feat: add backwards compatibility for `Response::traces` by Wodann · Pull Request #1301 · NomicFoundation/edr

Wodann · 2026-02-19T17:54:52Z

Resolves #1288.

This reintroduces the Response::traces getter function to maintain support for Hardhat 2's EthereumJS VM interface.

I tested this using the help of Claude:

Hardhat Plugin Compatibility Report — EDR Tracing Back-Compat

Date: 2026-02-20
EDR branch: feat/tracing-back-compat
Hardhat branch: hh2/tracing-unification

Overview

This report validates that the new EDR trace format (unified tracing architecture)
is backward-compatible with the existing Hardhat v2 plugin ecosystem. Testing was
performed at three levels:

Plugin test suites — each plugin's own tests run against local Hardhat+EDR
Third-party project tests — real-world projects using stock plugins
Third-party projects with linked plugins — full local stack (EDR + Hardhat + plugins)

Critical Finding: `includeCallTraces` Default

During testing, solidity-coverage's test suite revealed that Response::traces()
returned empty arrays because include_call_traces defaults to IncludeTraces::None
in the new architecture. This was fixed in Hardhat commit c46cf5b by setting
includeCallTraces: IncludeTraces.All in the provider's observability config.

Plugin Test Suite Results

hardhat-gas-reporter v2.3.0

Category	Pass	Fail	Notes
Unit tests	16	5	Failures: missing API keys (CMC/Etherscan)
Integration tests	30	7	Failures: missing API keys + Alchemy token

Trace-format failures: 0. All gas measurement and reporting functionality works.

solidity-coverage v0.8.17

Category	Pass	Fail	Notes
Unit tests (before fix)	60	75	All failures: 0% coverage
Unit tests (after fix)	135	0	All recovered
Integration tests (before fix)	19	23	All failures: 0% coverage
Integration tests (after fix)	41	1	1 pre-existing (block gas limit)

Trace-format failures after fix: 0.

hardhat-tracer v3.4.0

Category	Pass	Fail	Notes
Tests	9	4	Failures: 2 missing Alchemy key, 2 stdin bug

Trace-format failures: 0. All trace-exercising tests pass (CALLs, STATICCALLs,
DELEGATECALLs, opcodes, debug_traceTransaction).

Third-Party Project Results (with linked plugins)

Seaport (best result — full validation)

Mode	Pass	Extra
Tests	402	--
Gas Reporter	402	Real gas data (e.g., ConduitController.createConduit avg 223,418)
Coverage	402	13.79% stmts overall; 95% for zones

OpenZeppelin Contracts v5.5.0

Mode	Pass	Fail	Extra
Tests (ERC20)	126	0	--
Gas Reporter	126	0	Real gas data (approve avg 44,656; transfer avg 40,133)
Coverage	--	--	Compilation fails (instrumentation bloat, not trace-related)

NexusMutual

Mode	Pass	Fail	Extra
Tests	0	2	Gas cap issue (30M > 16.7M cap)
Gas Reporter	0	2	Same gas cap issue
Coverage	2	0	Non-zero data (Pool.sol: 29.77% stmts)

Additional projects tested (stock plugins, local Hardhat+EDR)

Project	Tests	Gas Reporter	Coverage	Trace Errors
Rocket Pool	Subset pass	Works	Works	None
Synthetix	99/99 pass	Works	N/A	None
Safe Contracts	0/58 (gas cap)	N/A	N/A	None

Non-Trace Issues Found

EIP-7825 gas cap (Safe, NexusMutual): Transactions exceeding 16,777,216 gas
fail. This is a hardfork behavioral change, not a trace issue.
Synthetix function overloading: Pre-existing EDR limitation. Unrelated to traces.
OpenZeppelin coverage compilation: solidity-coverage instrumentation bloat
causes compilation failure on the full OZ codebase. Not trace-related.

Risk Assessment

Risk of trace format changes breaking existing Hardhat plugins: LOW

With the includeCallTraces: IncludeTraces.All fix in place, the backward-compatibility
layer in EDR (Response::traces()) combined with the Hardhat adapter successfully
preserves the expected trace format for all tested plugins:

hardhat-gas-reporter: Fully functional
solidity-coverage: Fully functional (after fix)
hardhat-tracer: Fully functional

changeset-bot · 2026-02-19T17:54:59Z

🦋 Changeset detected

Latest commit: 369dc66

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@nomicfoundation/edr	Minor

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Click here if you're a maintainer who wants to add another changeset to this PR

Copilot

Pull request overview

This PR reintroduces backwards compatibility for the Response::traces getter to support Hardhat 2's EthereumJS VM interface. The implementation converts the new CallTraceArena format back to the flat trace format that Hardhat 2 expects.

Changes:

Adds Response::traces() method that converts CallTraceArena to flat trace format compatible with Hardhat 2
Removes edr_tracing dependency from multiple crates
Deletes nested_tracer.rs and related code that are no longer needed
Re-enables verbose tracing tests for Hardhat 2 compatibility

Reviewed changes

Copilot reviewed 22 out of 25 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
`crates/edr_napi/src/trace.rs`	Implements conversion from `CallTraceArena` to flat trace format with Hardhat 2 compatibility quirks
`crates/edr_napi/src/provider/response.rs`	Adds `traces()` method to Response
`crates/edr_provider/src/observability.rs`	Updates tracing configuration to capture full stack snapshots
`patches/hardhat@2.28.4.patch`	Updates Hardhat 2 integration to use new trace format
`crates/edr_napi/test/provider.ts`	Re-enables verbose tracing tests
Multiple Cargo.toml files	Removes `edr_tracing` dependency
`crates/edr_solidity/src/nested_tracer.rs`	Deleted - no longer needed

Files not reviewed (1)

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Copilot · 2026-02-19T17:57:38Z

+                    .get(call_id)
+                    .expect("child index should be valid");
+
+                if matches!(step.op, OpCode::CREATE | OpCode::CREATE2) || !should_skip_call(trace) {


The should_skip_call function is called with the wrong trace parameter. On line 230, it's called with trace (the parent trace), but it should be called with node.trace (the child trace) to check whether the child call should be skipped.

