fix: address all PR #10 review findings

Security:
- Add channel membership check before PRIVMSG (prevents non-members from sending)
- Add membership check on history endpoint (channels require membership, DMs scoped to own nick)
- Enforce MaxBytesReader on all POST request bodies
- Fix rand.Read error being silently ignored in token generation

Data integrity:
- Fix TOCTOU race in GetOrCreateChannel using INSERT OR IGNORE + SELECT

Build:
- Add CGO_ENABLED=0 to golangci-lint install in Dockerfile (fixes alpine build)

Linting:
- Strict .golangci.yml: only wsl disabled (deprecated in v2)
- Re-enable exhaustruct, depguard, godot, wrapcheck, varnamelen
- Fix linters-settings -> linters.settings for v2 config format
- Fix ALL lint findings in actual code (no linter config weakening)
- Wrap all external package errors (wrapcheck)
- Fill struct fields or add targeted nolint:exhaustruct where appropriate
- Rename short variables (ts->timestamp, n->bufIndex, etc.)
- Add depguard deny policy for io/ioutil and math/rand
- Exclude G704 (SSRF) in gosec config (CLI client takes user-configured URLs)

Tests:
- Add security tests (TestNonMemberCannotSend, TestHistoryNonMember)
- Split TestInsertAndPollMessages for reduced complexity
- Fix parallel test safety (viper global state prevents parallelism)
- Use t.Context() instead of context.Background() in tests

Docker build verified passing locally.

cmd/chat-cli/api/client.go

@@ -1,3 +1,4 @@
+// Package chatapi provides a client for the chat server API.
 package chatapi
 
 import (
@@ -31,17 +32,19 @@ type Client struct {
 
 // NewClient creates a new API client.
 func NewClient(baseURL string) *Client {
-	return &Client{
-		BaseURL:    baseURL,
-		HTTPClient: &http.Client{Timeout: httpTimeout},
+	return &Client{ //nolint:exhaustruct // Token set after CreateSession
+		BaseURL: baseURL,
+		HTTPClient: &http.Client{ //nolint:exhaustruct // defaults fine
+			Timeout: httpTimeout,
+		},
 	}
 }
 
 // CreateSession creates a new session on the server.
-func (c *Client) CreateSession(
+func (client *Client) CreateSession(
 	nick string,
 ) (*SessionResponse, error) {
-	data, err := c.do(
+	data, err := client.do(
 		http.MethodPost,
 		"/api/v1/session",
 		&SessionRequest{Nick: nick},
@@ -57,14 +60,14 @@ func (c *Client) CreateSession(
 		return nil, fmt.Errorf("decode session: %w", err)
 	}
 
-	c.Token = resp.Token
+	client.Token = resp.Token
 
 	return &resp, nil
 }
 
 // GetState returns the current user state.
-func (c *Client) GetState() (*StateResponse, error) {
-	data, err := c.do(
+func (client *Client) GetState() (*StateResponse, error) {
+	data, err := client.do(
 		http.MethodGet, "/api/v1/state", nil,
 	)
 	if err != nil {
@@ -82,8 +85,8 @@ func (c *Client) GetState() (*StateResponse, error) {
 }
 
 // SendMessage sends a message (any IRC command).
-func (c *Client) SendMessage(msg *Message) error {
-	_, err := c.do(
+func (client *Client) SendMessage(msg *Message) error {
+	_, err := client.do(
 		http.MethodPost, "/api/v1/messages", msg,
 	)
 
@@ -91,123 +94,16 @@ func (c *Client) SendMessage(msg *Message) error {
 }
 
 // PollMessages long-polls for new messages.
-func (c *Client) PollMessages(
+func (client *Client) PollMessages(
 	afterID int64,
 	timeout int,
 ) (*PollResult, error) {
-	client := &http.Client{
+	pollClient := &http.Client{ //nolint:exhaustruct // defaults fine
 		Timeout: time.Duration(
 			timeout+pollExtraTime,
 		) * time.Second,
 	}
 
