Chore: Eliminate BlockEvaluator.Transaction

[jannotti]

The existence of a public BlockEvaluator.Transaction perpetuates the myth that it's reasonable to evaluate transactions one at a time. No "real" code used this method, only tests, which actually meant "construct a one element Group and evaluate it. To eliminate it, and keep the test callers from looking cluttered, TransactionGroup() was made variadic, and WithAD() was added as a convenient way to construct a SignedTransactionWithAD from SignedTransaction.

This means that called to TransactionGroup(x) become TransactionGroup(x...), but note that this does not allocate or copy. Go Spec says this about variadic functions:

If the final argument is assignable to a slice type []T and is followed by ..., it is passed unchanged as the value for a ...T parameter. In this case no new slice is created.

Given the slice s and call

s := []string{"James", "Jasmine"}
Greeting("goodbye:", s...)
within Greeting, who will have the same value as s with the same underlying array.

TestTransaction was also needlessly exported. It's now testTransaction. (It was the conflicting meaning for TestTransaction and Transaction that really bugged me - TestTransaction was in internal method used by TestTransactionGroup, but Transaction was a wrapper around TransactionGroup that constructed a singleton group and called it.)

Summary

Test Plan

[codecov]

Codecov Report

❌ Patch coverage is 68.42105% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 47.67%. Comparing base (3780647) to head (bf4a585).
⚠️ Report is 1 commits behind head on master.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
data/transactions/signedtxn.go	50.00%	4 Missing ⚠️
ledger/eval/evalindexer.go	0.00%	1 Missing ⚠️
ledger/simulation/testing/utils.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6515      +/-   ##
==========================================
- Coverage   47.86%   47.67%   -0.19%     
==========================================
  Files         662      655       -7     
  Lines       87936    87849      -87     
==========================================
- Hits        42087    41881     -206     
- Misses      43085    43188     +103     
- Partials     2764     2780      +16     

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[Copilot]

Pull request overview

This PR removes the BlockEvaluator.Transaction method to discourage evaluating transactions individually rather than as groups. The method is replaced by making TransactionGroup variadic and adding a WithAD() helper method to SignedTxn for convenient conversion to SignedTxnWithAD. Additionally, the internal test helper TestTransaction is renamed to testTransaction to reflect its private scope.

• Changed TransactionGroup from accepting a slice to accepting variadic arguments
• Added WithAD() method to SignedTxn for creating SignedTxnWithAD with empty ApplyData
• Replaced all Transaction() calls with TransactionGroup() using variadic syntax

Reviewed changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tools/block-generator/generator/generator_ledger.go	Updated to use variadic TransactionGroup with spread operator
ledger/txnbench_test.go	Replaced Transaction call with TransactionGroup using WithAD() helper
ledger/simulation/testing/utils.go	Replaced Transaction call with TransactionGroup using WithAD() helper
ledger/simulation/simulator.go	Updated to use variadic TransactionGroup with spread operator
ledger/simple_test.go	Replaced Transaction calls with TransactionGroup using WithAD() and spread operator
ledger/ledger_perf_test.go	Replaced Transaction calls with TransactionGroup using WithAD() helper
ledger/fullblock_perf_test.go	Replaced Transaction call with TransactionGroup using WithAD() helper
ledger/evalbench_test.go	Replaced Transaction calls with TransactionGroup using WithAD() helper
ledger/eval_simple_test.go	Replaced multiple Transaction calls with TransactionGroup using WithAD() and spread operator
ledger/eval/txntracer_test.go	Updated to use variadic TransactionGroup and simplified single-transaction group construction
ledger/eval/prefetcher/prefetcher_alignment_test.go	Updated to use variadic TransactionGroup with spread operator
ledger/eval/evalindexer.go	Updated to use variadic TransactionGroup with spread operator
ledger/eval/eval_test.go	Replaced Transaction calls with TransactionGroup using WithAD() and updated to variadic syntax
ledger/eval/eval.go	Removed Transaction method, made TransactionGroup variadic, and renamed TestTransaction to testTransaction
data/transactions/signedtxn.go	Added WithAD() helper method to create SignedTxnWithAD from SignedTxn
data/pools/transactionPool_test.go	Replaced Transaction calls with TransactionGroup using WithAD() helper
data/pools/transactionPool.go	Updated BlockEvaluator interface to use variadic TransactionGroup and removed Transaction method

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[Copilot]

Pull request overview

Copilot reviewed 28 out of 28 changed files in this pull request and generated no new comments.

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[algorandskiy]

I did some random sampling old vs new allocs (-benchmem) - no changes.