Merge pull request #600 from mjcheetham/tty-pref

Add option to disable GUI prompts/prefer terminal prompts instead

Author: mjcheetham

docs/configuration.md

@@ -106,6 +106,25 @@ git config --global credential.ghe.contoso.com.authority github
 
 ---
 
+### credential.guiPrompt
+
+Permit or disable GCM from presenting GUI prompts. If an equivalent terminal/
+text-based prompt is available, that will be shown instead.
+
+To disable all interactivity see [credential.interactive](#credentialinteractive).
+
+#### Example
+
+```shell
+git config --global credential.guiPrompt false
+```
+
+Defaults to enabled.
+
+**Also see: [GCM_GUI_PROMPT](environment.md#GCM_GUI_PROMPT)**
+
+---
+
 ### credential.autoDetectTimeout
 
 Set the maximum length of time, in milliseconds, that GCM should wait for a

docs/environment.md

@@ -226,6 +226,33 @@ export GCM_AUTHORITY=github
 
 ---
 
+### GCM_GUI_PROMPT
+
+Permit or disable GCM from presenting GUI prompts. If an equivalent terminal/
+text-based prompt is available, that will be shown instead.
+
+To disable all interactivity see [GCM_INTERACTIVE](#gcm_interactive).
+
+#### Example
+
+##### Windows
+
+```batch
+SET GCM_GUI_PROMPT=0
+```
+
+##### macOS/Linux
+
+```bash
+export GCM_GUI_PROMPT=0
+```
+
+Defaults to enabled.
+
+**Also see: [credential.guiPrompt](configuration.md#credentialguiprompt)**
+
+---
+
 ### GCM_AUTODETECT_TIMEOUT
 
 Set the maximum length of time, in milliseconds, that GCM should wait for a

docs/faq.md

@@ -109,3 +109,30 @@ Follow the instructions in [our WSL guide](wsl.md) carefully. Especially note th
 ### Does GCM work with multiple users? If so, how?
 
 That's a fairly complicated question to answer, but in short, yes. See [our document on multiple users](multiple-users.md) for details.
+
+### How can I disable GUI dialogs and prompts?
+
+There are various environment variables and configuration options available to
+customize how GCM will prompt you (or not) for input. Please see the following:
+
+- [`GCM_INTERACTIVE`](environment.md#GCM_INTERACTIVE) / [`credential.interactive`](configuration.md#credentialinteractive)
+- [`GCM_GUI_PROMPT`](environment.md#GCM_GUI_PROMPT) / [`credential.guiPrompt`](configuration.md#credentialguiprompt)
+- [`GIT_TERMINAL_PROMPT`](https://git-scm.com/docs/git#Documentation/git.txt-codeGITTERMINALPROMPTcode) (note this is a _Git setting_ that will affect Git as well as GCM)
+
+### How can I extend GUI prompts/integrate prompts with my application?
+
+Application developers who use Git - think Visual Studio, GitKraken, etc. - may
+want to replace the GCM default UI with prompts styled to look like their
+application. This isn't complicated (though it is a bit of work).
+
+You can replace the GUI prompts of the Bitbucket and GitHub host providers
+specifically by using the `credential.gitHubHelper`/`credential.bitbucketHelper`
+settings or `GCM_GITHUB_HELPER`/`GCM_BITBUCKET_HELPER` environment variables.
+
+Set these variables to the path of an external helper executable that responds
+to the requests as the bundled UI helpers do. See the current `--help` documents
+for the bundled UI helpers (`GitHub.UI`/`Atlassian.Bitbucket.UI`) for more
+information.
+
+You may also set these variables to the empty string `""` to force terminal/
+text-based prompts instead.

src/shared/Atlassian.Bitbucket/BitbucketAuthentication.cs

@@ -90,7 +90,8 @@ public async Task<CredentialsPromptResult> GetCredentialsAsync(Uri targetUri, st
             }
 
