input: better input arg checking/handling

Improve the handling of input arguments with missing required fields
(e.g., protocol and host).

src/shared/Atlassian.Bitbucket/BitbucketHostProvider.cs

@@ -46,7 +46,10 @@ public bool IsSupported(InputArguments input)
             }
 
             // Split port number and hostname from host input argument
-            input.TryGetHostAndPort(out string hostName, out _);
+            if (!input.TryGetHostAndPort(out string hostName, out _))
+            {
+                return false;
+            }
 
             // We do not support unencrypted HTTP communications to Bitbucket,
             // but we report `true` here for HTTP so that we can show a helpful

src/shared/GitHub/GitHubHostProvider.cs

@@ -63,7 +63,10 @@ public override bool IsSupported(InputArguments input)
             }
 
             // Split port number and hostname from host input argument
-            input.TryGetHostAndPort(out string hostName, out _);
+            if (!input.TryGetHostAndPort(out string hostName, out _))
+            {
+                return false;
+            }
 
             if (StringComparer.OrdinalIgnoreCase.Equals(hostName, GitHubConstants.GitHubBaseUrlHost) ||
                 StringComparer.OrdinalIgnoreCase.Equals(hostName, GitHubConstants.GistBaseUrlHost))

src/shared/Microsoft.Git.CredentialManager.Tests/Commands/EraseCommandTests.cs

@@ -16,9 +16,11 @@ public async Task EraseCommand_ExecuteAsync_CallsHostProvider()
         {
             const string testUserName = "john.doe";
             const string testPassword = "letmein123"; // [SuppressMessage("Microsoft.Security", "CS001:SecretInline", Justification="Fake credential")]
-            var stdin = $"username={testUserName}\npassword={testPassword}\n\n";
+            var stdin = $"protocol=http\nhost=example.com\nusername={testUserName}\npassword={testPassword}\n\n";
             var expectedInput = new InputArguments(new Dictionary<string, string>
             {
+                ["protocol"] = "http",
+                ["host"]     = "example.com",
                 ["username"] = testUserName,
                 ["password"] = testPassword // [SuppressMessage("Microsoft.Security", "CS001:SecretInline", Justification="Fake credential")]
             });

src/shared/Microsoft.Git.CredentialManager.Tests/Commands/GetCommandTests.cs

@@ -19,8 +19,11 @@ public async Task GetCommand_ExecuteAsync_CallsHostProviderAndWritesCredential()
             const string testUserName = "john.doe";
             const string testPassword = "letmein123"; // [SuppressMessage("Microsoft.Security", "CS001:SecretInline", Justification="Fake credential")]
             ICredential testCredential = new GitCredential(testUserName, testPassword);
+            var stdin = $"protocol=http\nhost=example.com\n\n";
             var expectedStdOutDict = new Dictionary<string, string>
             {
+                ["protocol"] = "http",
+                ["host"]     = "example.com",
                 ["username"] = testUserName,
                 ["password"] = testPassword
             };
@@ -29,7 +32,10 @@ public async Task GetCommand_ExecuteAsync_CallsHostProviderAndWritesCredential()
             providerMock.Setup(x => x.GetCredentialAsync(It.IsAny<InputArguments>()))
                         .ReturnsAsync(testCredential);
             var providerRegistry = new TestHostProviderRegistry {Provider = providerMock.Object};
-            var context = new TestCommandContext();
+            var context = new TestCommandContext
+            {
+                Streams = {In = stdin}
+            };
 
             var command = new GetCommand(context, providerRegistry);
 

src/shared/Microsoft.Git.CredentialManager.Tests/Commands/StoreCommandTests.cs

@@ -15,9 +15,11 @@ public async Task StoreCommand_ExecuteAsync_CallsHostProvider()
         {
             const string testUserName = "john.doe";
             const string testPassword = "letmein123"; // [SuppressMessage("Microsoft.Security", "CS001:SecretInline", Justification="Fake credential")]
-            var stdin = $"username={testUserName}\npassword={testPassword}\n\n";
+            var stdin = $"protocol=http\nhost=example.com\nusername={testUserName}\npassword={testPassword}\n\n";
             var expectedInput = new InputArguments(new Dictionary<string, string>
             {
+                ["protocol"] = "http",
+                ["host"]     = "example.com",
                 ["username"] = testUserName,
                 ["password"] = testPassword
             });

src/shared/Microsoft.Git.CredentialManager/Commands/GitCommandBase.cs

@@ -39,6 +39,9 @@ internal async Task ExecuteAsync()
             IDictionary<string, string> inputDict = await Context.Streams.In.ReadDictionaryAsync(StringComparer.Ordinal);
             var input = new InputArguments(inputDict);
 
+            // Validate minimum arguments are present
+            EnsureMinimumInputArguments(input);
+
             // Set the remote URI to scope settings to throughout the process from now on
             Context.Settings.RemoteUri = input.GetRemoteUri();
 
@@ -53,6 +56,29 @@ internal async Task ExecuteAsync()
             Context.Trace.WriteLine($"End '{Name}' command...");
         }
 
+        protected virtual void EnsureMinimumInputArguments(InputArguments input)
+        {
+            if (input.Protocol is null)
+            {
+                throw new InvalidOperationException("Missing 'protocol' input argument");
+            }
+
+            if (string.IsNullOrWhiteSpace(input.Protocol))
+            {
+                throw new InvalidOperationException("Invalid 'protocol' input argument (cannot be empty)");
+            }
+
+            if (input.Host is null)
+            {
+                throw new InvalidOperationException("Missing 'host' input argument");
+            }
+
+            if (string.IsNullOrWhiteSpace(input.Host))
+            {
+                throw new InvalidOperationException("Invalid 'host' input argument (cannot be empty)");
+            }
+        }
+
         /// <summary>
         /// Execute the command using the given <see cref="InputArguments"/> and <see cref="IHostProvider"/>.
         /// </summary>

src/shared/Microsoft.Git.CredentialManager/Commands/StoreCommand.cs

@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
+using System;
 using System.Threading.Tasks;
 
 namespace Microsoft.Git.CredentialManager.Commands
@@ -16,5 +17,21 @@ protected override Task ExecuteInternalAsync(InputArguments input, IHostProvider
         {
             return provider.StoreCredentialAsync(input);
         }
+
+        protected override void EnsureMinimumInputArguments(InputArguments input)
+        {
+            base.EnsureMinimumInputArguments(input);
+
+            // An empty string username/password are valid inputs, so only check for `null` (not provided)
+            if (input.UserName is null)
+            {
+                throw new InvalidOperationException("Missing 'username' input argument");
+            }
+
+            if (input.Password is null)
+            {
+                throw new InvalidOperationException("Missing 'password' input argument");
+            }
+        }
     }
 }