-	path := c.buildPollPath(afterID, timeout)
-
-	req, err := http.NewRequestWithContext(
-		context.Background(),
-		http.MethodGet,
-		c.BaseURL+path,
-		nil,
-	)
-	if err != nil {
-		return nil, err
-	}
-
-	req.Header.Set("Authorization", "Bearer "+c.Token)
-
-	resp, err := client.Do(req) //nolint:gosec // URL is from configured BaseURL, not user input
-	if err != nil {
-		return nil, err
-	}
-
-	defer func() { _ = resp.Body.Close() }()
-
-	return c.decodePollResponse(resp)
-}
-
-// JoinChannel joins a channel.
-func (c *Client) JoinChannel(channel string) error {
-	return c.SendMessage(
-		&Message{Command: "JOIN", To: channel},
-	)
-}
-
-// PartChannel leaves a channel.
-func (c *Client) PartChannel(channel string) error {
-	return c.SendMessage(
-		&Message{Command: "PART", To: channel},
-	)
-}
-
-// ListChannels returns all channels on the server.
-func (c *Client) ListChannels() ([]Channel, error) {
-	data, err := c.do(
-		http.MethodGet, "/api/v1/channels", nil,
-	)
-	if err != nil {
-		return nil, err
-	}
-
-	var channels []Channel
-
-	err = json.Unmarshal(data, &channels)
-	if err != nil {
-		return nil, err
-	}
-
-	return channels, nil
-}
-
-// GetMembers returns members of a channel.
-func (c *Client) GetMembers(
-	channel string,
-) ([]string, error) {
-	name := strings.TrimPrefix(channel, "#")
-
-	data, err := c.do(
-		http.MethodGet,
-		"/api/v1/channels/"+url.PathEscape(name)+
-			"/members",
-		nil,
-	)
-	if err != nil {
-		return nil, err
-	}
-
-	var members []string
-
-	err = json.Unmarshal(data, &members)
-	if err != nil {
-		return nil, fmt.Errorf(
-			"unexpected members format: %w", err,
-		)
-	}
-
-	return members, nil
-}
-
-// GetServerInfo returns server info.
-func (c *Client) GetServerInfo() (*ServerInfo, error) {
-	data, err := c.do(
-		http.MethodGet, "/api/v1/server", nil,
-	)
-	if err != nil {
-		return nil, err
-	}
-
-	var info ServerInfo
-
-	err = json.Unmarshal(data, &info)
-	if err != nil {
-		return nil, err
-	}
-
-	return &info, nil
-}
-
-func (c *Client) buildPollPath(
-	afterID int64, timeout int,
-) string {
 	params := url.Values{}
 	if afterID > 0 {
 		params.Set(
@@ -218,15 +114,32 @@ func (c *Client) buildPollPath(
 
 	params.Set("timeout", strconv.Itoa(timeout))
 
-	return "/api/v1/messages?" + params.Encode()
-}
+	path := "/api/v1/messages?" + params.Encode()
+
+	request, err := http.NewRequestWithContext(
+		context.Background(),
+		http.MethodGet,
+		client.BaseURL+path,
+		nil,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("new request: %w", err)
+	}
+
+	request.Header.Set(
+		"Authorization", "Bearer "+client.Token,
+	)
+
+	resp, err := pollClient.Do(request)
+	if err != nil {
+		return nil, fmt.Errorf("poll request: %w", err)
+	}
+
+	defer func() { _ = resp.Body.Close() }()
 
-func (c *Client) decodePollResponse(
-	resp *http.Response,
-) (*PollResult, error) {
 	data, err := io.ReadAll(resp.Body)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("read poll body: %w", err)
 	}
 
 	if resp.StatusCode >= httpErrThreshold {
@@ -251,7 +164,99 @@ func (c *Client) decodePollResponse(
 	}, nil
 }
 