             // Shell out to the UI helper and show the Bitbucket u/p prompt
-            if (Context.SessionManager.IsDesktopSession && TryFindHelperExecutablePath(out string helperPath))
+            if (Context.Settings.IsGuiPromptsEnabled && Context.SessionManager.IsDesktopSession &&
+                TryFindHelperExecutablePath(out string helperPath))
             {
                 var cmdArgs = new StringBuilder("userpass");
                 if (!string.IsNullOrWhiteSpace(userName))
@@ -186,7 +187,8 @@ public async Task<bool> ShowOAuthRequiredPromptAsync()
             ThrowIfUserInteractionDisabled();
 
             // Shell out to the UI helper and show the Bitbucket prompt
-            if (Context.SessionManager.IsDesktopSession && TryFindHelperExecutablePath(out string helperPath))
+            if (Context.Settings.IsGuiPromptsEnabled && Context.SessionManager.IsDesktopSession &&
+                TryFindHelperExecutablePath(out string helperPath))
             {
                 IDictionary<string, string> output = await InvokeHelperAsync(helperPath, "oauth");
 

src/shared/Core/Authentication/AuthenticationBase.cs

@@ -3,8 +3,6 @@
 using System.Diagnostics;
 using System.IO;
 using System.Linq;
-using System.Reflection;
-using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -92,6 +90,16 @@ protected void ThrowIfUserInteractionDisabled()
             }
         }
 
+        protected void ThrowIfGuiPromptsDisabled()
+        {
+            if (!Context.Settings.IsGuiPromptsEnabled)
+            {
+                Context.Trace.WriteLine($"{Constants.EnvironmentVariables.GitTerminalPrompts} is 0; GUI prompts have been disabled.");
+
+                throw new InvalidOperationException("Cannot show prompt because GUI prompts have been disabled.");
+            }
+        }
+
         protected void ThrowIfTerminalPromptsDisabled()
         {
             if (!Context.Settings.IsTerminalPromptsEnabled)

src/shared/Core/Authentication/BasicAuthentication.cs

@@ -32,7 +32,8 @@ public ICredential GetCredentials(string resource, string userName)
             ThrowIfUserInteractionDisabled();
 
             // TODO: we only support system GUI prompts on Windows currently
-            if (Context.SessionManager.IsDesktopSession && PlatformUtils.IsWindows())
+            if (Context.Settings.IsGuiPromptsEnabled && Context.SessionManager.IsDesktopSession &&
+                PlatformUtils.IsWindows())
             {
                 return GetCredentialsByUi(resource, userName);
             }

src/shared/Core/Constants.cs

@@ -86,6 +86,7 @@ public static class EnvironmentVariables
             public const string GitExecutablePath     = "GIT_EXEC_PATH";
             public const string GpgExecutablePath     = "GCM_GPG_PATH";
             public const string GcmAutoDetectTimeout  = "GCM_AUTODETECT_TIMEOUT";
+            public const string GcmGuiPromptsEnabled  = "GCM_GUI_PROMPT";
         }
 
         public static class Http
@@ -120,6 +121,7 @@ public static class Credential
                 public const string DpapiStorePath = "dpapiStorePath";
                 public const string UserName = "username";
                 public const string AutoDetectTimeout = "autoDetectTimeout";
+                public const string GuiPromptsEnabled = "guiPrompt";
             }
 
             public static class Http

src/shared/Core/Settings.cs

@@ -65,6 +65,14 @@ public interface ISettings : IDisposable
         /// </summary>
         bool IsTerminalPromptsEnabled { get; }
 
+        /// <summary>
+        /// True if GUI prompts are enabled, false otherwise.
+        /// </summary>
+        /// <remarks>
+        /// If GUI prompts are disabled but an equivalent terminal prompt is available, the latter will be used instead.
+        /// </remarks>
+        bool IsGuiPromptsEnabled { get; }
+
         /// <summary>
         /// True if it is permitted to interact with the user, false otherwise.
         /// </summary>
@@ -437,6 +445,25 @@ protected virtual bool TryGetExternalDefault(string section, string property, ou
 
         public bool IsTerminalPromptsEnabled => _environment.Variables.GetBooleanyOrDefault(KnownEnvars.GitTerminalPrompts, true);
 