The function checks if a call has no steps and immediately reverts, which is a property of the child trace, not the parent trace.

Suggested change

if matches!(step.op, OpCode::CREATE | OpCode::CREATE2) || !should_skip_call(trace) {

if matches!(step.op, OpCode::CREATE | OpCode::CREATE2) || !should_skip_call(&node.trace) {

I believe this is a correct observation from Copilot.

Addresssed by df5f2c5.

Copilot · 2026-02-19T17:57:39Z

        let tracing_config = if config.verbose_raw_tracing {
            TracingInspectorConfig::all()
        } else {
-            TracingInspectorConfig::default_parity().set_steps(true)
+            TracingInspectorConfig::default_parity()
+                .set_steps(true)
+                .set_stack_snapshots(StackSnapshotType::Full)


The StackSnapshotType::Full configuration is set regardless of verbose mode. This means that the full stack will always be captured in the tracing inspector, even when verbose tracing is disabled.

However, the actual filtering to return only the top of the stack happens in the conversion function raw_trace_from_call_trace_arena based on the verbose parameter. This creates an inconsistency where:

The inspector always captures full stack (performance cost)

The conversion then throws away most of the data when verbose=false

Consider setting StackSnapshotType based on verbose_raw_tracing to avoid unnecessary data collection and improve performance.

codecov · 2026-02-19T18:32:28Z

Codecov Report

❌ Patch coverage is 11.48649% with 131 lines in your changes missing coverage. Please review.
✅ Project coverage is 73.94%. Comparing base (28b7b04) to head (d203b12).

Files with missing lines	Patch %	Lines
crates/edr_napi/src/trace.rs	0.00%	122 Missing ⚠️
crates/edr_napi/src/provider/response.rs	0.00%	7 Missing ⚠️
crates/edr_napi_core/src/spec.rs	71.42%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1301      +/-   ##
==========================================
+ Coverage   73.72%   73.94%   +0.21%     
==========================================
  Files         445      444       -1     
  Lines       75876    75662     -214     
  Branches    75876    75662     -214     
==========================================
+ Hits        55942    55945       +3     
+ Misses      17882    17666     -216     
+ Partials     2052     2051       -1

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popescuoctavian

Overall looks good, but I believe there is an issue which Copilot pointed out and a small simplification.

popescuoctavian · 2026-02-23T14:21:31Z

+                    .get(call_id)
+                    .expect("child index should be valid");
+
+                if matches!(step.op, OpCode::CREATE | OpCode::CREATE2) || !should_skip_call(trace) {


I believe this is a correct observation from Copilot.

popescuoctavian · 2026-02-23T14:28:42Z

+    if trace.steps.is_empty()
+        && let Some(status) = trace.status
+        && matches!(status, return_revert!())
+    {
+        true
+    } else {
+        false
    }


This can be simplified to return the condition

Addressed by df5f2c5.

popescuoctavian

There is significant performance regression seen in the benchmarks -- up to 2.45x.

I believe this is caused by the inclusion of the full stack snapshot. However, I don't see an immediate solution here, with the existing revm-inspectors tracing code.

Wodann requested a review from Copilot February 19, 2026 17:54

Wodann self-assigned this Feb 19, 2026

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feat: add backwards compatibility for Response::traces

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Wodann force-pushed the feat/tracing-back-compat branch from 87edb00 to 041399f Compare February 19, 2026 18:01

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misc: add changeset

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Wodann requested a review from a team February 20, 2026 19:49

Wodann marked this pull request as ready for review February 20, 2026 22:32

popescuoctavian reviewed Feb 23, 2026

View reviewed changes

popescuoctavian and others added 2 commits February 23, 2026 14:54

address feedback

df5f2c5

Merge branch 'main' into feat/tracing-back-compat

369dc66

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Wodann mentioned this pull request Mar 3, 2026

build: upgrade to Rust v1.91.0 #1318

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	if matches!(step.op, OpCode::CREATE \| OpCode::CREATE2) \|\| !should_skip_call(trace) {
	if matches!(step.op, OpCode::CREATE \| OpCode::CREATE2) \|\| !should_skip_call(&node.trace) {

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Hardhat Plugin Compatibility Report — EDR Tracing Back-Compat

Overview

Critical Finding: includeCallTraces Default

Plugin Test Suite Results

hardhat-gas-reporter v2.3.0

solidity-coverage v0.8.17

hardhat-tracer v3.4.0

Third-Party Project Results (with linked plugins)

Seaport (best result — full validation)

OpenZeppelin Contracts v5.5.0

NexusMutual

Additional projects tested (stock plugins, local Hardhat+EDR)

Non-Trace Issues Found

Risk Assessment

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Wodann commented Feb 19, 2026 •

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Critical Finding: `includeCallTraces` Default

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