Use credentials provider as the URIish password auth is broken

Because of the merged change in JGit [1] that introduces the
ability to use the ~/.netrc credentials, all the JGit commands on
private repositories are broken [2].

In order to get around this problem we need to avoid using the URIish
credentials and explicitly provide a not-null CredentialsProvider
that uses the underlying GitHub OAuth credentials for the HTTP BasicAuth
handshake.

[1] https://git.eclipse.org/r/#/c/22194/
[2] https://groups.google.com/forum/#!topic/repo-discuss/t_yYD2IGYS0

Change-Id: I6723990da79ebeec96e80389d81d6f3233668694

github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/GitCloneStep.java

diff --git a/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/GitCloneStep.java b/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/GitCloneStep.java
index 464f252..b1302f1 100644
--- a/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/GitCloneStep.java
+++ b/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/GitCloneStep.java
@@ -79,6 +79,7 @@
   public void doImport(ProgressMonitor progress) throws GitCloneFailedException,
       GitDestinationAlreadyExistsException, GitDestinationNotWritableException {
     CloneCommand clone = new CloneCommand();
+    clone.setCredentialsProvider(getRepository().getCredentialsProvider());
     String sourceUri = getSourceUri();
     clone.setURI(sourceUri);
     clone.setBare(true);

github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/GitHubRepository.java

diff --git a/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/GitHubRepository.java b/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/GitHubRepository.java
index a677958..9544984 100644
--- a/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/GitHubRepository.java
+++ b/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/GitHubRepository.java
@@ -17,6 +17,10 @@
 
 import lombok.experimental.Delegate;
 
+import org.eclipse.jgit.errors.UnsupportedCredentialItem;
+import org.eclipse.jgit.transport.CredentialItem;
+import org.eclipse.jgit.transport.CredentialsProvider;
+import org.eclipse.jgit.transport.URIish;
 import org.kohsuke.github.GHRepository;
 
 import com.google.inject.Inject;
@@ -41,8 +45,7 @@
   private GHRepository ghRepository;
 
   public String getCloneUrl() {
-    return cloneUrl.replace("://", "://" + ghLogin.getMyself().getLogin() + ":"
-        + ghLogin.getToken().accessToken + "@");
+    return cloneUrl.replace("://", "://" + ghLogin.getMyself().getLogin() + "@");
   }
 
   public String getOrganisation() {
@@ -65,4 +68,56 @@
     this.ghRepository =
         ghLogin.getHub().getRepository(organisation + "/" + repository);
   }
+
+  public CredentialsProvider getCredentialsProvider() {
+    return new CredentialsProvider() {
+
+      @Override
+      public boolean supports(CredentialItem... items) {
+        for (CredentialItem i : items) {
+          if (i instanceof CredentialItem.Username) {
+            continue;
+          } else if (i instanceof CredentialItem.Password) {
+            continue;
+          } else {
+            return false;
+          }
+        }
+        return true;
+      }
+
+      @Override
+      public boolean isInteractive() {
+        return false;
+      }
+
+      @Override
+      public boolean get(URIish uri, CredentialItem... items)
+          throws UnsupportedCredentialItem {
+        String username = uri.getUser();
+        if (username == null) {
+          username = ghLogin.getMyself().getLogin();
+        }
+        if (username == null) {
+          return false;
+        }
+
+        String password = ghLogin.getToken().accessToken;
+        if (password == null) {
+          return false;
+        }
+
+        for (CredentialItem i : items) {
+          if (i instanceof CredentialItem.Username) {
+            ((CredentialItem.Username) i).setValue(username);
+          } else if (i instanceof CredentialItem.Password) {
+            ((CredentialItem.Password) i).setValue(password.toCharArray());
+          } else {
+            throw new UnsupportedCredentialItem(uri, i.getPromptText());
+          }
+        }
+        return true;
+      }
+    };
+  }
 }

github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/PullRequestImportJob.java

diff --git a/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/PullRequestImportJob.java b/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/PullRequestImportJob.java
index 3f199be..89f3454 100644
--- a/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/PullRequestImportJob.java
+++ b/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/git/PullRequestImportJob.java
@@ -246,6 +246,7 @@
     fetch.setRefSpecs(new RefSpec("+refs/pull/" + pr.getNumber()
         + "/head:refs/remotes/origin/pr/" + pr.getNumber()));
     fetch.setProgressMonitor(this);
+    fetch.setCredentialsProvider(ghRepository.getCredentialsProvider());
     fetch.call();
   }