+        public bool IsGuiPromptsEnabled
+        {
+            get
+            {
+                const bool defaultValue = true;
+
+                if (TryGetSetting(
+                        KnownEnvars.GcmGuiPromptsEnabled,
+                        KnownGitCfg.Credential.SectionName,
+                        KnownGitCfg.Credential.GuiPromptsEnabled,
+                        out string str))
+                {
+                    return str.ToBooleanyOrDefault(defaultValue);
+                }
+
+                return defaultValue;
+            }
+        }
+
         public bool IsInteractionAllowed
         {
             get

src/shared/GitHub/GitHubAuthentication.cs

@@ -81,11 +81,13 @@ public async Task<AuthenticationPromptResult> GetAuthenticationAsync(Uri targetU
             if (modes == AuthenticationModes.Browser ||
                 modes == AuthenticationModes.Device)
             {
-                    return new AuthenticationPromptResult(modes);
+                return new AuthenticationPromptResult(modes);
             }
 
             ThrowIfUserInteractionDisabled();
-            if (Context.SessionManager.IsDesktopSession && TryFindHelperExecutablePath(out string helperPath))
+
+            if (Context.Settings.IsGuiPromptsEnabled && Context.SessionManager.IsDesktopSession &&
+                TryFindHelperExecutablePath(out string helperPath))
             {
                 var promptArgs = new StringBuilder("prompt");
                 if (modes == AuthenticationModes.All)
@@ -213,7 +215,8 @@ public async Task<string> GetTwoFactorCodeAsync(Uri targetUri, bool isSms)
         {
             ThrowIfUserInteractionDisabled();
 
-            if (Context.SessionManager.IsDesktopSession && TryFindHelperExecutablePath(out string helperPath))
+            if (Context.Settings.IsGuiPromptsEnabled && Context.SessionManager.IsDesktopSession &&
+                TryFindHelperExecutablePath(out string helperPath))
             {
                 var args = new StringBuilder("2fa");
                 if (isSms) args.Append(" --sms");
@@ -282,7 +285,8 @@ public async Task<OAuth2TokenResult> GetOAuthTokenViaDeviceCodeAsync(Uri targetU
             OAuth2DeviceCodeResult dcr = await oauthClient.GetDeviceCodeAsync(scopes, CancellationToken.None);
 
             // If we have a desktop session show the device code in a dialog
-            if (Context.SessionManager.IsDesktopSession && TryFindHelperExecutablePath(out string helperPath))
+            if (Context.Settings.IsGuiPromptsEnabled && Context.SessionManager.IsDesktopSession &&
+                TryFindHelperExecutablePath(out string helperPath))
             {
                 var args = new StringBuilder("device");
                 args.AppendFormat(" --code {0} ", QuoteCmdArg(dcr.UserCode));

src/shared/TestInfrastructure/Objects/TestSettings.cs

@@ -13,6 +13,8 @@ public class TestSettings : ISettings
 
         public bool IsTerminalPromptsEnabled { get; set; } = true;
 
+        public bool IsGuiPromptsEnabled { get; set; } = true;
+
         public bool IsInteractionAllowed { get; set; } = true;
 
         public string Trace { get; set; }
@@ -97,6 +99,8 @@ public IEnumerable<string> GetSettingValues(string envarName, string section, st
 
         bool ISettings.IsTerminalPromptsEnabled => IsTerminalPromptsEnabled;
 
+        bool ISettings.IsGuiPromptsEnabled => IsGuiPromptsEnabled;
+
         bool ISettings.IsInteractionAllowed => IsInteractionAllowed;
 
         bool ISettings.GetTracingEnabled(out string value)