Consider to enable nullable annotations for all projects

[realLiangshiwei]

We enabled nullable for the templates
But the ABP framework is not enabled, and developers will mistakenly think that the return value is not null when using some APIs
For example, the cache may return null.

abp/framework/src/Volo.Abp.Caching/Volo/Abp/Caching/IDistributedCache.cs

Lines 26 to 40 in 101afac

	public interface IDistributedCache<TCacheItem, TCacheKey>
	where TCacheItem : class
	{
	/// <summary>
	/// Gets a cache item with the given key. If no cache item is found for the given key then returns null.
	/// </summary>
	/// <param name="key">The key of cached item to be retrieved from the cache.</param>
	/// <param name="hideErrors">Indicates to throw or hide the exceptions for the distributed cache.</param>
	/// <param name="considerUow">This will store the cache in the current unit of work until the end of the current unit of work does not really affect the cache.</param>
	/// <returns>The cache item, or null.</returns>
	TCacheItem Get(
	TCacheKey key,
	bool? hideErrors = null,
	bool considerUow = false
	);

Microsoft enabled nullable for their packages, we might consider doing the same:

• Annotate Microsoft.Extensions.* assemblies for nullable reference types dotnet/runtime#43605
• Update ASP.NET Core to use C# 8's nullable reference types dotnet/aspnetcore#5680

[realLiangshiwei]

ABP Framework

Group1

• Volo.Abp.Core Enable nullable annotations for Volo.Abp.Core #16693
• Volo.Abp.Data
• Volo.Abp.Json
• Volo.Abp.Json.Abstractions
• Volo.Abp.Json.Newtonsoft
• Volo.Abp.Json.SystemTextJson
• Volo.Abp.Threading
• Volo.Abp.Timing
• Volo.Abp.Guids
• Volo.Abp.UI
• Volo.Abp.UI.Navigation
• Volo.Abp.Validation
• Volo.Abp.Validation.Abstractions
• Volo.Abp.Castle.Core
• Volo.Abp.Autofac
• Volo.Abp.Autofac.WebAssembly
• Volo.Abp.Localization
• Volo.Abp.Localization.Abstractions
• Volo.Abp.Security
• Volo.Abp.Uow
• Volo.Abp.ApiVersioning.Abstractions
• Volo.Abp.VirtualFileSystem
• Volo.Abp.Settings
• Volo.Abp.Serialization
• Volo.Abp.Specifications
• Volo.Abp.TestBase
• Volo.Abp.ExceptionHandling
• Volo.Abp.Ldap
• Volo.Abp.Ldap.Abstractions
• Volo.Abp.Minify
• Volo.Abp.RemoteServices
• Volo.Abp.MultiLingualObjects
• Volo.Abp.Sms
• Volo.Abp.Sms.Aliyun
• Volo.Abp.ObjectExtending

Group2 #17047

• Volo.Abp.AspNetCore.Authentication.JwtBearer
• Volo.Abp.AspNetCore.Authentication.OAuth
• Volo.Abp.AspNetCore.Authentication.OpenIdConnect

Group3 #17062

• Volo.Abp.AspNetCore
• Volo.Abp.AspNetCore.Components
• Volo.Abp.AspNetCore.Components.MauiBlazor
• Volo.Abp.AspNetCore.Components.MauiBlazor.Theming
• Volo.Abp.AspNetCore.Components.Server
• Volo.Abp.AspNetCore.Components.Server.Theming
• Volo.Abp.AspNetCore.Components.Web
• Volo.Abp.AspNetCore.Components.Web.Theming
• Volo.Abp.AspNetCore.Components.WebAssembly
• Volo.Abp.AspNetCore.Components.WebAssembly.Theming

Group4 #17074

• Volo.Abp.MultiTenancy.Abstractions
• Volo.Abp.MultiTenancy
• Volo.Abp.AspNetCore.MultiTenancy

Group5 #17094

• Volo.Abp.AspNetCore.Mvc
• Volo.Abp.AspNetCore.Mvc.Client
• Volo.Abp.AspNetCore.Mvc.Client.Common
• Volo.Abp.AspNetCore.Mvc.Contracts
• Volo.Abp.AspNetCore.Mvc.NewtonsoftJson
• Volo.Abp.AspNetCore.Mvc.UI
• Volo.Abp.AspNetCore.Mvc.UI.MultiTenancy
• Volo.Abp.AspNetCore.Mvc.UI.Bootstrap
• Volo.Abp.AspNetCore.Mvc.UI.Bundling
• Volo.Abp.AspNetCore.Mvc.UI.Bundling.Abstractions
• Volo.Abp.AspNetCore.Mvc.UI.Packages
• Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared
• Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo
• Volo.Abp.AspNetCore.Mvc.UI.Widgets

