Merge bitcoin/bitcoin#25707: refactor: Make const references to avoid unnecessarily copying objects and enable two clang-tidy checks

ae7ae36d311a869b3bda41d29dc0e47fade77d28 tidy: Enable two clang-tidy checks (Aurèle Oulès)
081b0e53e3adca7ea57d23e5fcd9db4b86415a72 refactor: Make const refs vars where applicable (Aurèle Oulès)

Pull request description:

  I added const references to some variables to avoid unnecessarily copying objects.

  Also added two clang-tidy checks : [performance-for-range-copy](https://releases.llvm.org/11.1.0/tools/clang/tools/extra/docs/clang-tidy/checks/performance-for-range-copy.html) and [performance-unnecessary-copy-initialization](https://releases.llvm.org/12.0.0/tools/clang/tools/extra/docs/clang-tidy/checks/performance-unnecessary-copy-initialization.html).

ACKs for top commit:
  vasild:
    ACK ae7ae36d311a869b3bda41d29dc0e47fade77d28
  MarcoFalke:
    review ACK ae7ae36d311a869b3bda41d29dc0e47fade77d28

Tree-SHA512: f6ac6b0cd0eee1e0c34d2f186484bc0f7ec6071451cccb33fa88a67d93d92b304e2fac378b88f087e94657745bca4e966dbc443759587400eb01b1f3061fde8c

7 files changed, 13 insertions, 13 deletions

diff --git a/src/test/base58_tests.cpp b/src/test/base58_tests.cpp
index 00f32ddcee..249f89ae2f 100644
--- a/src/test/base58_tests.cpp
+++ b/src/test/base58_tests.cpp
@@ -25,7 +25,7 @@ BOOST_AUTO_TEST_CASE(base58_EncodeBase58)
 {
     UniValue tests = read_json(std::string(json_tests::base58_encode_decode, json_tests::base58_encode_decode + sizeof(json_tests::base58_encode_decode)));
     for (unsigned int idx = 0; idx < tests.size(); idx++) {
-        UniValue test = tests[idx];
+        const UniValue& test = tests[idx];
         std::string strTest = test.write();
         if (test.size() < 2) // Allow for extra stuff (useful for comments)
         {
@@ -47,7 +47,7 @@ BOOST_AUTO_TEST_CASE(base58_DecodeBase58)
     std::vector<unsigned char> result;
 
     for (unsigned int idx = 0; idx < tests.size(); idx++) {
-        UniValue test = tests[idx];
+        const UniValue& test = tests[idx];
         std::string strTest = test.write();
         if (test.size() < 2) // Allow for extra stuff (useful for comments)
         {
diff --git a/src/test/blockfilter_tests.cpp b/src/test/blockfilter_tests.cpp
index 178757e7b4..0831188327 100644
--- a/src/test/blockfilter_tests.cpp
+++ b/src/test/blockfilter_tests.cpp
@@ -137,7 +137,7 @@ BOOST_AUTO_TEST_CASE(blockfilters_json_test)
 
     const UniValue& tests = json.get_array();
     for (unsigned int i = 0; i < tests.size(); i++) {
-        UniValue test = tests[i];
+        const UniValue& test = tests[i];
         std::string strTest = test.write();
 
         if (test.size() == 1) {
diff --git a/src/test/key_io_tests.cpp b/src/test/key_io_tests.cpp
index e70b8b3dfd..1eac68de14 100644
--- a/src/test/key_io_tests.cpp
+++ b/src/test/key_io_tests.cpp
@@ -28,7 +28,7 @@ BOOST_AUTO_TEST_CASE(key_io_valid_parse)
     SelectParams(CBaseChainParams::MAIN);
 
     for (unsigned int idx = 0; idx < tests.size(); idx++) {
-        UniValue test = tests[idx];
+        const UniValue& test = tests[idx];
         std::string strTest = test.write();
         if (test.size() < 3) { // Allow for extra stuff (useful for comments)
             BOOST_ERROR("Bad test: " << strTest);
@@ -86,7 +86,7 @@ BOOST_AUTO_TEST_CASE(key_io_valid_gen)
     UniValue tests = read_json(std::string(json_tests::key_io_valid, json_tests::key_io_valid + sizeof(json_tests::key_io_valid)));
 
