Fix race condition on customSearchPath slice closes #4792 (#4837)

* Add test for #4792: customSearchPath data race

This test demonstrates the data race on the customSearchPath slice when
accessed concurrently from multiple goroutines without synchronization.

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Co-Authored-By: Claude <noreply@anthropic.com>

* Fix #4792: Add mutex protection for customSearchPath slice

The customSearchPath slice was being accessed concurrently from multiple
goroutines without synchronization, causing data races. This fix adds a
dedicated mutex (searchPathMutex) to protect all reads and writes to the
customSearchPath and searchPathPrefix fields.

Changes:
- Added searchPathMutex field to DbClient struct
- Initialize searchPathMutex in NewDbClient constructor
- Protected all customSearchPath writes in SetRequiredSessionSearchPath
- Protected all customSearchPath reads in GetRequiredSessionSearchPath
- Protected all customSearchPath reads in GetCustomSearchPath
- Fixed logging in ensureSessionSearchPath to use already-fetched value
- Updated test to initialize searchPathMutex for proper testing

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

---------

Co-authored-by: Claude <noreply@anthropic.com>

pkg/db/db_client/db_client.go

@@ -54,6 +54,8 @@ type DbClient struct {
 	// if a custom search path or a prefix is used, store it here
 	customSearchPath []string
 	searchPathPrefix []string
+	// allows locked access to customSearchPath and searchPathPrefix
+	searchPathMutex *sync.Mutex
 	// the default user search path
 	userSearchPath []string
 	// disable timing - set whilst in process of querying the timing
@@ -71,6 +73,7 @@ func NewDbClient(ctx context.Context, connectionString string, opts ...ClientOpt
 		parallelSessionInitLock: semaphore.NewWeighted(constants.MaxParallelClientInits),
 		sessions:                make(map[uint32]*db_common.DatabaseSession),
 		sessionsMutex:           &sync.Mutex{},
+		searchPathMutex:         &sync.Mutex{},
 		connectionString:        connectionString,
 	}
 

pkg/db/db_client/db_client_search_path.go

@@ -29,9 +29,6 @@ func (c *DbClient) SetRequiredSessionSearchPath(ctx context.Context) error {
 	// default required path to user search path
 	requiredSearchPath := c.userSearchPath
 
-	// store custom search path and search path prefix
-	c.searchPathPrefix = searchPathPrefix
-
 	// if a search path was passed, use that
 	if len(configuredSearchPath) > 0 {
 		requiredSearchPath = configuredSearchPath
@@ -43,6 +40,12 @@ func (c *DbClient) SetRequiredSessionSearchPath(ctx context.Context) error {
 	requiredSearchPath = db_common.EnsureInternalSchemaSuffix(requiredSearchPath)
 
 	// if either configuredSearchPath or searchPathPrefix are set, store requiredSearchPath as customSearchPath
+	c.searchPathMutex.Lock()
+	defer c.searchPathMutex.Unlock()
+
+	// store custom search path and search path prefix
+	c.searchPathPrefix = searchPathPrefix
+
 	if len(configuredSearchPath)+len(searchPathPrefix) > 0 {
 		c.customSearchPath = requiredSearchPath
 	} else {
@@ -75,6 +78,9 @@ func (c *DbClient) loadUserSearchPath(ctx context.Context, connection *pgx.Conn)
 
 // GetRequiredSessionSearchPath implements Client
 func (c *DbClient) GetRequiredSessionSearchPath() []string {
+	c.searchPathMutex.Lock()
+	defer c.searchPathMutex.Unlock()
+
 	if c.customSearchPath != nil {
 		return c.customSearchPath
 	}
@@ -83,6 +89,9 @@ func (c *DbClient) GetRequiredSessionSearchPath() []string {
 }
 
 func (c *DbClient) GetCustomSearchPath() []string {
+	c.searchPathMutex.Lock()
+	defer c.searchPathMutex.Unlock()
+
 	return c.customSearchPath
 }
 
@@ -107,7 +116,7 @@ func (c *DbClient) ensureSessionSearchPath(ctx context.Context, session *db_comm
 	}
 
 	// so we need to set the search path
-	log.Printf("[TRACE] session search path will be updated to  %s", strings.Join(c.customSearchPath, ","))
+	log.Printf("[TRACE] session search path will be updated to  %s", strings.Join(requiredSearchPath, ","))
 
 	err := db_common.ExecuteSystemClientCall(ctx, session.Connection.Conn(), func(ctx context.Context, tx pgx.Tx) error {
 		_, err := tx.Exec(ctx, fmt.Sprintf("set search_path to %s", strings.Join(db_common.PgEscapeSearchPath(requiredSearchPath), ",")))

pkg/db/db_client/db_client_session_test.go

@@ -1,6 +1,7 @@
 package db_client
 
 import (
+	"context"
 	"sync"
 	"testing"
 
@@ -166,3 +167,55 @@ func TestDbClient_SessionConnectionNilSafety(t *testing.T) {
 	// Session is created with nil connection initially
 	assert.Nil(t, session.Connection, "New session should have nil connection initially")
 }
+
+// TestDbClient_SessionSearchPathUpdatesThreadSafe verifies that concurrent access
+// to customSearchPath does not cause data races.
+// Reference: https://github.com/turbot/steampipe/issues/4792
+//
+// This test simulates concurrent goroutines accessing and modifying the customSearchPath
+// slice. Without proper synchronization, this causes a data race.
+//
+// Run with: go test -race -run TestDbClient_SessionSearchPathUpdatesThreadSafe
+func TestDbClient_SessionSearchPathUpdatesThreadSafe(t *testing.T) {
+	// Create a DbClient with the fields we need for testing
+	client := &DbClient{
+		customSearchPath: []string{"public", "internal"},
+		userSearchPath:   []string{"public"},
+		searchPathMutex:  &sync.Mutex{},
+	}
+
+	// Number of concurrent operations to test
+	const numGoroutines = 100
+
+	var wg sync.WaitGroup
+	wg.Add(numGoroutines * 3)
+
+	// Simulate concurrent readers calling GetRequiredSessionSearchPath
+	for i := 0; i < numGoroutines; i++ {
+		go func() {
+			defer wg.Done()
+			_ = client.GetRequiredSessionSearchPath()
+		}()
+	}
+
+	// Simulate concurrent readers calling GetCustomSearchPath
+	for i := 0; i < numGoroutines; i++ {
+		go func() {
+			defer wg.Done()
+			_ = client.GetCustomSearchPath()
+		}()
+	}
+
+	// Simulate concurrent writers calling SetRequiredSessionSearchPath
+	// This is the most dangerous operation as it modifies the slice
+	for i := 0; i < numGoroutines; i++ {
+		go func() {
+			defer wg.Done()
+			ctx := context.Background()
+			// This will write to customSearchPath
+			_ = client.SetRequiredSessionSearchPath(ctx)
+		}()
+	}
+
+	wg.Wait()
+}