Group6 #17096

• Volo.Abp.AspNetCore.Serilog
• Volo.Abp.AspNetCore.SignalR
• Volo.Abp.AspNetCore.TestBase

Group7 #17108

• Volo.Abp.Auditing
• Volo.Abp.Auditing.Contracts
• Volo.Abp.Authorization
• Volo.Abp.Authorization.Abstractions
• Volo.Abp.AutoMapper
• Volo.Abp.ObjectMapping
• Volo.Abp.Features
• Volo.Abp.FluentValidation
• Volo.Abp.Gdpr.Abstractions
• Volo.Abp.GlobalFeatures
• Volo.Abp.Emailing
• Volo.Abp.MailKit
• Volo.Abp.Swashbuckle
• Volo.Abp.Cli

Group8 #17109

• Volo.Abp.BackgroundJobs
• Volo.Abp.BackgroundJobs.Abstractions
• Volo.Abp.BackgroundJobs.HangFire
• Volo.Abp.BackgroundJobs.Quartz
• Volo.Abp.BackgroundJobs.RabbitMQ
• Volo.Abp.BackgroundWorkers
• Volo.Abp.BackgroundWorkers.Hangfire
• Volo.Abp.BackgroundWorkers.Quartz
• Volo.Abp.HangFire
• Volo.Abp.Quartz
• Volo.Abp.RabbitMQ
• Volo.Abp.AzureServiceBus

Group9 #17120

• Volo.Abp.BlazoriseUI
• Volo.Abp.BlobStoring
• Volo.Abp.BlobStoring.Aliyun
• Volo.Abp.BlobStoring.Aws
• Volo.Abp.BlobStoring.Azure
• Volo.Abp.BlobStoring.FileSystem
• Volo.Abp.BlobStoring.Minio

Group10

• Volo.Abp.Caching Group10: Enable nullable annotations for Volo.Abp.Caching.* #16661
• Volo.Abp.Caching.StackExchangeRedis Group10: Enable nullable annotations for Volo.Abp.Caching.* #16661

Group11

• Volo.Abp.Dapper
• Volo.Abp.Dapr
• Volo.Abp.Ddd.Application
• Volo.Abp.Ddd.Application.Contracts
• Volo.Abp.Ddd.Domain
• Volo.Abp.Ddd.Domain.Shared
• Volo.Abp.DistributedLocking
• Volo.Abp.DistributedLocking.Abstractions
• Volo.Abp.DistributedLocking.Dapr

Group12 #17549

• Volo.Abp.MemoryDb
• Volo.Abp.MongoDB
• Volo.Abp.EntityFrameworkCore
• Volo.Abp.EntityFrameworkCore.MySQL
• Volo.Abp.EntityFrameworkCore.Oracle
• Volo.Abp.EntityFrameworkCore.Oracle.Devart
• Volo.Abp.EntityFrameworkCore.PostgreSql
• Volo.Abp.EntityFrameworkCore.Sqlite
• Volo.Abp.EntityFrameworkCore.SqlServer

Group13 #17557

• Volo.Abp.Kafka
• Volo.Abp.EventBus
• Volo.Abp.EventBus.Abstractions
• Volo.Abp.EventBus.Azure
• Volo.Abp.EventBus.Dapr
• Volo.Abp.EventBus.Kafka
• Volo.Abp.EventBus.RabbitMQ
• Volo.Abp.EventBus.Rebus
• Volo.Abp.AspNetCore.Mvc.Dapr
• Volo.Abp.AspNetCore.Mvc.Dapr.EventBus

Group14 #17560

• Volo.Abp.Http
• Volo.Abp.Http.Abstractions
• Volo.Abp.Http.Client
• Volo.Abp.Http.Client.Dapr
• Volo.Abp.Http.Client.IdentityModel
• Volo.Abp.Http.Client.IdentityModel.MauiBlazor
• Volo.Abp.Http.Client.IdentityModel.Web
• Volo.Abp.Http.Client.IdentityModel.WebAssembly
• Volo.Abp.Http.Client.Web
• Volo.Abp.IdentityModel

Group15 #17561

• Volo.Abp.TextTemplating
• Volo.Abp.TextTemplating.Core
• Volo.Abp.TextTemplating.Razor
• Volo.Abp.TextTemplating.Scriban
• Volo.Abp.Imaging.Abstractions
• Volo.Abp.Imaging.AspNetCore
• Volo.Abp.Imaging.ImageSharp
• Volo.Abp.Imaging.MagickNet
• Volo.Abp.AspNetCore.Mvc.Dapr
• Volo.Abp.AspNetCore.Mvc.Dapr.EventBus
• Volo.Abp.Json

[hikalkan]

Thanks for your effort until now. I moved this issue to 8.0 to track it there. It will be good if we can finish all in 8.0.