Merge #13249: Make objects in range declarations immutable by default. Avoid unnecessary copying of objects in range declarations.

f34c8c466a0e514edac2e8683127b4176ad5d321 Make objects in range declarations immutable by default. Avoid unnecessary copying of objects in range declarations. (practicalswift)

Pull request description:

  Make objects in range declarations immutable by default.

  Rationale:
  * Immutable objects are easier to reason about.
  * Prevents accidental or hard-to-notice change of value.

Tree-SHA512: cad69d35f0cf8a938b848e65dd537c621d96fe3369be306b65ef0cd1baf6cc0a9f28bc230e1e383d810c555a6743d08cb6b2b0bd51856d4611f537a12e5abb8b

10 files changed, 22 insertions, 22 deletions

diff --git a/src/test/checkqueue_tests.cpp b/src/test/checkqueue_tests.cpp
index 39d0061c1c..2732598b4f 100644
--- a/src/test/checkqueue_tests.cpp
+++ b/src/test/checkqueue_tests.cpp
@@ -155,7 +155,7 @@ static void Correct_Queue_range(std::vector<size_t> range)
     }
     // Make vChecks here to save on malloc (this test can be slow...)
     std::vector<FakeCheckCheckCompletion> vChecks;
-    for (auto i : range) {
+    for (const size_t i : range) {
         size_t total = i;
         FakeCheckCheckCompletion::n_calls = 0;
         CCheckQueueControl<FakeCheckCheckCompletion> control(small_queue.get());
@@ -253,7 +253,7 @@ BOOST_AUTO_TEST_CASE(test_CheckQueue_Recovers_From_Failure)
     }
 
     for (auto times = 0; times < 10; ++times) {
-        for (bool end_fails : {true, false}) {
+        for (const bool end_fails : {true, false}) {
             CCheckQueueControl<FailingCheck> control(fail_queue.get());
             {
                 std::vector<FailingCheck> vChecks;
diff --git a/src/test/coins_tests.cpp b/src/test/coins_tests.cpp
index 57f4f7529f..6f4b5ecd26 100644
--- a/src/test/coins_tests.cpp
+++ b/src/test/coins_tests.cpp
@@ -736,7 +736,7 @@ static void CheckAddCoinBase(CAmount base_value, CAmount cache_value, CAmount mo
 template <typename... Args>
 static void CheckAddCoin(Args&&... args)
 {
-    for (CAmount base_value : {ABSENT, PRUNED, VALUE1})
+    for (const CAmount base_value : {ABSENT, PRUNED, VALUE1})
         CheckAddCoinBase(base_value, std::forward<Args>(args)...);
 }
 
@@ -848,10 +848,10 @@ BOOST_AUTO_TEST_CASE(ccoins_write)
     // they would be too repetitive (the parent cache is never updated in these
     // cases). The loop below covers these cases and makes sure the parent cache
     // is always left unchanged.
-    for (CAmount parent_value : {ABSENT, PRUNED, VALUE1})
-        for (CAmount child_value : {ABSENT, PRUNED, VALUE2})
-            for (char parent_flags : parent_value == ABSENT ? ABSENT_FLAGS : FLAGS)
-                for (char child_flags : child_value == ABSENT ? ABSENT_FLAGS : CLEAN_FLAGS)
+    for (const CAmount parent_value : {ABSENT, PRUNED, VALUE1})
+        for (const CAmount child_value : {ABSENT, PRUNED, VALUE2})
+            for (const char parent_flags : parent_value == ABSENT ? ABSENT_FLAGS : FLAGS)
+                for (const char child_flags : child_value == ABSENT ? ABSENT_FLAGS : CLEAN_FLAGS)
                     CheckWriteCoins(parent_value, child_value, parent_value, parent_flags, child_flags, parent_flags);
 }
 
