Add new command line option to make replaying transactions easier

[Bronek]

High Level Overview of Change

Add new command line option trap_tx_hash to make replaying transactions easier

This new option can be used only if replay is also enabled. It takes a transaction hash from the ledger loaded for replay, and will cause a specific line to be hit in Transactor::operator(), right before apply().

Emit an error if:

• the new option is used without replay
• the supplied parameter cannot be parsed as transaction hash (i.e. uint256 in hex)
• the supplied transaction hash is not found on the ledger being replayed

Context of Change

While replaying specific ledger is relatively easy, things get more difficult if we want to debug a specific transaction within the ledger. There are several options, but all of them are a hassle. Why not just a new option to rippled to hit a very specific line of code, right before a specific transaction on the replayed ledger is being applied.

This change adds new virtual function std::optional<uint256> trapTxID() const to ripple::Application class. This new function is called inside Transactor::operator() to check if:

• trap transaction is set
• the currently processed transaction is a match

If both conditions are met, rippled will simply log Transaction trapped followed by a hash. The user can put a breakpoint at this line to break into the debugger.

Type of Change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] 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

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 71.3%. Comparing base (e3d1bb2) to head (add69ab).

:exclamation: Current head add69ab differs from pull request most recent head 79dff4b

Please upload reports for the commit 79dff4b to get more accurate results.

Additional details and impacted files

[](https://app.codecov.io/gh/XRPLF/rippled/pull/5027?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=XRPLF) ```diff @@ Coverage Diff @@ ## develop #5027 +/- ## ========================================= + Coverage 71.1% 71.3% +0.2% ========================================= Files 796 796 Lines 66997 66883 -114 Branches 10979 10867 -112 ========================================= + Hits 47635 47685 +50 + Misses 19362 19198 -164 ``` | [Files](https://app.codecov.io/gh/XRPLF/rippled/pull/5027?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=XRPLF) | Coverage Δ | | |---|---|---| | [src/ripple/app/main/Application.cpp](https://app.codecov.io/gh/XRPLF/rippled/pull/5027?src=pr&el=tree&filepath=src%2Fripple%2Fapp%2Fmain%2FApplication.cpp&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=XRPLF#diff-c3JjL3JpcHBsZS9hcHAvbWFpbi9BcHBsaWNhdGlvbi5jcHA=) | `65.9% <100.0%> (+2.9%)` | :arrow_up: | | [src/ripple/app/main/Application.h](https://app.codecov.io/gh/XRPLF/rippled/pull/5027?src=pr&el=tree&filepath=src%2Fripple%2Fapp%2Fmain%2FApplication.h&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=XRPLF#diff-c3JjL3JpcHBsZS9hcHAvbWFpbi9BcHBsaWNhdGlvbi5o) | `100.0% <ø> (ø)` | | | [src/ripple/app/main/Main.cpp](https://app.codecov.io/gh/XRPLF/rippled/pull/5027?src=pr&el=tree&filepath=src%2Fripple%2Fapp%2Fmain%2FMain.cpp&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=XRPLF#diff-c3JjL3JpcHBsZS9hcHAvbWFpbi9NYWluLmNwcA==) | `79.6% <100.0%> (+32.6%)` | :arrow_up: | | [src/ripple/app/tx/impl/Transactor.cpp](https://app.codecov.io/gh/XRPLF/rippled/pull/5027?src=pr&el=tree&filepath=src%2Fripple%2Fapp%2Ftx%2Fimpl%2FTransactor.cpp&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=XRPLF#diff-c3JjL3JpcHBsZS9hcHAvdHgvaW1wbC9UcmFuc2FjdG9yLmNwcA==) | `84.6% <100.0%> (+0.1%)` | :arrow_up: | | [src/ripple/core/Config.h](https://app.codecov.io/gh/XRPLF/rippled/pull/5027?src=pr&el=tree&filepath=src%2Fripple%2Fcore%2FConfig.h&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=XRPLF#diff-c3JjL3JpcHBsZS9jb3JlL0NvbmZpZy5o) | `77.8% <ø> (ø)` | | ... and [7 files with indirect coverage changes](https://app.codecov.io/gh/XRPLF/rippled/pull/5027/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=XRPLF) [](https://app.codecov.io/gh/XRPLF/rippled/pull/5027?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=XRPLF)

[Bronek]

I will try to add add unit test for this change, since apparently Application class is usable in unit tests.