errcheck issues fixed (#28646)

Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>

server/.golangci.yml

@@ -87,7 +87,6 @@ issues:
         channels/api4/system_local.go|\
         channels/api4/team_local.go|\
         channels/api4/team_test.go|\
-        channels/api4/user.go|\
         channels/api4/user_test.go|\
         channels/api4/webhook_test.go|\
         channels/app/admin.go|\

server/channels/api4/user.go

@@ -374,7 +374,9 @@ func getDefaultProfileImage(c *Context, w http.ResponseWriter, r *http.Request)
 
 	w.Header().Set("Cache-Control", fmt.Sprintf("max-age=%v, private", model.DayInSeconds)) // 24 hrs
 	w.Header().Set("Content-Type", "image/png")
-	w.Write(img)
+	if _, err := w.Write(img); err != nil {
+		c.Logger.Warn("Error while writing response", mlog.Err(err))
+	}
 }
 
 func getProfileImage(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -419,11 +421,17 @@ func getProfileImage(c *Context, w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.Header().Set("Content-Type", "image/png")
-	w.Write(img)
+	if _, err := w.Write(img); err != nil {
+		c.Logger.Warn("Error while writing response", mlog.Err(err))
+	}
 }
 
 func setProfileImage(c *Context, w http.ResponseWriter, r *http.Request) {
-	defer io.Copy(io.Discard, r.Body)
+	defer func() {
+		if _, err := io.Copy(io.Discard, r.Body); err != nil {
+			c.Logger.Warn("Error discarding request body", mlog.Err(err))
+		}
+	}()
 
 	c.RequireUserId()
 	if c.Err != nil {
@@ -932,7 +940,9 @@ func getUsers(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	w.Write(js)
+	if _, err := w.Write(js); err != nil {
+		c.Logger.Warn("Error while writing response", mlog.Err(err))
+	}
 }
 
 func getUsersByIds(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -979,7 +989,9 @@ func getUsersByIds(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	w.Write(js)
+	if _, err := w.Write(js); err != nil {
+		c.Logger.Warn("Error while writing response", mlog.Err(err))
+	}
 }
 
 func getUsersByNames(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -1010,7 +1022,9 @@ func getUsersByNames(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	w.Write(js)
+	if _, err := w.Write(js); err != nil {
+		c.Logger.Warn("Error while writing response", mlog.Err(err))
+	}
 }
 
 func getKnownUsers(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -1125,7 +1139,9 @@ func searchUsers(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	w.Write(js)
+	if _, err := w.Write(js); err != nil {
+		c.Logger.Warn("Error while writing response", mlog.Err(err))
+	}
 }
 
 func autocompleteUsers(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -2016,7 +2032,9 @@ func loginCWS(c *Context, w http.ResponseWriter, r *http.Request) {
 		c.Err = model.NewAppError("loginCWS", "api.user.login_cws.license.error", nil, "", http.StatusUnauthorized)
 		return
 	}
-	r.ParseForm()
+	if err := r.ParseForm(); err != nil {
+		c.Logger.Warn("Failed to parse form data", mlog.Err(err))
+	}
 	var loginID string
 	var token string
 	var campaign string
@@ -2120,7 +2138,9 @@ func getSessions(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	w.Write(js)
+	if _, err := w.Write(js); err != nil {
+		c.Logger.Warn("Error while writing response", mlog.Err(err))
+	}
 }
 
 func revokeSession(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -2440,7 +2460,9 @@ func switchAccountType(c *Context, w http.ResponseWriter, r *http.Request) {
 	auditRec.Success()
 	c.LogAudit("success")
 
-	w.Write([]byte(model.MapToJSON(map[string]string{"follow_link": link})))
+	if _, err := w.Write([]byte(model.MapToJSON(map[string]string{"follow_link": link}))); err != nil {
+		c.Logger.Warn("Error while writing response", mlog.Err(err))
+	}
 }
 
 func createUserAccessToken(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -2548,7 +2570,9 @@ func searchUserAccessTokens(c *Context, w http.ResponseWriter, r *http.Request)
 		return
 	}
 
-	w.Write(js)
+	if _, err := w.Write(js); err != nil {
+		c.Logger.Warn("Error while writing response", mlog.Err(err))
+	}
 }
 
 func getUserAccessTokens(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -2569,7 +2593,9 @@ func getUserAccessTokens(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	w.Write(js)
+	if _, err := w.Write(js); err != nil {
+		c.Logger.Warn("Error while writing response", mlog.Err(err))
+	}
 }
 
 func getUserAccessTokensForUser(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -2600,7 +2626,9 @@ func getUserAccessTokensForUser(c *Context, w http.ResponseWriter, r *http.Reque
 		return
 	}
 
-	w.Write(js)
+	if _, err := w.Write(js); err != nil {
+		c.Logger.Warn("Error while writing response", mlog.Err(err))
+	}
 }
 
 func getUserAccessToken(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -3016,7 +3044,9 @@ func convertUserToBot(c *Context, w http.ResponseWriter, r *http.Request) {
 
 	auditRec.Success()
 
-	w.Write(js)
+	if _, err := w.Write(js); err != nil {
+		c.Logger.Warn("Error while writing response", mlog.Err(err))
+	}
 }
 
 func getUploadsForUser(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -3041,7 +3071,9 @@ func getUploadsForUser(c *Context, w http.ResponseWriter, r *http.Request) {
 		c.Err = model.NewAppError("getUploadsForUser", "api.marshal_error", nil, "", http.StatusInternalServerError).Wrap(err)
 		return
 	}
-	w.Write(js)
+	if _, err := w.Write(js); err != nil {
+		c.Logger.Warn("Error while writing response", mlog.Err(err))
+	}
 }
 
 func getChannelMembersForUser(c *Context, w http.ResponseWriter, r *http.Request) {