fix: crash due to unitialized variable if no blocks has been mined yet

[knst]

Issue being fixed or feature implemented

Potential crash due to unitialized variable if no blocks has been mined yet

 ~/projects/dash/src/qt/dash-qt -regtest -datadir=/tmp/dd
ERROR: error detected null not_null detected at qt/masternodelist.cpp:167:0:updateDIP3List
std::terminate() called due unknown reason
   0#: (0x555DEA157622) stl_vector.h:768       - std::vector<unsigned long, std::allocator<unsigned long> >::operator=(std::vector<unsigned long, std::allocator<unsigned long> >&&)
   1#: (0x555DEA157622) stacktraces.cpp:747    - terminate_handler
   2#: (0x76A37E2B6E6C) <unknown-file>         - ???
   3#: (0x76A37E2B6ED7) <unknown-file>         - ???
   4#: (0x555DE9B43887) logging.h:156          - BCLog::Logger::Enabled() const
   5#: (0x555DE9B43887) logging.h:263          - LogPrintf_<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >
   6#: (0x555DE9B43887) assert.cpp:36          - gsl::details::terminate(nostd::source_location)
   7#: (0x555DE9A5314D) pointers.h:110         - gsl::not_null<CBlockIndex const* const>::not_null<void>(CBlockIndex const*, nostd::source_location)
   8#: (0x555DE9A5314D) masternodelist.cpp:167 - MasternodeList::updateDIP3List()
   9#: (0x555DE9A53678) masternodelist.cpp:147 - MasternodeList::updateDIP3ListScheduled()
  10#: (0x555DEAB42F5D) <unknown-file>         - ???
  11#: (0x555DEAB4B261) <unknown-file>         - ???
  12#: (0x555DEAB3D48B) <unknown-file>         - ???
  13#: (0x555DEADC1DF2) <unknown-file>         - ???
  14#: (0x555DEAB169F8) <unknown-file>         - ???
  15#: (0x555DEAB66F5D) <unknown-file>         - ???
  16#: (0x555DEAB64E84) <unknown-file>         - ???
  17#: (0x555DEACBCE22) <unknown-file>         - ???
  18#: (0x555DEAB14E56) <unknown-file>         - ???

What was done?

Initialized unitialized variable to nullptr, added check to nullptr.

How Has This Been Tested?

Should not crash

Breaking Changes

N/A

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests
• I have made corresponding changes to the documentation
• I have assigned this pull request to a milestone (for repository code-owners and collaborators only)

[coderabbitai]

Walkthrough

The pull request introduces two minor modifications across two different source files in a C++ project, likely related to a cryptocurrency or blockchain application. In src/qt/clientmodel.h, the mnListTip member variable of the ClientModel class is explicitly initialized to nullptr, ensuring a default null state when the object is created. In src/qt/masternodelist.cpp, the updateDIP3List method gains an early return guard clause that prevents processing if the pindex pointer is null, adding a defensive programming check to improve method robustness. These changes appear to be focused on improving code safety and preventing potential null pointer-related issues in the application's codebase.

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📜 Recent review details

Configuration used: CodeRabbit UI
Review profile: CHILL
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📥 Commits

Reviewing files that changed from the base of the PR and between 0972dfe and 5422b0a.

📒 Files selected for processing (2)

• src/qt/clientmodel.h (1 hunks)
• src/qt/masternodelist.cpp (1 hunks)

⏰ Context from checks skipped due to timeout of 90000ms (2)

• GitHub Check: Build Dependencies (linux64, x86_64-pc-linux-gnu)
• GitHub Check: Build Dependencies (arm-linux, arm-linux-gnueabihf)

🔇 Additional comments (2)

src/qt/clientmodel.h (1)

125-125: LGTM! Good defensive programming practice.

Explicitly initializing mnListTip to nullptr prevents potential crashes from accessing an uninitialized pointer. This change aligns with the PR's objective of fixing crashes due to uninitialized variables.

src/qt/masternodelist.cpp (1)

167-167: LGTM! Essential null check added.

The early return guard clause prevents null pointer dereference when no blocks have been mined yet. This defensive check works in conjunction with the nullptr initialization in ClientModel to prevent crashes.

✨ Finishing Touches

• 📝 Generate Docstrings (Beta)

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[UdjinM6]

utACK 5422b0a

[kwvg]

utACK 5422b0a