dependencies", outBuf.Bytes(), nil)
 	})
 
+	t.Run("start_with_satisfied_dependencies", func(t *testing.T) {
+		t.Parallel()
+		path, cleanup := setupSocketServer(t)
+		defer cleanup()
+
+		ctx := testutil.Context(t, testutil.WaitShort)
+
+		// Set up dependencies: test-unit depends on dep-unit and dep-unit-2.
+		client, err := agentsocket.NewClient(ctx, agentsocket.WithPath(path))
+		require.NoError(t, err)
+
+		err = client.SyncWant(ctx, "test-unit", "dep-unit")
+		require.NoError(t, err)
+		err = client.SyncWant(ctx, "test-unit", "dep-unit-2")
+		require.NoError(t, err)
+		err = client.SyncStart(ctx, "dep-unit")
+		require.NoError(t, err)
+		err = client.SyncComplete(ctx, "dep-unit")
+		require.NoError(t, err)
+		err = client.SyncStart(ctx, "dep-unit-2")
+		require.NoError(t, err)
+		err = client.SyncComplete(ctx, "dep-unit-2")
+		require.NoError(t, err)
+		client.Close()
+
+		var outBuf bytes.Buffer
+		inv, _ := clitest.New(t, "exp", "sync", "start", "test-unit", "--socket-path", path)
+		inv.Stdout = &outBuf
+		inv.Stderr = &outBuf
+
+		err = inv.WithContext(ctx).Run()
+		require.NoError(t, err)
+
+		clitest.TestGoldenFile(t, "TestSyncCommands_Golden/start_with_satisfied_dependencies", outBuf.Bytes(), nil)
+	})
+
 	t.Run("want", func(t *testing.T) {
 		t.Parallel()
 		path, cleanup := setupSocketServer(t)

cli/testdata/TestSyncCommands_Golden/start_no_dependencies.golden

@@ -1 +1 @@
-Success
+Unit "test-unit" started with no dependencies

cli/testdata/TestSyncCommands_Golden/start_with_satisfied_dependencies.golden

@@ -0,0 +1 @@
+Unit "test-unit" started immediately, dependencies already satisfied: [dep-unit, dep-unit-2]