Add deadcode CI check and remove unreachable functions (#4974)

## Why

The CLI is not meant as a library and as such any function not reachable
from `main()` is dead code. The existing `unused` linter skips exported
functions by default (it assumes external consumers might use them),
leaving a gap. `deadcode` from `golang.org/x/tools` does whole-program
reachability analysis and catches these.

## Changes

Added `deadcode` as a CI check via `make checks`. A Python wrapper
script (`tools/check_deadcode.py`) runs `deadcode -test ./...` and
supports two suppression mechanisms:

1. **Directory exclusions** for directories where everything is a false
positive (e.g. `libs/gorules/`, which contains lint rule definitions
loaded by golangci-lint's ruleguard engine, not through Go's call
graph).
2. **Inline comments** (`//deadcode:allow <reason>`) above a function,
matching the `//nolint:` pattern. The wrapper walks backward from the
reported func line, stopping at a blank line, so the allow comment is
found whether it sits immediately above the function or above a
doc-comment block.

The wrapper is needed because raw `deadcode` has no suppression
mechanism. It reports every unreachable function with no way to exclude
known false positives (code loaded via reflection, plugin systems, or
code generators). Without the wrapper, the only options would be to
either accept noisy output that developers learn to ignore, or not run
the check at all. The wrapper keeps the check strict (zero tolerance, CI
fails on any finding) while giving developers two escape hatches for
legitimate exceptions.

Both mechanisms are documented in the script itself.

Removed 40 dead functions across 23 files found in the initial run.
Preserved `DisabledTestNoDuplicatedAnnotations` with `//deadcode:allow`
since the `Disabled` prefix was a deliberate "park for later" marker
from the original author.

## Test plan

- [x] `make deadcode` passes clean ("No dead code found.")
- [x] `make checks` passes (includes deadcode)
- [x] `make lintfull` passes (0 issues, no unused imports)
- [x] `go build ./...` passes
- [x] Unit tests pass for all affected packages

This pull request was AI-assisted by Isaac.

Author: simonfaltum

Makefile

@@ -65,9 +65,13 @@ wsfix:
 links:
 	./tools/update_github_links.py
 
+.PHONY: deadcode
+deadcode:
+	./tools/check_deadcode.py
+
 # Checks other than 'fmt' and 'lint'; these are fast, so can be run first
 .PHONY: checks
-checks: tidy ws links
+checks: tidy ws links deadcode
 
 
 .PHONY: install-pythons

bundle/internal/schema/main_test.go

@@ -125,6 +125,7 @@ func getAnnotations(path string) (annotation.File, error) {
 	return data, err
 }
 
+//deadcode:allow disabled pending annotation system overhaul; preserved intentionally
 func DisabledTestNoDuplicatedAnnotations(t *testing.T) {
 	// Check for duplicated annotations in annotation files
 	files := []string{

bundle/libraries/upload.go

@@ -30,13 +30,6 @@ func Upload(libs map[string][]LocationToUpdate) bundle.Mutator {
 	}
 }
 
-func UploadWithClient(libs map[string][]LocationToUpdate, client filer.Filer) bundle.Mutator {
-	return &upload{
-		libs:   libs,
-		client: client,
-	}
-}
-
 type upload struct {
 	client filer.Filer
 	libs   map[string][]LocationToUpdate

cmd/bundle/utils/utils.go

@@ -4,10 +4,6 @@ import (
 	"context"
 