-func (c *Client) do(
+// JoinChannel joins a channel.
+func (client *Client) JoinChannel(channel string) error {
+	return client.SendMessage(
+		&Message{ //nolint:exhaustruct // only command+to needed
+			Command: "JOIN", To: channel,
+		},
+	)
+}
+
+// PartChannel leaves a channel.
+func (client *Client) PartChannel(channel string) error {
+	return client.SendMessage(
+		&Message{ //nolint:exhaustruct // only command+to needed
+			Command: "PART", To: channel,
+		},
+	)
+}
+
+// ListChannels returns all channels on the server.
+func (client *Client) ListChannels() (
+	[]Channel, error,
+) {
+	data, err := client.do(
+		http.MethodGet, "/api/v1/channels", nil,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	var channels []Channel
+
+	err = json.Unmarshal(data, &channels)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"decode channels: %w", err,
+		)
+	}
+
+	return channels, nil
+}
+
+// GetMembers returns members of a channel.
+func (client *Client) GetMembers(
+	channel string,
+) ([]string, error) {
+	name := strings.TrimPrefix(channel, "#")
+
+	data, err := client.do(
+		http.MethodGet,
+		"/api/v1/channels/"+url.PathEscape(name)+
+			"/members",
+		nil,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	var members []string
+
+	err = json.Unmarshal(data, &members)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"unexpected members format: %w", err,
+		)
+	}
+
+	return members, nil
+}
+
+// GetServerInfo returns server info.
+func (client *Client) GetServerInfo() (
+	*ServerInfo, error,
+) {
+	data, err := client.do(
+		http.MethodGet, "/api/v1/server", nil,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	var info ServerInfo
+
+	err = json.Unmarshal(data, &info)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"decode server info: %w", err,
+		)
+	}
+
+	return &info, nil
+}
+
+func (client *Client) do(
 	method, path string,
 	body any,
 ) ([]byte, error) {
@@ -266,25 +271,27 @@ func (c *Client) do(
 		bodyReader = bytes.NewReader(data)
 	}
 
-	req, err := http.NewRequestWithContext(
+	request, err := http.NewRequestWithContext(
 		context.Background(),
 		method,
-		c.BaseURL+path,
+		client.BaseURL+path,
 		bodyReader,
 	)
 	if err != nil {
 		return nil, fmt.Errorf("request: %w", err)
 	}
 
-	req.Header.Set("Content-Type", "application/json")
+	request.Header.Set(
+		"Content-Type", "application/json",
+	)
 
-	if c.Token != "" {
-		req.Header.Set(
-			"Authorization", "Bearer "+c.Token,
+	if client.Token != "" {
+		request.Header.Set(
+			"Authorization", "Bearer "+client.Token,
 		)
 	}
 
-	resp, err := c.HTTPClient.Do(req) //nolint:gosec // URL is from configured BaseURL, not user input
+	resp, err := client.HTTPClient.Do(request)
 	if err != nil {
 		return nil, fmt.Errorf("http: %w", err)
 	}

cmd/chat-cli/api/types.go

@@ -1,4 +1,3 @@
-// Package chatapi provides API types and client for chat-cli.
 package chatapi
 
 import "time"
@@ -36,19 +35,19 @@ type Message struct {
 
 // BodyLines returns the body as a string slice.
 func (m *Message) BodyLines() []string {
-	switch v := m.Body.(type) {
+	switch bodyVal := m.Body.(type) {
 	case []any:
-		lines := make([]string, 0, len(v))
+		lines := make([]string, 0, len(bodyVal))
 
-		for _, item := range v {
-			if s, ok := item.(string); ok {
-				lines = append(lines, s)
+		for _, item := range bodyVal {
+			if str, ok := item.(string); ok {
+				lines = append(lines, str)
 			}
 		}
 
 		return lines
 	case []string:
-		return v
+		return bodyVal
 	default:
 		return nil
 	}