SERVER-90594 Add `bugprone-too-small-loop-variable` to clang-tidy (#22286)

GitOrigin-RevId: cf54d27c154af8d269c2f9159466d1ffb6b67e91

.clang-tidy.in

@@ -24,6 +24,7 @@ Checks:          '-*,
                   bugprone-suspicious-string-compare,
                   bugprone-swapped-arguments,
                   bugprone-terminating-continue,
+                  bugprone-too-small-loop-variable,
                   bugprone-undelegated-constructor,
                   bugprone-unused-raii,
                   bugprone-unused-return-value,

src/mongo/bson/util/bsoncolumn_test.cpp

@@ -258,7 +258,7 @@ public:
     }
 
     static uint64_t deltaDouble(BSONElement val, BSONElement prev, double scaleFactor) {
-        uint8_t scaleIndex = 0;
+        size_t scaleIndex = 0;
         for (; scaleIndex < Simple8bTypeUtil::kScaleMultiplier.size(); ++scaleIndex) {
             if (Simple8bTypeUtil::kScaleMultiplier[scaleIndex] == scaleFactor)
                 break;

src/mongo/bson/util/simple8b_type_util.cpp

@@ -105,7 +105,7 @@ boost::optional<uint8_t> Simple8bTypeUtil::calculateDecimalShiftMultiplier(doubl
     }
     // Try multiplying by selected powers of 10 until we do not have any decimal digits. If we
     // always have leftover digits, return none.
-    for (uint8_t i = 0; i < kScaleMultiplier.size(); ++i) {
+    for (size_t i = 0; i < kScaleMultiplier.size(); ++i) {
         double scaleMultiplier = kScaleMultiplier[i];
         double valTimesMultiplier = val * scaleMultiplier;
         // Checks for both overflows

src/mongo/db/field_ref.cpp

@@ -329,7 +329,7 @@ StringData FieldRef::dottedSubstring(FieldIndex startPart, FieldIndex endPart) c
 bool FieldRef::equalsDottedField(StringData other) const {
     StringData rest = other;
 
-    for (FieldIndex i = 0; i < _parts.size(); i++) {
+    for (size_t i = 0; i < _parts.size(); i++) {
         StringData part = getPart(i);
 
         if (!rest.startsWith(part))

src/mongo/db/update/update_object_node.cpp

@@ -159,7 +159,7 @@ void applyChild(const UpdateNode& child,
     // If the child is an internal node, it may have created 'pathToCreate' and moved 'pathToCreate'
     // to the end of 'pathTaken'. We should advance 'element' to the end of 'pathTaken'.
     if (updateNodeApplyParams->pathTaken->size() > pathTakenSizeBefore) {
-        for (auto i = pathTakenSizeBefore; i < updateNodeApplyParams->pathTaken->size(); ++i) {
+        for (size_t i = pathTakenSizeBefore; i < updateNodeApplyParams->pathTaken->size(); ++i) {
             applyParams->element = getChild(
                 applyParams->element, updateNodeApplyParams->pathTaken->fieldRef().getPart(i));
             invariant(applyParams->element.ok());