Reduce allocation in AutoFormat by ReneWerner87 · Pull Request #3652 · gofiber/fiber

ReneWerner87 · 2025-08-01T15:11:29Z

Summary

store a *DefaultCtx pointer in DefaultReq and DefaultRes
calling methods directly on the concrete ctx avoids extra interface overhead

Testing

make test
go test -run=^$ -bench=Benchmark_Ctx_AutoFormat_JSON -benchmem ./...

https://chatgpt.com/codex/tasks/task_e_688884e30b488326864546b7b4609d74

coderabbitai · 2025-08-01T15:11:36Z

Walkthrough

The type of the c field in both DefaultReq and DefaultRes structs was changed from the interface type Ctx to a pointer to the concrete type DefaultCtx. No other logic or code changes were made.

Changes

Cohort / File(s)	Change Summary
DefaultReq struct context field `req.go`	Changed the type of the `c` field in `DefaultReq` from `Ctx` to `*DefaultCtx`.
DefaultRes struct context field `res.go`	Changed the type of the `c` field in `DefaultRes` from `Ctx` to `*DefaultCtx`.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

Possibly related issues

🧹 [Maintenance]: Refactor DefaultReq and DefaultRes fields #3632: This PR implements the exact field type change from Ctx to *DefaultCtx in DefaultReq and DefaultRes as described in the issue.

Possibly related PRs

v3: Consolidate Logic of Handling the Request Body #3093: Related through changes to how DefaultCtx is used, which is directly affected by this PR's type changes.
🔥 feat: Add support for embedded Koa-Style Req and Res structs #3533: Related due to both PRs restructuring the embedding and reference of context, request, and response structs.

Suggested labels

⚡️ Performance, v3

Suggested reviewers

gaby
efectn
sixcolors

Poem

The structs now point, not interface,
To DefaultCtx in a single place.
Less allocation, more direct,
Cleaner code we now perfect.
A hop, a skip, a pointer’s cheer—
The fiber rabbit’s changes here! 🐇

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📜 Recent review details

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Review profile: CHILL
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📥 Commits

Reviewing files that changed from the base of the PR and between a838dfb and a0e8c7c.

📒 Files selected for processing (2)

req.go (1 hunks)
res.go (1 hunks)

🧰 Additional context used

🧠 Learnings (4)

📓 Common learnings

Learnt from: gaby
PR: gofiber/fiber#3193
File: middleware/cache/cache_test.go:897-897
Timestamp: 2024-11-08T04:10:42.990Z
Learning: In the Fiber framework, `Context()` is being renamed to `RequestCtx()`, and `UserContext()` to `Context()` to improve clarity and align with Go's context conventions.

Learnt from: gaby
PR: gofiber/fiber#3193
File: middleware/adaptor/adaptor.go:111-111
Timestamp: 2024-11-10T23:44:13.704Z
Learning: In the `middleware/adaptor/adaptor.go` file of the Fiber framework, when updating context handling, replacing `c.Context()` with `c.RequestCtx()` is appropriate to access the `fasthttp.RequestCtx`.

Learnt from: sixcolors
PR: gofiber/fiber#3016
File: middleware/session/config.go:122-122
Timestamp: 2024-10-08T19:06:06.583Z
Learning: In `DefaultErrorHandler(c *fiber.Ctx, err error)`, since `c` is a pointer to an interface, we need to dereference `*c` when calling interface methods like `SendStatus`.

Learnt from: sixcolors
PR: gofiber/fiber#3016
File: middleware/session/config.go:122-122
Timestamp: 2024-09-25T16:18:34.719Z
Learning: In `DefaultErrorHandler(c *fiber.Ctx, err error)`, since `c` is a pointer to an interface, we need to dereference `*c` when calling interface methods like `SendStatus`.

Learnt from: sixcolors
PR: gofiber/fiber#3016
File: middleware/csrf/session_manager.go:30-43
Timestamp: 2024-09-25T16:15:39.392Z
Learning: In the session middleware, `session.FromContext(c)` returns `*session.Middleware`, whereas `m.session.Get(c)` returns `*session.Store`, so they are not directly interchangeable.

Learnt from: sixcolors
PR: gofiber/fiber#3016
File: middleware/csrf/session_manager.go:30-43
Timestamp: 2024-10-08T19:06:06.583Z
Learning: In the session middleware, `session.FromContext(c)` returns `*session.Middleware`, whereas `m.session.Get(c)` returns `*session.Store`, so they are not directly interchangeable.

