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Fix Coverity NullReferenceException Issues w/ Remotes #1083

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Fix Coverity NullReferenceException Issues w/ Remotes #1083

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a1efc7f
fixed a NRE found by Coverity by moving it upstream nearer to the caller
Jun 8, 2015
5e9a99b
minor beautification courtesy of Roslyn
Jun 8, 2015
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16 changes: 8 additions & 8 deletions LibGit2Sharp/Network.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -71,7 +71,7 @@ public virtual IEnumerable<DirectReference> ListReferences(Remote remote, Creden

using (RemoteSafeHandle remoteHandle = Proxy.git_remote_lookup(repository.Handle, remote.Name, true))
{
var gitCallbacks = new GitRemoteCallbacks {version = 1};
var gitCallbacks = new GitRemoteCallbacks { version = 1 };

if (credentialsProvider != null)
{
Expand Down Expand Up @@ -111,13 +111,13 @@ static RemoteSafeHandle BuildRemoteSafeHandle(RepositorySafeHandle repoHandle, R
{
Debug.Assert((remote == null) ^ (url == null));

RemoteSafeHandle remoteHandle;
RemoteSafeHandle remoteHandle = null;

if (url != null)
{
remoteHandle = Proxy.git_remote_create_anonymous(repoHandle, url);
}
else
else if (remote != null)
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We're actually asserting to protect against this. And the call to Debug.Assert is "seen" by Coverity, however it looks like the tool doesn't properly take it into account in the code flow analysis.

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yeah - the ^ operator is the exclusive-or operator.

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Coverity is correct. We in fact do assert but only in debug mode. We then have code flow for when both are null which should be an impossibility. We even dereference a null value in the malformed code flow that we assert, but do not check, will not happen.

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this is correct. However, this is not a public method so we do control all callers of this method. Either way, I agree that this is a bit fragile. What would you think about throwing an exception in the case where we get unexpected input? Or, performing the refactoring suggested in #1084. As you mentioned, I think everyone agrees on the ultimate structure for this code (two methods).

{
remoteHandle = Proxy.git_remote_lookup(repoHandle, remote.Name, true);
}
Expand Down Expand Up @@ -148,14 +148,14 @@ static void DoFetch(RepositorySafeHandle repoHandle, Remote remote, string url,
// Also, if GitRemoteCallbacks were a class instead of a struct, we would need to guard against
// GC occuring in between setting the remote callbacks and actual usage in one of the functions afterwords.
var fetchOptions = new GitFetchOptions
{
RemoteCallbacks = gitCallbacks,
download_tags = Proxy.git_remote_autotag(remoteHandle),
};
{
RemoteCallbacks = gitCallbacks,
download_tags = Proxy.git_remote_autotag(remoteHandle),
};

if (options.TagFetchMode.HasValue)
{
fetchOptions.download_tags = options.TagFetchMode.Value;
fetchOptions.download_tags = options.TagFetchMode.Value;
}

Proxy.git_remote_fetch(remoteHandle, refspecs, fetchOptions, logMessage);
Expand Down