Dereferencing of the invalid iterator 'iter' might take place.

[samthemadrabbit]

PVS-Studio shows possible errors on lines 4704, 4920 and 5208 of amalgamated source file jsoncpp.cpp (version 1.8.1) for "Dereferencing of the invalid iterator 'iter' might take place."

[cdunn2001]

Post a pull-request?

[BillyDonahue]

I can't replicate this.
Can you identify the source locations or paste the lines?
I'm checking out branch 1.8.1 and my amalgamated dist/jsoncpp.cpp doesn't have any 'iter' on those line numbers.

[samthemadrabbit]

These are in methods:

void StyledWriter::writeCommentBeforeValue(const Value& root) {
  if (!root.hasComment(commentBefore))
    return;

  document_ += "\n";
  writeIndent();
  const JSONCPP_STRING& comment = root.getComment(commentBefore);
  JSONCPP_STRING::const_iterator iter = comment.begin();
  while (iter != comment.end()) {
    document_ += *iter;
    if (*iter == '\n' &&
       (iter != comment.end() && *(iter + 1) == '/'))
      writeIndent();
    ++iter;
  }

void StyledStreamWriter::writeCommentBeforeValue(const Value& root) {
  if (!root.hasComment(commentBefore))
    return;

  if (!indented_) writeIndent();
  const JSONCPP_STRING& comment = root.getComment(commentBefore);
  JSONCPP_STRING::const_iterator iter = comment.begin();
  while (iter != comment.end()) {
    *document_ << *iter;
    if (*iter == '\n' &&
       (iter != comment.end() && *(iter + 1) == '/'))
      // writeIndent();  // would include newline
      *document_ << indentString_;
    ++iter;
  }
  indented_ = false;
}

void BuiltStyledStreamWriter::writeCommentBeforeValue(Value const& root) {
  if (cs_ == CommentStyle::None) return;
  if (!root.hasComment(commentBefore))
    return;

  if (!indented_) writeIndent();
  const JSONCPP_STRING& comment = root.getComment(commentBefore);
  JSONCPP_STRING::const_iterator iter = comment.begin();
  while (iter != comment.end()) {
    *sout_ << *iter;
    if (*iter == '\n' &&
       (iter != comment.end() && *(iter + 1) == '/'))
      // writeIndent();  // would write extra newline
      *sout_ << indentString_;
    ++iter;
  }
  indented_ = false;
}

All warnings are shown on the condition

if (*iter == '\n' &&
       (iter != comment.end() && *(iter + 1) == '/'))

[cdunn2001]

That's theoretically possible, but only if the comment is illegal. Anyway, looks easy to prevent. Fixing...