Learnt from: ReneWerner87
PR: gofiber/fiber#3161
File: app.go:923-932
Timestamp: 2024-11-15T07:56:21.623Z
Learning: In the Fiber framework, breaking changes are acceptable when moving from version 2 to version 3, including modifications to method signatures such as in the `Test` method in `app.go`.

Learnt from: sixcolors
PR: gofiber/fiber#3016
File: middleware/csrf/csrf_test.go:188-193
Timestamp: 2024-10-08T19:06:06.583Z
Learning: In the Fiber framework tests, using `ctx.Response.Header.Cookie` may not be suitable for parsing cookies from the response header, as it requires a `*Cookie` and fills it rather than returning a string value; thus, manual parsing of the `Set-Cookie` header may be necessary.

Learnt from: sixcolors
PR: gofiber/fiber#3016
File: middleware/csrf/csrf_test.go:188-193
Timestamp: 2024-09-25T15:57:10.221Z
Learning: In the Fiber framework tests, using `ctx.Response.Header.Cookie` may not be suitable for parsing cookies from the response header, as it requires a `*Cookie` and fills it rather than returning a string value; thus, manual parsing of the `Set-Cookie` header may be necessary.

📚 Learning: in the `middleware/adaptor/adaptor.go` file of the fiber framework, when updating context handling, ...

Learnt from: gaby
PR: gofiber/fiber#3193
File: middleware/adaptor/adaptor.go:111-111
Timestamp: 2024-11-10T23:44:13.704Z
Learning: In the `middleware/adaptor/adaptor.go` file of the Fiber framework, when updating context handling, replacing `c.Context()` with `c.RequestCtx()` is appropriate to access the `fasthttp.RequestCtx`.

Applied to files:

req.go
res.go

📚 Learning: in the fiber framework, `context()` is being renamed to `requestctx()`, and `usercontext()` to `cont...

Learnt from: gaby
PR: gofiber/fiber#3193
File: middleware/cache/cache_test.go:897-897
Timestamp: 2024-11-08T04:10:42.990Z
Learning: In the Fiber framework, `Context()` is being renamed to `RequestCtx()`, and `UserContext()` to `Context()` to improve clarity and align with Go's context conventions.

Applied to files:

req.go
res.go

📚 Learning: in `defaulterrorhandler(c *fiber.ctx, err error)`, since `c` is a pointer to an interface, we need t...

Learnt from: sixcolors
PR: gofiber/fiber#3016
File: middleware/session/config.go:122-122
Timestamp: 2024-10-08T19:06:06.583Z
Learning: In `DefaultErrorHandler(c *fiber.Ctx, err error)`, since `c` is a pointer to an interface, we need to dereference `*c` when calling interface methods like `SendStatus`.

Applied to files:

req.go
res.go

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🔇 Additional comments (2)

res.go (1)

123-123: LGTM! Performance optimization by eliminating interface dispatch overhead.

Changing from the interface type Ctx to the concrete type *DefaultCtx eliminates the overhead of interface method calls, which aligns with the PR's objective of reducing allocations in AutoFormat. This is a clean optimization that maintains API compatibility while improving performance.

req.go (1)

31-31: LGTM! Consistent optimization across request and response structures.

This change mirrors the optimization in res.go, ensuring both DefaultReq and DefaultRes use the concrete *DefaultCtx type instead of the interface. This consistency provides uniform performance benefits across the request/response handling pipeline.

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Post copyable unit tests in a comment
Commit unit tests in branch codex/2025-08-01-15-11-23

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gemini-code-assist

Summary of Changes

Hello @ReneWerner87, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request implements a targeted performance optimization by modifying how context references are stored within the DefaultReq and DefaultRes structs. By switching from an interface type (Ctx) to a concrete pointer type (*DefaultCtx), the change aims to reduce memory allocations and eliminate the overhead associated with interface method calls, thereby improving the efficiency of context-related operations.

Highlights

Performance Optimization: The core change involves updating the DefaultReq and DefaultRes structs to hold a *DefaultCtx pointer instead of an Ctx interface. This is a direct optimization to reduce allocations and interface dispatch overhead.

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Copilot

Pull Request Overview

This PR optimizes memory allocation in the AutoFormat functionality by replacing interface references with concrete type pointers. The key optimization reduces interface overhead by allowing direct method calls on the concrete context type instead of going through interface dispatch.

