What were the notable Go updates?

net/http/internal/http2: do not silently truncate large trailers, net/http: add Server.MaxHeaderValueCount setting, and math/big: fix edge case float formatting.

@golang

Go and the standard library - backend infrastructure at scale

github ↗

Pick a date

Topics: Go Infrastructure Full archive →

The Wire · Showcase

HTTP/2 TRAILER TRUNCATION BUG FIXED, HEADER LIMITS TIGHTENED ACROSS THE STACK

By RepoJournal · Filed 06:01 UTC on July 2, 2026 · About Go

Go's HTTP/2 implementation was silently dropping trailer headers that exceeded limits instead of erroring, a behavior now corrected alongside new per-server header count controls.

The most critical fix lands in net/http/internal/http2 [1], where trailers exceeding MaxResponseHeaderBytes would vanish without warning. That's the kind of silent data loss that surfaces months later in production. Paired with this, net/http gains a new MaxHeaderValueCount setting [2] that lets you limit header quantity while keeping MaxHeaderBytes high for legitimate large headers like SSO cookies, a real pain point for OIDC-heavy deployments. Meanwhile, math/big patches an edge case in float formatting [3] where trailing-zero trimming could push the index past the mantissa bounds, and golang/sync hardens semaphore.Weighted to panic on negative weights [4] instead of silently corrupting internal state. The tools ecosystem saw goimports skip js/wasm test execution [6] to fix CI noise, and gopls regained semantic token backwards compatibility [7] with v0.11.0 clients. One revert [5] pulled a header timeout check for HTTP/2 to keep rc2 consistent with the minors branch until rc3.

Action items

→ Review HTTP/2 trailer handling in production services using net/http golang/go [plan]
→ Evaluate MaxHeaderValueCount for services with large cookie headers golang/go [monitor]
→ Test semaphore.Weighted edge cases if you accept untrusted weight inputs golang/sync [plan]

References

[1] net/http/internal/http2: do not silently truncate large trailers golang/go
[2] net/http: add Server.MaxHeaderValueCount setting golang/go
[3] math/big: fix edge case float formatting golang/go
[4] semaphore: panic on negative weights golang/sync
[5] Revert "net/http: apply header timeout to server's unencrypted HTTP/2 check" golang/go
[6] cmd/goimports: skip TestCmd on js/wasm golang/tools
[7] gopls/internal/test: have semtok work with gopls@v0.11.0 golang/tools

Quick answers

What shipped in Go on July 2, 2026?: Go's HTTP/2 implementation was silently dropping trailer headers that exceeded limits instead of erroring, a behavior now corrected alongside new per-server header count controls. In total, 9 commits landed.
What were the notable Go updates?: net/http/internal/http2: do not silently truncate large trailers, net/http: add Server.MaxHeaderValueCount setting, and math/big: fix edge case float formatting.

COMPILER GETS SMARTER ABOUT FUNCTION ORDERING, BENCHMARK SUITE HITS BUILD SNAGS

Go's compiler now counts IR nodes to order functions more intelligently, while the benchmark harness stumbles on recent upgrades.

go 4 shipped 1-min read

@golang 2 days ago

GO STRIPS MIPS REGISTER ALLOCATOR SUPPORT

Go's compiler is ripping out HI/LO register support for MIPS, closing the door on a decade of architectural complexity that wasn't worth the maintenance tax.

go 2 shipped 1-min read

@golang 3 days ago

PRINTF ANALYZER GETS SMARTER, PLAYGROUND NEEDS GO 1.26

The printf linter stops falsely flagging intentional double newlines, while gotip now requires Go 1.26 to bootstrap.

go 13 shipped 1-min read

@golang 4 days ago

GO REWORKS HTTP/3 REGISTRATION, KILLS GLOBAL STATE IN MODULE LOADER

Damien Neil's paired changes to net/http and x/net/http3 fundamentally reshape how HTTP/3 integrates with the standard library, while Michael Matloob strips out state manipulation functions that no longer belong anywhere.

go 28 shipped 1-min read

Elsewhere on the wire

AI Agents about 21 hours ago

CLINE SHIPS FIVE CRITICAL AGENT FIXES AFTER END-TO-END TESTING BLITZ

Saoudrizwan just landed a cascade of fixes that prevent the agent loop from running wild, stop file reads from resolving to the wrong directory, and plug the compaction pipeline.

ai-agents 16 shipped 2-min read

Local LLMs about 21 hours ago

LLAMA.CPP SHIPS MINIMAX-M3 SPARSE ATTENTION, VLLM UNLOCKS HETEROGENEOUS PREFILL-DECODE

The inference stack gets a new model architecture and a fundamental shift in how prefill and decode can run on different hardware configurations.

+10

llms 125 shipped 1-min read

@CachyOS about 21 hours ago

GLIBC 2.43 REBUILD SHIPS, INSTALLER JUMPS TO C++26

CachyOS pushed glibc 2.43 through the pipeline while the CLI installer upgraded its C++ standard to C++26, signaling a major refresh across core infrastructure.

infra 97 shipped 1-min read

Elixir & Phoenix about 21 hours ago

ECTO FIXES SUBQUERY PLANNING IN JOINS, ELIXIR PATCHES IEX PARSING

Ecto's query planner now handles subqueries correctly in interpolated join filters, while Elixir fixes a syntax error that broke 'not in' as a continuation operator in IEx.