evidence: improve amnesia evidence handling (#5003)

fix bug so that PotentialAmnesiaEvidence is being gossiped

handle inbound amnesia evidence correctly

add method to check if potential amnesia evidence is on trial

fix a bug with the height when we upgrade to amnesia evidence

change evidence to using just pointers.

More logging in the evidence module

Co-authored-by: Marko <marbar3778@yahoo.com>

light/client.go

@@ -975,7 +975,7 @@ func (c *Client) compareNewHeaderWithWitnesses(h *types.SignedHeader) error {
 				headerMatched = true
 			case ErrConflictingHeaders: // potential fork
 				c.logger.Error(err.Error(), "witness", e.Witness)
-				c.sendConflictingHeadersEvidence(types.ConflictingHeadersEvidence{H1: h, H2: e.H2})
+				c.sendConflictingHeadersEvidence(&types.ConflictingHeadersEvidence{H1: h, H2: e.H2})
 				lastErrConfHeaders = e
 			case errBadWitness:
 				c.logger.Error(err.Error(), "witness", c.witnesses[e.WitnessIndex])
@@ -1188,7 +1188,7 @@ func (c *Client) validateValidatorSet(vals *types.ValidatorSet) error {
 //
 // Evidence needs to be submitted to all full nodes since there's no way to
 // determine which full node is correct (honest).
-func (c *Client) sendConflictingHeadersEvidence(ev types.ConflictingHeadersEvidence) {
+func (c *Client) sendConflictingHeadersEvidence(ev *types.ConflictingHeadersEvidence) {
 	err := c.primary.ReportEvidence(ev)
 	if err != nil {
 		c.logger.Error("Failed to report evidence to primary", "ev", ev, "primary", c.primary)

light/client_test.go

@@ -1083,7 +1083,7 @@ func TestClientReportsConflictingHeadersEvidence(t *testing.T) {
 	}
 
 	// Check evidence was sent to both full nodes.
-	ev := types.ConflictingHeadersEvidence{H1: h2, H2: altH2}
+	ev := &types.ConflictingHeadersEvidence{H1: h2, H2: altH2}
 	assert.True(t, fullNode2.HasEvidence(ev))
 	assert.True(t, fullNode.HasEvidence(ev))
 }