Recover from panic gracefully (#2353)

## Changes
This PR adds a recovery function for panics. This indicates to all users
running into a panic that it's a bug and they should report it to
Databricks.

## Tests
Manually and acceptance test.

Before:
```
.venv➜  cli git:(panic-r) ✗ ./cli selftest panic                                                
panic: the databricks selftest panic command always panics

goroutine 1 [running]:
github.com/databricks/cli/cmd/selftest.New.newPanic.func1(0x1400016f208?, {0x1016ca925?, 0x4?, 0x1016ca929?})
        /Users/shreyas.goenka/cli2/cli/cmd/selftest/panic.go:9 +0x2c
github.com/spf13/cobra.(*Command).execute(0x1400016f208, {0x10279bc40, 0x0, 0x0})
        /Users/shreyas.goenka/cli2/cli/vendor/github.com/spf13/cobra/command.go:989 +0x81c
github.com/spf13/cobra.(*Command).ExecuteC(0x14000428908)
        /Users/shreyas.goenka/cli2/cli/vendor/github.com/spf13/cobra/command.go:1117 +0x344
github.com/spf13/cobra.(*Command).ExecuteContextC(...)
        /Users/shreyas.goenka/cli2/cli/vendor/github.com/spf13/cobra/command.go:1050
github.com/databricks/cli/cmd/root.Execute({0x101d60440?, 0x10279bc40?}, 0x10266dd78?)
        /Users/shreyas.goenka/cli2/cli/cmd/root/root.go:101 +0x58
main.main()
        /Users/shreyas.goenka/cli2/cli/main.go:13 +0x44
```

After:
```
.venv➜  cli git:(panic-r) ./cli selftest panic
The Databricks CLI unexpectedly had a fatal error.
Please report this issue to Databricks in the form of a GitHub issue at:
https://github.com/databricks/cli

CLI Version: 0.0.0-dev+aae7ced52d36

Panic Payload: the databricks selftest panic command always panics

Stack Trace:
goroutine 1 [running]:
runtime/debug.Stack()
        /Users/shreyas.goenka/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.23.4.darwin-arm64/src/runtime/debug/stack.go:26 +0x64
github.com/databricks/cli/cmd/root.Execute.func1()
        /Users/shreyas.goenka/cli2/cli/cmd/root/root.go:110 +0xa4
panic({0x10368b5e0?, 0x1039d6d70?})
        /Users/shreyas.goenka/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.23.4.darwin-arm64/src/runtime/panic.go:785 +0x124
github.com/databricks/cli/cmd/selftest.New.newPanic.func1(0x14000145208?, {0x103356be5?, 0x4?, 0x103356be9?})
        /Users/shreyas.goenka/cli2/cli/cmd/selftest/panic.go:9 +0x2c
github.com/spf13/cobra.(*Command).execute(0x14000145208, {0x104427c40, 0x0, 0x0})
        /Users/shreyas.goenka/cli2/cli/vendor/github.com/spf13/cobra/command.go:989 +0x81c
github.com/spf13/cobra.(*Command).ExecuteC(0x14000400c08)
        /Users/shreyas.goenka/cli2/cli/vendor/github.com/spf13/cobra/command.go:1117 +0x344
github.com/spf13/cobra.(*Command).ExecuteContextC(...)
        /Users/shreyas.goenka/cli2/cli/vendor/github.com/spf13/cobra/command.go:1050
github.com/databricks/cli/cmd/root.Execute({0x1039ec440?, 0x104427c40?}, 0x14000400c08)
        /Users/shreyas.goenka/cli2/cli/cmd/root/root.go:128 +0x94
main.main()
        /Users/shreyas.goenka/cli2/cli/main.go:13 +0x44
```