diff --git a/src/test/cuckoocache_tests.cpp b/src/test/cuckoocache_tests.cpp
index ec7aba34ca..dbceb9d2e0 100644
--- a/src/test/cuckoocache_tests.cpp
+++ b/src/test/cuckoocache_tests.cpp
@@ -82,11 +82,11 @@ static double test_cache(size_t megabytes, double load)
      */
     std::vector<uint256> hashes_insert_copy = hashes;
     /** Do the insert */
-    for (uint256& h : hashes_insert_copy)
+    for (const uint256& h : hashes_insert_copy)
         set.insert(h);
     /** Count the hits */
     uint32_t count = 0;
-    for (uint256& h : hashes)
+    for (const uint256& h : hashes)
         count += set.contains(h, false);
     double hit_rate = ((double)count) / ((double)n_insert);
     return hit_rate;
@@ -323,7 +323,7 @@ static void test_cache_generations()
                 reads.push_back(inserts[i]);
             for (uint32_t i = n_insert - (n_insert / 4); i < n_insert; ++i)
                 reads.push_back(inserts[i]);
-            for (auto h : inserts)
+            for (const auto& h : inserts)
                 c.insert(h);
         }
     };
diff --git a/src/test/dbwrapper_tests.cpp b/src/test/dbwrapper_tests.cpp
index ffedead0e3..9957ac074b 100644
--- a/src/test/dbwrapper_tests.cpp
+++ b/src/test/dbwrapper_tests.cpp
@@ -26,7 +26,7 @@ BOOST_FIXTURE_TEST_SUITE(dbwrapper_tests, BasicTestingSetup)
 BOOST_AUTO_TEST_CASE(dbwrapper)
 {
     // Perform tests both obfuscated and non-obfuscated.
-    for (bool obfuscate : {false, true}) {
+    for (const bool obfuscate : {false, true}) {
         fs::path ph = SetDataDir(std::string("dbwrapper").append(obfuscate ? "_true" : "_false"));
         CDBWrapper dbw(ph, (1 << 20), true, false, obfuscate);
         char key = 'k';
@@ -46,7 +46,7 @@ BOOST_AUTO_TEST_CASE(dbwrapper)
 BOOST_AUTO_TEST_CASE(dbwrapper_batch)
 {
     // Perform tests both obfuscated and non-obfuscated.
-    for (bool obfuscate : {false, true}) {
+    for (const bool obfuscate : {false, true}) {
         fs::path ph = SetDataDir(std::string("dbwrapper_batch").append(obfuscate ? "_true" : "_false"));
         CDBWrapper dbw(ph, (1 << 20), true, false, obfuscate);
 
@@ -82,7 +82,7 @@ BOOST_AUTO_TEST_CASE(dbwrapper_batch)
 BOOST_AUTO_TEST_CASE(dbwrapper_iterator)
 {
     // Perform tests both obfuscated and non-obfuscated.
-    for (bool obfuscate : {false, true}) {
+    for (const bool obfuscate : {false, true}) {
         fs::path ph = SetDataDir(std::string("dbwrapper_iterator").append(obfuscate ? "_true" : "_false"));
         CDBWrapper dbw(ph, (1 << 20), true, false, obfuscate);
 
@@ -216,7 +216,7 @@ BOOST_AUTO_TEST_CASE(iterator_ordering)
         if (x & 1) BOOST_CHECK(dbw.Write(key, value));
     }
 
-    for (int seek_start : {0x00, 0x80}) {
+    for (const int seek_start : {0x00, 0x80}) {
         it->Seek((uint8_t)seek_start);
         for (unsigned int x=seek_start; x<255; ++x) {
             uint8_t key;
@@ -291,7 +291,7 @@ BOOST_AUTO_TEST_CASE(iterator_string_ordering)
     }
 
     std::unique_ptr<CDBIterator> it(const_cast<CDBWrapper&>(dbw).NewIterator());
-    for (int seek_start : {0, 5}) {
+    for (const int seek_start : {0, 5}) {
         snprintf(buf, sizeof(buf), "%d", seek_start);
         StringContentsSerializer seek_key(buf);
         it->Seek(seek_key);
diff --git a/src/test/getarg_tests.cpp b/src/test/getarg_tests.cpp
index eec7b38af7..7592330b10 100644
--- a/src/test/getarg_tests.cpp
+++ b/src/test/getarg_tests.cpp
@@ -24,7 +24,7 @@ static void ResetArgs(const std::string& strArg)
 