     for (unsigned int idx = 0; idx < tests.size(); idx++) {
-        UniValue test = tests[idx];
+        const UniValue& test = tests[idx];
         std::string strTest = test.write();
         if (test.size() < 3) // Allow for extra stuff (useful for comments)
         {
@@ -126,7 +126,7 @@ BOOST_AUTO_TEST_CASE(key_io_invalid)
     CTxDestination destination;
 
     for (unsigned int idx = 0; idx < tests.size(); idx++) {
-        UniValue test = tests[idx];
+        const UniValue& test = tests[idx];
         std::string strTest = test.write();
         if (test.size() < 1) // Allow for extra stuff (useful for comments)
         {
diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
index 9e7a376d6b..935194057c 100644
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -942,7 +942,7 @@ BOOST_AUTO_TEST_CASE(script_json_test)
     UniValue tests = read_json(std::string(json_tests::script_tests, json_tests::script_tests + sizeof(json_tests::script_tests)));
 
     for (unsigned int idx = 0; idx < tests.size(); idx++) {
-        UniValue test = tests[idx];
+        const UniValue& test = tests[idx];
         std::string strTest = test.write();
         CScriptWitness witness;
         CAmount nValue = 0;
diff --git a/src/test/sighash_tests.cpp b/src/test/sighash_tests.cpp
index 7376f2ff5c..514798d8fa 100644
--- a/src/test/sighash_tests.cpp
+++ b/src/test/sighash_tests.cpp
@@ -165,7 +165,7 @@ BOOST_AUTO_TEST_CASE(sighash_from_data)
     UniValue tests = read_json(std::string(json_tests::sighash, json_tests::sighash + sizeof(json_tests::sighash)));
 
     for (unsigned int idx = 0; idx < tests.size(); idx++) {
-        UniValue test = tests[idx];
+        const UniValue& test = tests[idx];
         std::string strTest = test.write();
         if (test.size() < 1) // Allow for extra stuff (useful for comments)
         {
diff --git a/src/test/transaction_tests.cpp b/src/test/transaction_tests.cpp
index cd6bf11327..952598f745 100644
--- a/src/test/transaction_tests.cpp
+++ b/src/test/transaction_tests.cpp
@@ -194,7 +194,7 @@ BOOST_AUTO_TEST_CASE(tx_valid)
     UniValue tests = read_json(std::string(json_tests::tx_valid, json_tests::tx_valid + sizeof(json_tests::tx_valid)));
 
     for (unsigned int idx = 0; idx < tests.size(); idx++) {
-        UniValue test = tests[idx];
+        const UniValue& test = tests[idx];
         std::string strTest = test.write();
         if (test[0].isArray())
         {
@@ -214,7 +214,7 @@ BOOST_AUTO_TEST_CASE(tx_valid)
                     fValid = false;
                     break;
                 }
-                UniValue vinput = input.get_array();
+                const UniValue& vinput = input.get_array();
                 if (vinput.size() < 3 || vinput.size() > 4)
                 {
                     fValid = false;
@@ -282,7 +282,7 @@ BOOST_AUTO_TEST_CASE(tx_invalid)
     UniValue tests = read_json(std::string(json_tests::tx_invalid, json_tests::tx_invalid + sizeof(json_tests::tx_invalid)));
 
     for (unsigned int idx = 0; idx < tests.size(); idx++) {
-        UniValue test = tests[idx];
+        const UniValue& test = tests[idx];
         std::string strTest = test.write();
         if (test[0].isArray())
         {
@@ -302,7 +302,7 @@ BOOST_AUTO_TEST_CASE(tx_invalid)
                     fValid = false;
                     break;
                 }
-                UniValue vinput = input.get_array();
+                const UniValue& vinput = input.get_array();
                 if (vinput.size() < 3 || vinput.size() > 4)
                 {
                     fValid = false;
diff --git a/src/test/validation_block_tests.cpp b/src/test/validation_block_tests.cpp
index 7a82e1a736..1c5ca18759 100644
--- a/src/test/validation_block_tests.cpp
+++ b/src/test/validation_block_tests.cpp
@@ -183,7 +183,7 @@ BOOST_AUTO_TEST_CASE(processnewblock_signals_ordering)
             }
 
             // to make sure that eventually we process the full chain - do it here
-            for (auto block : blocks) {
+            for (const auto& block : blocks) {
                 if (block->vtx.size() == 1) {
                     bool processed = Assert(m_node.chainman)->ProcessNewBlock(block, true, &ignored);
                     assert(processed);