 	"github.com/databricks/cli/bundle"
-	bundleenv "github.com/databricks/cli/bundle/env"
-	"github.com/databricks/cli/bundle/phases"
-	"github.com/databricks/cli/libs/diag"
-	"github.com/databricks/cli/libs/env"
 	"github.com/databricks/cli/libs/logdiag"
 	"github.com/spf13/cobra"
 )
@@ -20,85 +16,3 @@ func configureVariables(cmd *cobra.Command, b *bundle.Bundle, variables []string
 		}
 	})
 }
-
-// getTargetFromCmd returns the target name from command flags or environment.
-func getTargetFromCmd(cmd *cobra.Command) string {
-	// Check command line flag first
-	if flag := cmd.Flag("target"); flag != nil {
-		if value := flag.Value.String(); value != "" {
-			return value
-		}
-	}
-
-	// Check deprecated environment flag
-	if flag := cmd.Flag("environment"); flag != nil {
-		if value := flag.Value.String(); value != "" {
-			return value
-		}
-	}
-
-	// Fall back to environment variable
-	target, _ := bundleenv.Target(cmd.Context())
-	return target
-}
-
-// ReloadBundle reloads the bundle configuration without modifying the command context.
-// This is useful when you need to refresh the bundle configuration after changes
-// without side effects like setting values on the context.
-func ReloadBundle(cmd *cobra.Command) *bundle.Bundle {
-	ctx := cmd.Context()
-
-	// Load the bundle configuration fresh from the filesystem
-	b := bundle.MustLoad(ctx)
-	if b == nil || logdiag.HasError(ctx) {
-		return b
-	}
-
-	// Load the target configuration
-	if target := getTargetFromCmd(cmd); target == "" {
-		phases.LoadDefaultTarget(ctx, b)
-	} else {
-		phases.LoadNamedTarget(ctx, b, target)
-	}
-
-	if logdiag.HasError(ctx) {
-		return b
-	}
-
-	// Configure the workspace profile if provided
-	configureProfile(cmd, b)
-
-	// Configure variables if provided
-	variables, err := cmd.Flags().GetStringSlice("var")
-	if err != nil {
-		logdiag.LogDiag(ctx, diag.FromErr(err)[0])
-		return b
-	}
-	configureVariables(cmd, b, variables)
-	return b
-}
-
-// configureProfile applies the profile flag to the bundle.
-func configureProfile(cmd *cobra.Command, b *bundle.Bundle) {
-	profile := getProfileFromCmd(cmd)
-	if profile == "" {
-		return
-	}
-
-	bundle.ApplyFuncContext(cmd.Context(), b, func(ctx context.Context, b *bundle.Bundle) {
-		b.Config.Workspace.Profile = profile
-	})
-}
-
-// getProfileFromCmd returns the profile from command flags or environment.
-func getProfileFromCmd(cmd *cobra.Command) string {
-	// Check command line flag first
-	if flag := cmd.Flag("profile"); flag != nil {
-		if value := flag.Value.String(); value != "" {
-			return value
-		}
-	}
-
-	// Fall back to environment variable
-	return env.Get(cmd.Context(), "DATABRICKS_CONFIG_PROFILE")
-}

experimental/aitools/lib/installer/installer.go

@@ -67,14 +67,6 @@ type InstallOptions struct {
 	Scope               string   // ScopeGlobal or ScopeProject (default: global)
 }
 
-// FetchManifest fetches the skills manifest from the skills repo.
-// This is a convenience wrapper that uses the default GitHubManifestSource.
-func FetchManifest(ctx context.Context) (*Manifest, error) {
-	src := &GitHubManifestSource{}
-	ref := GetSkillsRef(ctx)
-	return src.FetchManifest(ctx, ref)
-}
-
 func fetchSkillFile(ctx context.Context, ref, skillName, filePath string) ([]byte, error) {
 	url := fmt.Sprintf("https://raw.githubusercontent.com/%s/%s/%s/%s/%s/%s",
 		skillsRepoOwner, skillsRepoName, ref, skillsRepoPath, skillName, filePath)
@@ -303,19 +295,6 @@ func InstallAllSkills(ctx context.Context) error {
 	return InstallSkillsForAgents(ctx, src, installed, InstallOptions{})
 }
 