Key changes:

Replace Ctx interface with *DefaultCtx concrete pointer in DefaultReq and DefaultRes structs
Enable direct method calls on concrete context to avoid interface allocation overhead

Reviewed Changes

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

File	Description
res.go	Changes `DefaultRes.c` field from `Ctx` interface to `*DefaultCtx` concrete pointer
req.go	Changes `DefaultReq.c` field from `Ctx` interface to `*DefaultCtx` concrete pointer

Copilot · 2025-08-01T15:12:02Z

res.go

 //go:generate ifacemaker --file res.go --struct DefaultRes --iface Res --pkg fiber --output res_interface_gen.go --not-exported true --iface-comment "Res is an interface for response-related Ctx methods."
 type DefaultRes struct {
-	c Ctx
+	c *DefaultCtx


Changing from interface Ctx to concrete type *DefaultCtx creates tight coupling and reduces flexibility. This breaks the dependency inversion principle and makes the code harder to test and extend. Consider if the performance gain justifies losing the ability to use different Ctx implementations.

Suggested change

c *DefaultCtx

c Ctx

Copilot · 2025-08-01T15:12:03Z

req.go

 //go:generate ifacemaker --file req.go --struct DefaultReq --iface Req --pkg fiber --output req_interface_gen.go --not-exported true --iface-comment "Req is an interface for request-related Ctx methods."
 type DefaultReq struct {
-	c Ctx
+	c *DefaultCtx


Changing from interface Ctx to concrete type *DefaultCtx creates tight coupling and reduces flexibility. This breaks the dependency inversion principle and makes the code harder to test and extend. Consider if the performance gain justifies losing the ability to use different Ctx implementations.

Suggested change

c *DefaultCtx

c Ctx

codecov · 2025-08-01T15:13:05Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.79%. Comparing base (a838dfb) to head (154c087).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3652      +/-   ##
==========================================
- Coverage   91.82%   91.79%   -0.03%     
==========================================
  Files         113      113              
  Lines       11421    11421              
==========================================
- Hits        10487    10484       -3     
- Misses        671      673       +2     
- Partials      263      264       +1

Flag	Coverage Δ
unittests	`91.79% <ø> (-0.03%)`	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

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gemini-code-assist

Code Review

This pull request reduces allocation in AutoFormat by storing a *DefaultCtx pointer in DefaultReq and DefaultRes, and calling methods directly on the concrete ctx to avoid extra interface overhead. The changes are clean and correct.

github-actions

⚠️ Performance Alert ⚠️

Possible performance regression was detected for benchmark.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 1.50.

Benchmark suite	Current: `154c087`	Previous: `a838dfb`	Ratio
`BenchmarkAppendMsgitem-4_middleware_csrf`	`0.6226` ns/op 1606.16 MB/s 0 B/op 0 allocs/op	`0.312` ns/op 3204.99 MB/s 0 B/op 0 allocs/op	`2.00`
`BenchmarkAppendMsgitem-4_middleware_csrf - ns/op`	`0.6226` ns/op	`0.312` ns/op	`2.00`
`BenchmarkAppendMsgstorageManager - MB/s`	`3210.65` MB/s	`1590.45` MB/s	`2.02`

This comment was automatically generated by workflow using github-action-benchmark.

store ctx pointers in req and res

a0e8c7c

Copilot AI review requested due to automatic review settings August 1, 2025 15:11

ReneWerner87 requested a review from a team as a code owner August 1, 2025 15:11

ReneWerner87 requested review from efectn, gaby and sixcolors August 1, 2025 15:11

ReneWerner87 added the codex label Aug 1, 2025 — with ChatGPT Codex Connector

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ReneWerner87 mentioned this pull request Aug 1, 2025

🧹 [Maintenance]: Refactor DefaultReq and DefaultRes fields #3632

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Merge branch 'main' into codex/2025-08-01-15-11-23

154c087

ReneWerner87 added ⚡️ Performance v3 labels Aug 1, 2025

ReneWerner87 added this to v3 Aug 1, 2025

ReneWerner87 added this to the v3 milestone Aug 1, 2025

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ReneWerner87 merged commit b446888 into main Aug 1, 2025
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ReneWerner87 deleted the codex/2025-08-01-15-11-23 branch August 1, 2025 15:41

github-project-automation bot moved this to Done in v3 Aug 1, 2025

coderabbitai bot mentioned this pull request Aug 11, 2025

🧹 chore: Respect immutable config in Params(), Protocol(), and Body() #3676

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coderabbitai bot mentioned this pull request Aug 20, 2025

♻️ Refactor: Improve Req/Res Benchmarks #3693

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Reduce allocation in AutoFormat#3652

Reduce allocation in AutoFormat#3652
ReneWerner87 merged 2 commits intomainfrom
codex/2025-08-01-15-11-23

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