(GH-1248) Fix - multiple sources w/same base url fail

Previously, when matching to an authenticated source that uses
credentials, Chocolatey used the first source it found, even if there
may have been multiple sources. Instead build a list of candidate
sources by matching host (base url), and if multiple sources are found,
then match against the full source url for a match. If that
fails, fall back to the previous behavior of using the first found
source.

src/chocolatey/infrastructure.app/nuget/ChocolateyNugetCredentialProvider.cs

@@ -19,6 +19,7 @@ namespace chocolatey.infrastructure.app.nuget
     using System;
     using System.Linq;
     using System.Net;
+    using System.Text.RegularExpressions;
     using commandline;
     using NuGet;
     using configuration;
@@ -49,8 +50,11 @@ public ICredentials GetCredentials(Uri uri, IWebProxy proxy, CredentialType cred
             }
 
             var configSourceUri = new Uri(INVALID_URL);
+
+            this.Log().Debug(ChocolateyLoggers.Verbose, "Attempting to gather credentials for '{0}'".format_with(uri.OriginalString));
             try
             {
+                // the source to validate against is typically passed in
                 var firstSpecifiedSource = _config.Sources.to_string().Split(new[] { ';' }, StringSplitOptions.RemoveEmptyEntries).FirstOrDefault().to_string();
                 if (!string.IsNullOrWhiteSpace(firstSpecifiedSource))
                 {
@@ -62,6 +66,7 @@ public ICredentials GetCredentials(Uri uri, IWebProxy proxy, CredentialType cred
                 this.Log().Warn("Cannot determine uri from specified source:{0} {1}".format_with(Environment.NewLine, ex.Message));
             }
 
+            // did the user pass credentials and a source?
             if (_config.Sources.TrimEnd('/').is_equal_to(uri.OriginalString.TrimEnd('/')) || configSourceUri.Host.is_equal_to(uri.Host))
             {
                 if (!string.IsNullOrWhiteSpace(_config.SourceCommand.Username) && !string.IsNullOrWhiteSpace(_config.SourceCommand.Password))
@@ -72,16 +77,13 @@ public ICredentials GetCredentials(Uri uri, IWebProxy proxy, CredentialType cred
                 }
             }
 
-            var source = _config.MachineSources.FirstOrDefault(s =>
+            // credentials were not explicit
+            // discover based on closest match in sources
+            var candidateSources = _config.MachineSources.Where(
+                s =>
                 {
                     var sourceUrl = s.Key.TrimEnd('/');
 
-                    var equalAtFullUri = sourceUrl.is_equal_to(uri.OriginalString.TrimEnd('/'))
-                       && !string.IsNullOrWhiteSpace(s.Username)
-                       && !string.IsNullOrWhiteSpace(s.EncryptedPassword);
-
-                    if (equalAtFullUri) return true;
-
                     try
                     {
                         var sourceUri = new Uri(sourceUrl);
@@ -95,15 +97,49 @@ public ICredentials GetCredentials(Uri uri, IWebProxy proxy, CredentialType cred
                     }
 
                     return false;
-                });
+                }).ToList();
+
+            MachineSourceConfiguration source = null;
+
+
+            if (candidateSources.Count == 1)
+            {
+                // only one match, use it
+                source = candidateSources.FirstOrDefault();
+            }
+            else if (candidateSources.Count > 1)
+            {
+                // find the source that is the closest match
+                foreach (var candidateSource in candidateSources.or_empty_list_if_null())
+                {
+                    var candidateRegEx = new Regex(Regex.Escape(candidateSource.Key.TrimEnd('/')),RegexOptions.CultureInvariant | RegexOptions.IgnoreCase);
+                    if (candidateRegEx.IsMatch(uri.OriginalString.TrimEnd('/')))
+                    {
+                        this.Log().Debug("Source selected will be '{0}'".format_with(candidateSource.Key.TrimEnd('/')));
+                        source = candidateSource;
+                        break;
+                    }
+                }
+
+                if (source == null && !retrying)
+                {
+                    // use the first source. If it fails, fall back to grabbing credentials from the user
+                    var candidateSource = candidateSources.First();
+                    this.Log().Debug("Evaluated {0} candidate sources but was unable to find a match, using {1}".format_with(candidateSources.Count, candidateSource.Key.TrimEnd('/')));
+                    source = candidateSource;
+                }
+            }
 
             if (source == null)
             {
+                this.Log().Debug("Asking user for credentials for '{0}'".format_with(uri.OriginalString));
                 return get_credentials_from_user(uri, proxy, credentialType);
             }
-
-            this.Log().Debug("Using saved credentials");
-
+            else
+            {
+                this.Log().Debug("Using saved credentials");
+            }
+
             return new NetworkCredential(source.Username, NugetEncryptionUtility.DecryptString(source.EncryptedPassword));
         }