-// InstallSkill installs a single skill by name for all detected agents.
-func InstallSkill(ctx context.Context, skillName string) error {
-	installed := agents.DetectInstalled(ctx)
-	if len(installed) == 0 {
-		printNoAgentsDetected(ctx)
-		return nil
-	}
-
-	PrintInstallingFor(ctx, installed)
-	src := &GitHubManifestSource{}
-	return InstallSkillsForAgents(ctx, src, installed, InstallOptions{SpecificSkills: []string{skillName}})
-}
-
 // PrintInstallingFor prints the "Installing..." header with agent names.
 func PrintInstallingFor(ctx context.Context, targetAgents []*agents.Agent) {
 	names := make([]string, len(targetAgents))

experimental/ssh/internal/keys/secrets.go

@@ -67,17 +67,3 @@ func putSecret(ctx context.Context, client *databricks.WorkspaceClient, scope, k
 	}
 	return nil
 }
-
-// PutSecretInScope creates the secret scope if needed and stores the secret.
-// sessionID is the unique identifier for the session (cluster ID for dedicated clusters, connection name for serverless).
-func PutSecretInScope(ctx context.Context, client *databricks.WorkspaceClient, sessionID, key, value string) (string, error) {
-	scopeName, err := CreateKeysSecretScope(ctx, client, sessionID)
-	if err != nil {
-		return "", err
-	}
-	err = putSecret(ctx, client, scopeName, key, value)
-	if err != nil {
-		return "", err
-	}
-	return scopeName, nil
-}

internal/testcli/golden.go

@@ -25,7 +25,3 @@ func RandomName(prefix ...string) string {
 	sb.WriteString(strings.ReplaceAll(uuid.New().String(), "-", ""))
 	return sb.String()
 }
-
-func ReplaceWindowsLineEndings(s string) string {
-	return strings.ReplaceAll(s, "\r\n", "\n")
-}

internal/testutil/helpers.go

@@ -88,28 +88,6 @@ func ListSecretKeys(ctx context.Context, scope string) ([]ListItem, error) {
 	return out, nil
 }
 
-// ListSQLWarehousesItems returns SQL warehouses as ListItems (reuses same API as ListSQLWarehouses).
-func ListSQLWarehousesItems(ctx context.Context) ([]ListItem, error) {
-	w, err := workspaceClient(ctx)
-	if err != nil {
-		return nil, err
-	}
-	iter := w.Warehouses.List(ctx, sql.ListWarehousesRequest{})
-	whs, err := listing.ToSlice(ctx, iter)
-	if err != nil {
-		return nil, err
-	}
-	out := make([]ListItem, 0, min(len(whs), maxListResults))
-	for _, wh := range whs {
-		label := wh.Name
-		if wh.State != "" {
-			label = fmt.Sprintf("%s (%s)", wh.Name, wh.State)
-		}
-		out = append(out, ListItem{ID: wh.Id, Label: label})
-	}
-	return capResults(out), nil
-}
-
 // ListSchemas returns UC schemas within a catalog as selectable items.
 func ListSchemas(ctx context.Context, catalogName string) ([]ListItem, error) {
 	w, err := workspaceClient(ctx)

libs/apps/prompt/listers.go

@@ -467,20 +467,6 @@ func promptForPagedResource(ctx context.Context, r manifest.Resource, required b
 	return singleValueResult(r, value), nil
 }
 
-// PromptForWarehouse shows a picker to select a SQL warehouse.
-func PromptForWarehouse(ctx context.Context) (string, error) {
-	var items []ListItem
-	err := RunWithSpinnerCtx(ctx, "Fetching SQL warehouses...", func() error {
-		var fetchErr error
-		items, fetchErr = ListSQLWarehousesItems(ctx)
-		return fetchErr
-	})
-	if err != nil {
-		return "", fmt.Errorf("failed to fetch SQL warehouses: %w", err)
-	}
-	return PromptFromList(ctx, "Select SQL Warehouse", "no SQL warehouses found. Create one in your workspace first", items, true)
-}
-
 // resourceTitle returns a prompt title for a resource, including the plugin name
 // for context when available (e.g. "Select SQL Warehouse for Analytics").
 func resourceTitle(fallback string, r manifest.Resource) string {