     // Convert to char*:
     std::vector<const char*> vecChar;
-    for (std::string& s : vecArg)
+    for (const std::string& s : vecArg)
         vecChar.push_back(s.c_str());
 
     std::string error;
diff --git a/src/test/key_io_tests.cpp b/src/test/key_io_tests.cpp
index 7e475ac610..a0c10d8ddd 100644
--- a/src/test/key_io_tests.cpp
+++ b/src/test/key_io_tests.cpp
@@ -136,7 +136,7 @@ BOOST_AUTO_TEST_CASE(key_io_invalid)
         std::string exp_base58string = test[0].get_str();
 
         // must be invalid as public and as private key
-        for (auto chain : { CBaseChainParams::MAIN, CBaseChainParams::TESTNET, CBaseChainParams::REGTEST }) {
+        for (const auto& chain : { CBaseChainParams::MAIN, CBaseChainParams::TESTNET, CBaseChainParams::REGTEST }) {
             SelectParams(chain);
             destination = DecodeDestination(exp_base58string);
             BOOST_CHECK_MESSAGE(!IsValidDestination(destination), "IsValid pubkey in mainnet:" + strTest);
diff --git a/src/test/skiplist_tests.cpp b/src/test/skiplist_tests.cpp
index bcd2a9c7b6..c0754618fb 100644
--- a/src/test/skiplist_tests.cpp
+++ b/src/test/skiplist_tests.cpp
@@ -146,7 +146,7 @@ BOOST_AUTO_TEST_CASE(findearliestatleast_test)
 BOOST_AUTO_TEST_CASE(findearliestatleast_edge_test)
 {
     std::list<CBlockIndex> blocks;
-    for (unsigned int timeMax : {100, 100, 100, 200, 200, 200, 300, 300, 300}) {
+    for (const unsigned int timeMax : {100, 100, 100, 200, 200, 200, 300, 300, 300}) {
         CBlockIndex* prev = blocks.empty() ? nullptr : &blocks.back();
         blocks.emplace_back();
         blocks.back().nHeight = prev ? prev->nHeight + 1 : 0;
diff --git a/src/test/test_bitcoin.cpp b/src/test/test_bitcoin.cpp
index a89bf785f1..0d7c9f0abf 100644
--- a/src/test/test_bitcoin.cpp
+++ b/src/test/test_bitcoin.cpp
@@ -29,7 +29,7 @@ void CConnmanTest::AddNode(CNode& node)
 void CConnmanTest::ClearNodes()
 {
     LOCK(g_connman->cs_vNodes);
-    for (CNode* node : g_connman->vNodes) {
+    for (const CNode* node : g_connman->vNodes) {
         delete node;
     }
     g_connman->vNodes.clear();
diff --git a/src/test/transaction_tests.cpp b/src/test/transaction_tests.cpp
index 33f0a83b7e..c527ad448c 100644
--- a/src/test/transaction_tests.cpp
+++ b/src/test/transaction_tests.cpp
@@ -65,7 +65,7 @@ unsigned int ParseScriptFlags(std::string strFlags)
     std::vector<std::string> words;
     boost::algorithm::split(words, strFlags, boost::algorithm::is_any_of(","));
 
-    for (std::string word : words)
+    for (const std::string& word : words)
     {
         if (!mapFlagNames.count(word))
             BOOST_ERROR("Bad test: unknown verification flag '" << word << "'");
diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp
index 8e2f5abe66..c74eb7531a 100644
--- a/src/test/util_tests.cpp
+++ b/src/test/util_tests.cpp
@@ -245,7 +245,7 @@ BOOST_AUTO_TEST_CASE(util_GetBoolArg)
     testArgs.ParseParameters(7, (char**)argv_test, error);
 
     // Each letter should be set.
-    for (char opt : "abcdef")
+    for (const char opt : "abcdef")
         BOOST_CHECK(testArgs.IsArgSet({'-', opt}) || !opt);
 
     // Nothing else should be in the map
@@ -394,7 +394,7 @@ BOOST_AUTO_TEST_CASE(util_ReadConfigStream)
                 && test_args.GetArg("-iii", "xxx") == "xxx"
                );
 
-    for (bool def : {false, true}) {
+    for (const bool def : {false, true}) {
         BOOST_CHECK(test_args.GetBoolArg("-a", def)
                      && test_args.GetBoolArg("-b", def)
                      && !test_args.GetBoolArg("-ccc", def)