acceptance/panic/output.txt

@@ -0,0 +1,15 @@
+
+>>> [CLI] selftest panic
+The Databricks CLI unexpectedly had a fatal error.
+Please report this issue to Databricks in the form of a GitHub issue at:
+https://github.com/databricks/cli
+
+CLI Version: [DEV_VERSION]
+
+Panic Payload: the databricks selftest panic command always panics
+
+Stack Trace:
+goroutine 1 [running]:
+runtime/debug.Stack()
+
+Exit code: 1

acceptance/panic/script

@@ -0,0 +1,5 @@
+# We filter anything after runtime/debug.Stack() in the output because the stack
+# trace itself is hard to perform replacements on, since it can depend upon the
+# exact setup of where the modules are installed in your Go setup, memory addresses
+# at runtime etc.
+trace $CLI selftest panic 2>&1 | sed '/runtime\/debug\.Stack()/q'

cmd/cmd.go

@@ -12,6 +12,7 @@ import (
 	"github.com/databricks/cli/cmd/fs"
 	"github.com/databricks/cli/cmd/labs"
 	"github.com/databricks/cli/cmd/root"
+	"github.com/databricks/cli/cmd/selftest"
 	"github.com/databricks/cli/cmd/sync"
 	"github.com/databricks/cli/cmd/version"
 	"github.com/databricks/cli/cmd/workspace"
@@ -74,6 +75,7 @@ func New(ctx context.Context) *cobra.Command {
 	cli.AddCommand(labs.New(ctx))
 	cli.AddCommand(sync.New())
 	cli.AddCommand(version.New())
+	cli.AddCommand(selftest.New())
 
 	return cli
 }

cmd/root/root.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"log/slog"
 	"os"
+	"runtime/debug"
 	"strings"
 
 	"github.com/databricks/cli/internal/build"
@@ -96,11 +97,35 @@ func flagErrorFunc(c *cobra.Command, err error) error {
 
 // Execute adds all child commands to the root command and sets flags appropriately.
 // This is called by main.main(). It only needs to happen once to the rootCmd.
-func Execute(ctx context.Context, cmd *cobra.Command) error {
+func Execute(ctx context.Context, cmd *cobra.Command) (err error) {
-	// TODO: deferred panic recovery
+	defer func() {
+		r := recover()
+
+		// No panic. Return normally.
+		if r == nil {
+			return
+		}
+
+		version := build.GetInfo().Version
+		trace := debug.Stack()
+
+		// Set the error so that the CLI exits with a non-zero exit code.
+		err = fmt.Errorf("panic: %v", r)
+
+		fmt.Fprintf(cmd.ErrOrStderr(), `The Databricks CLI unexpectedly had a fatal error.
+Please report this issue to Databricks in the form of a GitHub issue at:
+https://github.com/databricks/cli
+
+CLI Version: %s
+
+Panic Payload: %v
+
+Stack Trace:
+%s`, version, r, string(trace))
+	}()
 
 	// Run the command
-	cmd, err := cmd.ExecuteContextC(ctx)
+	cmd, err = cmd.ExecuteContextC(ctx)
 	if err != nil && !errors.Is(err, ErrAlreadyPrinted) {
 		// If cmdio logger initialization succeeds, then this function logs with the
 		// initialized cmdio logger, otherwise with the default cmdio logger

cmd/selftest/panic.go

@@ -0,0 +1,12 @@
+package selftest
+
+import "github.com/spf13/cobra"
+
+func newPanic() *cobra.Command {
+	return &cobra.Command{
+		Use: "panic",
+		Run: func(cmd *cobra.Command, args []string) {
+			panic("the databricks selftest panic command always panics")
+		},
+	}
+}

cmd/selftest/selftest.go

@@ -0,0 +1,16 @@
+package selftest
+
+import (
+	"github.com/spf13/cobra"
+)
+
+func New() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:    "selftest",
+		Short:  "Non functional CLI commands that are useful for testing",
+		Hidden: true,
+	}
+
+	cmd.AddCommand(newPanic())
+	return cmd
+}