breaks down InvariantCheck to multiple classes

[Tapanito]

Summary

• Split InvariantCheck.h (733 lines) and InvariantCheck.cpp (3,483 lines) into 10 focused header/source pairs organized by domain under a new invariants/ subdirectory
• Extract the shared Privilege enum and hasPrivilege() function into a dedicated InvariantCheckPrivilege.h header so domain-specific files can reference them independently

Motivation

The invariant check system had grown into a single monolithic file pair containing 24 invariant checker classes. At 3,483 lines, InvariantCheck.cpp was a frequent source of merge conflicts and difficult to navigate. This refactoring improves maintainability and readability with zero behavioral changes.

File layout

include/xrpl/tx/invariants/
  InvariantCheck.h              # Core invariants + InvariantChecks tuple + sub-header aggregation
  InvariantCheckPrivilege.h     # Privilege enum, operator|, hasPrivilege() declaration
  AMMInvariant.h                # ValidAMM
  FreezeInvariant.h             # TransfersNotFrozen
  LoanInvariant.h               # ValidLoanBroker, ValidLoan
  MPTInvariant.h                # ValidMPTIssuance
  NFTInvariant.h                # ValidNFTokenPage, NFTokenCountTracking
  PermissionedDEXInvariant.h    # ValidPermissionedDEX
  PermissionedDomainInvariant.h # ValidPermissionedDomain
  VaultInvariant.h              # ValidVault

src/libxrpl/tx/invariants/
  InvariantCheck.cpp              # Core invariant impls + hasPrivilege() definition
  AMMInvariant.cpp                # ValidAMM + validBalances()
  FreezeInvariant.cpp             # TransfersNotFrozen (all methods)
  LoanInvariant.cpp               # ValidLoanBroker, ValidLoan
  MPTInvariant.cpp                # ValidMPTIssuance
  NFTInvariant.cpp                # ValidNFTokenPage, NFTokenCountTracking
  PermissionedDEXInvariant.cpp    # ValidPermissionedDEX
  PermissionedDomainInvariant.cpp # ValidPermissionedDomain
  VaultInvariant.cpp              # ValidVault

Design decisions

• InvariantCheck.h remains the single entry point: It #includes all sub-headers and still defines the InvariantChecks tuple and getInvariantChecks(). Consumers like ApplyContext.cpp only update the include path — no logic changes.
• InvariantCheckPrivilege.h: The Privilege enum and hasPrivilege() are used by 6 different invariant classes across separate translation units. The enum and constexpr operator| live in the header; hasPrivilege() is declared there but defined in InvariantCheck.cpp because it uses the transactions.macro X-macro which requires single-TU compilation.
• No CMake changes needed: add_module(xrpl tx) uses GLOB_RECURSE which automatically discovers files in subdirectories.

Next Steps

• Breakdown Invariants_test into separate classes, see Refactors vault invariant tests to test all asset types. #6269 for an example.
• Breakdown each top level invariant into per-transaction invariants. For example, VaultInvariant would become:
  • VaultInvariant < ---- Holds base invariants that must hold true for the object
  • VaultCreateInvariant < ----- Holds invariants associated with the VaultCreate transaction
  • VaultDeleteInvariant < ----- Holds invariants associated with the VaultCreate transaction
    Vault...Invariant

High Level Overview of Change

Context of Change

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor (non-breaking change that only restructures code)
• Performance (increase or change in throughput and/or latency)
• Tests (you added tests for code that already exists, or your new feature included in this PR)
• Documentation update
• Chore (no impact to binary, e.g. .gitignore, formatting, dropping support for older tooling)
• Release

API Impact

• Public API: New feature (new methods and/or new fields)
• Public API: Breaking change (in general, breaking changes should only impact the next api_version)
• libxrpl change (any change that may affect libxrpl or dependents of libxrpl)
• Peer protocol change (must be backward compatible or bump the peer protocol version)

[codecov]

Codecov Report

❌ Patch coverage is 93.07642% with 106 lines in your changes missing coverage. Please review.
✅ Project coverage is 79.8%. Comparing base (404f35d) to head (918bf5e).
⚠️ Report is 2 commits behind head on develop.

Files with missing lines	Patch %	Lines
src/libxrpl/tx/invariants/MPTInvariant.cpp	73.3%	24 Missing ⚠️
src/libxrpl/tx/invariants/NFTInvariant.cpp	79.5%	24 Missing ⚠️
src/libxrpl/tx/invariants/LoanInvariant.cpp	82.5%	20 Missing ⚠️
src/libxrpl/tx/invariants/InvariantCheck.cpp	95.8%	17 Missing ⚠️
src/libxrpl/tx/invariants/VaultInvariant.cpp	98.2%	9 Missing ⚠️
src/libxrpl/tx/invariants/FreezeInvariant.cpp	91.2%	7 Missing ⚠️
src/libxrpl/tx/invariants/AMMInvariant.cpp	95.3%	5 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #6440   +/-   ##
=======================================
  Coverage     79.8%   79.8%           
=======================================
  Files          848     858   +10     
  Lines        67757   67757           
  Branches      7558    7550    -8     
=======================================
+ Hits         54074   54077    +3     
+ Misses       13683   13680    -3     

Files with missing lines	Coverage Δ
include/xrpl/tx/invariants/AMMInvariant.h	100.0% <100.0%> (ø)
include/xrpl/tx/invariants/InvariantCheck.h	100.0% <100.0%> (ø)
...clude/xrpl/tx/invariants/InvariantCheckPrivilege.h	100.0% <100.0%> (ø)
src/libxrpl/tx/ApplyContext.cpp	100.0% <ø> (ø)
...libxrpl/tx/invariants/PermissionedDEXInvariant.cpp	100.0% <100.0%> (ø)
...xrpl/tx/invariants/PermissionedDomainInvariant.cpp	100.0% <100.0%> (ø)
...ctors/PermissionedDomain/PermissionedDomainSet.cpp	100.0% <ø> (ø)
src/libxrpl/tx/invariants/AMMInvariant.cpp	95.3% <95.3%> (ø)
src/libxrpl/tx/invariants/FreezeInvariant.cpp	91.2% <91.2%> (ø)
src/libxrpl/tx/invariants/VaultInvariant.cpp	98.2% <98.2%> (ø)
... and 4 more

... and 5 files with indirect coverage changes

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[godexsoft]

I like this new structure. We should consider adding a namespace like 'invariants' for all of this (could be done in a separate pr if there is interest).

To fix pre-commit you may want to setup pre-commit hooks so that clang-format automatically fixes code when you commit/push.

[kuznetsss]

👍

[Tapanito]

I like this new structure. We should consider adding a namespace like 'invariants' for all of this (could be done in a separate pr if there is interest).

To fix pre-commit you may want to setup pre-commit hooks so that clang-format automatically fixes code when you commit/push.

Thanks @godexsoft ! I'm not sure why my local formatter keeps making these changes... I configured pre-commit