Add null checks everywhere in dependency model

src/Microsoft.Extensions.DependencyModel/CompilationLibrary.cs

@@ -19,6 +19,10 @@ namespace Microsoft.Extensions.DependencyModel
             bool serviceable)
             : base(type, name, version, hash,  dependencies, serviceable)
         {
+            if (assemblies == null)
+            {
+                throw new ArgumentNullException(nameof(assemblies));
+            }
             Assemblies = assemblies.ToArray();
         }
 

src/Microsoft.Extensions.DependencyModel/CompilationOptions.cs

@@ -1,6 +1,7 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -8,7 +9,7 @@ namespace Microsoft.Extensions.DependencyModel
 {
     public class CompilationOptions
     {
-        public IEnumerable<string> Defines { get; }
+        public IReadOnlyList<string> Defines { get; }
 
         public string LanguageVersion { get; }
 
@@ -59,7 +60,11 @@ namespace Microsoft.Extensions.DependencyModel
             bool? emitEntryPoint,
             bool? generateXmlDocumentation)
         {
-            Defines = defines;
+            if (defines == null)
+            {
+                throw new ArgumentNullException(nameof(defines));
+            }
+            Defines = defines.ToArray();
             LanguageVersion = languageVersion;
             Platform = platform;
             AllowUnsafe = allowUnsafe;

src/Microsoft.Extensions.DependencyModel/Dependency.cs

@@ -1,6 +1,7 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
+using System;
 using Microsoft.Extensions.Internal;
 
 namespace Microsoft.Extensions.DependencyModel
@@ -9,6 +10,14 @@ namespace Microsoft.Extensions.DependencyModel
     {
         public Dependency(string name, string version)
         {
+            if (string.IsNullOrEmpty(name))
+            {
+                throw new ArgumentException(nameof(name));
+            }
+            if (string.IsNullOrEmpty(version))
+            {
+                throw new ArgumentException(nameof(version));
+            }
             Name = name;
             Version = version;
         }

src/Microsoft.Extensions.DependencyModel/DependencyContext.cs

@@ -21,13 +21,9 @@ namespace Microsoft.Extensions.DependencyModel
             IEnumerable<RuntimeLibrary> runtimeLibraries,
             IEnumerable<RuntimeFallbacks> runtimeGraph)
         {
-            if (targetFramework == null)
+            if (string.IsNullOrEmpty(targetFramework))
             {
-                throw new ArgumentNullException(nameof(targetFramework));
-            }
-            if (runtime == null)
-            {
-                throw new ArgumentNullException(nameof(runtime));
+                throw new ArgumentException(nameof(targetFramework));
             }
             if (compilationOptions == null)
             {

src/Microsoft.Extensions.DependencyModel/DependencyContextCsvReader.cs

@@ -13,6 +13,10 @@ namespace Microsoft.Extensions.DependencyModel
     {
         public DependencyContext Read(Stream stream)
         {
+            if (stream == null)
+            {
+                throw new ArgumentNullException(nameof(stream));
+            }
             var lines = new List<DepsFileLine>();
             using (var reader = new StreamReader(stream))
             {

src/Microsoft.Extensions.DependencyModel/DependencyContextJsonReader.cs

@@ -14,6 +14,10 @@ namespace Microsoft.Extensions.DependencyModel
     {
         public DependencyContext Read(Stream stream)
         {
+            if (stream == null)
+            {
+                throw new ArgumentNullException(nameof(stream));
+            }
             using (var streamReader = new StreamReader(stream))
             {
                 using (var reader = new JsonTextReader(streamReader))

src/Microsoft.Extensions.DependencyModel/DependencyContextLoader.cs

@@ -49,7 +49,7 @@ namespace Microsoft.Extensions.DependencyModel
 
         internal virtual bool IsEntryAssembly(Assembly assembly)
         {
-            return assembly.GetName() == Assembly.GetEntryAssembly().GetName();
+            return assembly.GetName() == Assembly.GetEntryAssembly()?.GetName();
         }
 
         internal virtual Stream GetResourceStream(Assembly assembly, string name)
@@ -166,7 +166,7 @@ namespace Microsoft.Extensions.DependencyModel
 
         private static string[] GetHostDepsList()
         {
-            // TODO: Were going to replace this with AppContext.GetData
+            // TODO: We're going to replace this with AppContext.GetData
             var appDomainType = typeof(object).GetTypeInfo().Assembly?.GetType("System.AppDomain");
             var currentDomain = appDomainType?.GetProperty("CurrentDomain")?.GetValue(null);
             var deps = appDomainType?.GetMethod("GetData")?.Invoke(currentDomain, new[] { "APP_CONTEXT_DEPS_FILES" });

src/Microsoft.Extensions.DependencyModel/DependencyContextWriter.cs

@@ -16,6 +16,14 @@ namespace Microsoft.Extensions.DependencyModel
     {
         public void Write(DependencyContext context, Stream stream)
         {
+            if (context == null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+            if (stream == null)
+            {
+                throw new ArgumentNullException(nameof(stream));
+            }
             using (var writer = new StreamWriter(stream))
             {
                 using (var jsonWriter = new JsonTextWriter(writer) { Formatting = Formatting.Indented })

src/Microsoft.Extensions.DependencyModel/Library.cs

@@ -1,6 +1,7 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
+using System;
 using System.Linq;
 using System.Collections.Generic;
 
