fix: end exclusive parse namespace end share range (backport #2208) (#…

…3491)

This is an automatic backport of pull request #2208 done by
[Mergify](https://mergify.com).

Motivated by this [Slack
thread](https://celestia-team.slack.com/archives/C03MP6DPLAD/p1715891011859219).
It seems like we forgot to backport this fix. cc: @rach-id

---------

Co-authored-by: CHAMI Rachid <[email protected]>
Co-authored-by: Rootul Patel <[email protected]>

pkg/proof/proof_test.go

@@ -242,3 +242,35 @@ func TestQueryTxInclusionProofRejectsNegativeValues(t *testing.T) {
 		t.Fatal("no rawProof expected")
 	}
 }
+
+// TestAllSharesInclusionProof creates a proof for all shares in the data
+// square. Since we can't prove multiple namespaces at the moment, all the
+// shares use the same namespace.
+func TestAllSharesInclusionProof(t *testing.T) {
+	txs := testfactory.GenerateRandomTxs(243, 500)
+
+	dataSquare, err := square.Construct(txs.ToSliceOfBytes(), appconsts.LatestVersion, 128)
+	require.NoError(t, err)
+	assert.Equal(t, 256, len(dataSquare))
+
+	// erasure the data square which we use to create the data root.
+	eds, err := da.ExtendShares(shares.ToBytes(dataSquare))
+	require.NoError(t, err)
+
+	// create the new data root by creating the data availability header (merkle
+	// roots of each row and col of the erasure data).
+	dah, err := da.NewDataAvailabilityHeader(eds)
+	require.NoError(t, err)
+	dataRoot := dah.Hash()
+
+	actualNamespace, err := proof.ParseNamespace(dataSquare, 0, 256)
+	require.NoError(t, err)
+	require.Equal(t, appns.TxNamespace, actualNamespace)
+	proof, err := proof.NewShareInclusionProof(
+		dataSquare,
+		appns.TxNamespace,
+		shares.NewRange(0, 256),
+	)
+	require.NoError(t, err)
+	assert.NoError(t, proof.Validate(dataRoot))
+}

pkg/proof/querier.go

@@ -136,7 +136,7 @@ func ParseNamespace(rawShares []shares.Share, startShare, endShare int) (appns.N
 		return appns.Namespace{}, fmt.Errorf("end share %d cannot be lower than starting share %d", endShare, startShare)
 	}
 
-	if endShare >= len(rawShares) {
+	if endShare > len(rawShares) {
 		return appns.Namespace{}, fmt.Errorf("end share %d is higher than block shares %d", endShare, len(rawShares))
 	}