libgit2: fix access to nil t.stdin and improve observability

pkg/git/libgit2/managed/http.go

@@ -292,8 +292,13 @@ func (self *httpSmartSubtransportStream) Free() {
  // ensure body is fully processed and closed
  // for increased likelihood of transport reuse in HTTP/1.x.
  // it should not be a problem to do this more than once.
- _, _ = io.Copy(io.Discard, self.resp.Body) // errors can be safely ignored
- _ = self.resp.Body.Close() // errors can be safely ignored
+ if _, err := io.Copy(io.Discard, self.resp.Body); err != nil {
+ traceLog.Error(err, "[http]: cannot discard response body")
+ }
+
+ if err := self.resp.Body.Close(); err != nil {
+ traceLog.Error(err, "[http]: cannot close response body")
+ }
  }
  }
 }

pkg/git/libgit2/managed/ssh.go

@@ -137,7 +137,9 @@ func (t *sshSmartSubtransport) Action(urlString string, action git2go.SmartServi
  if t.lastAction == git2go.SmartServiceActionUploadpackLs {
  return t.currentStream, nil
  }
- t.Close()
+ if err := t.Close(); err != nil {
+ traceLog.Error(err, "[ssh]: error cleaning up previous stream")
+ }
  }
  cmd = fmt.Sprintf("git-upload-pack '%s'", uPath)
 
@@ -146,7 +148,9 @@ func (t *sshSmartSubtransport) Action(urlString string, action git2go.SmartServi
  if t.lastAction == git2go.SmartServiceActionReceivepackLs {
  return t.currentStream, nil
  }
- t.Close()
+ if err := t.Close(); err != nil {
+ traceLog.Error(err, "[ssh]: error cleaning up previous stream")
+ }
  }
  cmd = fmt.Sprintf("git-receive-pack '%s'", uPath)
 
@@ -161,11 +165,11 @@ func (t *sshSmartSubtransport) Action(urlString string, action git2go.SmartServi
  defer cred.Free()
 
  var addr string
+ port := "22"
  if u.Port() != "" {
- addr = fmt.Sprintf("%s:%s", u.Hostname(), u.Port())
- } else {
- addr = fmt.Sprintf("%s:22", u.Hostname())
+ port = u.Port()
  }
+ addr = fmt.Sprintf("%s:%s", u.Hostname(), port)
 
  ckey, sshConfig, err := cacheKeyAndConfig(addr, cred)
  if err != nil {
@@ -264,19 +268,21 @@ func (t *sshSmartSubtransport) Close() error {
 
  traceLog.Info("[ssh]: sshSmartSubtransport.Close()")
  t.currentStream = nil
- if t.client != nil {
+ if t.client != nil && t.stdin != nil {
  if err := t.stdin.Close(); err != nil {
  returnErr = fmt.Errorf("cannot close stdin: %w", err)
  }
- t.client = nil
  }
+ t.client = nil
+
  if t.session != nil {
  traceLog.Info("[ssh]: skipping session.wait")
  traceLog.Info("[ssh]: session.Close()")
  if err := t.session.Close(); err != nil {
  returnErr = fmt.Errorf("cannot close session: %w", err)
  }
  }
+ t.session = nil
 
  return returnErr
 }
@@ -302,6 +308,10 @@ func (stream *sshSmartSubtransportStream) Free() {
 }
 
 func cacheKeyAndConfig(remoteAddress string, cred *git2go.Credential) (string, *ssh.ClientConfig, error) {
+ if cred == nil {
+ return "", nil, fmt.Errorf("cannot create cache key from a nil credential")
+ }
+
  username, _, privatekey, passphrase, err := cred.GetSSHKey()
  if err != nil {
  return "", nil, err