@@ -10,6 +11,27 @@ namespace Microsoft.Extensions.DependencyModel
     {
         public Library(string type, string name, string version, string hash, IEnumerable<Dependency> dependencies, bool serviceable)
         {
+            if (string.IsNullOrEmpty(type))
+            {
+                throw new ArgumentException(nameof(type));
+            }
+            if (string.IsNullOrEmpty(name))
+            {
+                throw new ArgumentException(nameof(name));
+            }
+            if (string.IsNullOrEmpty(version))
+            {
+                throw new ArgumentException(nameof(version));
+            }
+            // Hash could be empty for projects
+            if (hash == null)
+            {
+                throw new ArgumentException(nameof(hash));
+            }
+            if (dependencies == null)
+            {
+                throw new ArgumentNullException(nameof(dependencies));
+            }
             Type = type;
             Name = name;
             Version = version;

src/Microsoft.Extensions.DependencyModel/ResourceAssembly.cs

@@ -1,12 +1,22 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
+using System;
+
 namespace Microsoft.Extensions.DependencyModel
 {
     public class ResourceAssembly
     {
         public ResourceAssembly(string path, string locale)
         {
+            if (string.IsNullOrEmpty(path))
+            {
+                throw new ArgumentException(nameof(path));
+            }
+            if (string.IsNullOrEmpty(locale))
+            {
+                throw new ArgumentException(nameof(locale));
+            }
             Locale = locale;
             Path = path;
         }

src/Microsoft.Extensions.DependencyModel/RuntimeAssembly.cs

@@ -15,6 +15,14 @@ namespace Microsoft.Extensions.DependencyModel
 
         public RuntimeAssembly(string assemblyName, string path)
         {
+            if (string.IsNullOrEmpty(assemblyName))
+            {
+                throw new ArgumentException(nameof(assemblyName));
+            }
+            if (string.IsNullOrEmpty(path))
+            {
+                throw new ArgumentException(nameof(path));
+            }
             _assemblyName = assemblyName;
             Path = path;
         }

src/Microsoft.Extensions.DependencyModel/RuntimeFallbacks.cs

@@ -14,9 +14,9 @@ namespace Microsoft.Extensions.DependencyModel
 
         public RuntimeFallbacks(string runtime, IEnumerable<string> fallbacks)
         {
-            if (runtime == null)
+            if (string.IsNullOrEmpty(runtime))
             {
-                throw new ArgumentNullException(nameof(runtime));
+                throw new ArgumentException(nameof(runtime));
             }
             if (fallbacks == null)
             {

src/Microsoft.Extensions.DependencyModel/RuntimeLibrary.cs

@@ -1,6 +1,7 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -21,6 +22,22 @@ namespace Microsoft.Extensions.DependencyModel
             bool serviceable)
             : base(type, name, version, hash, dependencies, serviceable)
         {
+            if (assemblies == null)
+            {
+                throw new ArgumentNullException(nameof(assemblies));
+            }
+            if (nativeLibraries == null)
+            {
+                throw new ArgumentNullException(nameof(nativeLibraries));
+            }
+            if (resourceAssemblies == null)
+            {
+                throw new ArgumentNullException(nameof(resourceAssemblies));
+            }
+            if (subTargets == null)
+            {
+                throw new ArgumentNullException(nameof(subTargets));
+            }
             Assemblies = assemblies.ToArray();
             ResourceAssemblies = resourceAssemblies.ToArray();
             RuntimeTargets = subTargets.ToArray();

src/Microsoft.Extensions.DependencyModel/RuntimeTarget.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -7,6 +8,18 @@ namespace Microsoft.Extensions.DependencyModel
     {
         public RuntimeTarget(string runtime, IEnumerable<RuntimeAssembly> assemblies, IEnumerable<string> nativeLibraries)
         {
+            if (string.IsNullOrEmpty(runtime))
+            {
+                throw new ArgumentException(nameof(runtime));
+            }
+            if (assemblies == null)
+            {
+                throw new ArgumentNullException(nameof(assemblies));
+            }
+            if (nativeLibraries == null)
+            {
+                throw new ArgumentNullException(nameof(nativeLibraries));
+            }
             Runtime = runtime;
             Assemblies = assemblies.ToArray();
             NativeLibraries = nativeLibraries.ToArray();