Upgrade Go to 1.26.3

[thomasmaas]

Upgrade Go from 1.25.9 to 1.26.3.

Changes:

• go.mod: updated go directive from 1.25.9 to 1.26.3
• Dockerfile: updated builder image from golang:1.25 to golang:1.26

Summary by CodeRabbit

• Chores

  • Updated the Go toolchain to 1.26.3.
  • Upgraded the local golangci-lint tool version to v2.12.2.

• Refactor

  • Improved CEL string assembly internals without changing the resulting output.

• Tests

  • Streamlined test environment setup for CEL extensions with equivalent behaviour.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: dea5bcec-086f-4cfe-98fb-c51cc0563f52

📥 Commits

Reviewing files that changed from the base of the PR and between 9ce8b64 and 5a64015.

📒 Files selected for processing (11)

• api/v1/common_types.go
• api/v1beta1/topology.go
• cmd/extensions/oidc-policy/internal/controller/oidcpolicy_reconciler.go
• cmd/extensions/plan-policy/api/v1alpha1/planpolicy_types.go
• internal/controller/consoleplugin_reconciler.go
• internal/controller/ratelimit_workflow_helpers.go
• internal/controller/route_policy_discoverability_reconciler.go
• internal/controller/state_of_the_world.go
• internal/policymachinery/utils.go
• pkg/cel/ext/kuadrant_test.go
• pkg/extension/controller/builder.go

📝 Walkthrough

Walkthrough

Go toolchain is upgraded from 1.25/1.25.9 to 1.26/1.26.3 across Dockerfile and go.mod. Golangci-lint is bumped from v2.7.2 to v2.12.2 with installation switched to version-pinned release URLs. Two utility functions are refactored: CEL tier list building now uses fmt.Fprintf directly, and test environment setup preallocates slice capacity.

Changes

Go 1.26 and Build Toolchain Updates

Layer / File(s)	Summary
Go 1.26 version update Dockerfile, go.mod	Builder stage base image updated from golang:1.25 to golang:1.26; go directive updated from 1.25.9 to 1.26.3.
Golangci-lint version and installation upgrade Makefile	GOLANGCI_LINT_VERSION bumped from v2.7.2 to v2.12.2; installation recipe changed to fetch install.sh from version-pinned release path instead of master branch.
CEL tier list string building refactoring cmd/extensions/plan-policy/api/v1alpha1/planpolicy_types.go	PlanPolicy.BuildCelExpression refactored to write tier list and predicate strings using fmt.Fprintf into strings.Builder instead of fmt.Sprintf with WriteString calls.
Test environment slice allocation refactoring pkg/cel/ext/kuadrant_test.go	testKuadrantEnv refactored to preallocate baseOpts slice with computed capacity instead of using literal single-element slice.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

Possibly related issues

• Upgrade Go to 1.25.9 across all repos #1886: Tracks Go toolchain upgrade (previously to 1.25.9); this PR advances to Go 1.26.3 using the same pattern.

Possibly related PRs

• Kuadrant/kuadrant-operator#1945: Previously bumped Go toolchain to 1.25.9 in go.mod and Dockerfile; this PR moves both files forward to 1.26.3.

Suggested reviewers

• eguzki

Poem

🐇 Four changes hippety-bound,
New versions and refactors abound!
From Go 1.25 to 1.26 we spring,
With linters and builders—a toolchain thing.
The rabbit hops onward, optimised and bright! ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The pull request title directly and accurately summarizes the main change: upgrading Go from version 1.25.9 to 1.26.3 across multiple configuration files.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch upgrade-go-1.26.3

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[coderabbitai]

🧹 Nitpick comments (1)

Dockerfile (1)

6-6: 🧹 Nitpick | 🔵 Trivial | ⚡ Quick win

Pin the builder image to golang:1.26.3 to match the module toolchain declaration.

Using golang:1.26 keeps builds on a floating patch line, which can make image builds non-reproducible versus go.mod (go 1.26.3). Prefer pinning the Docker base image to the same patch level.

Suggested diff

-FROM --platform=$BUILDPLATFORM golang:1.26 AS builder
+FROM --platform=$BUILDPLATFORM golang:1.26.3 AS builder

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@Dockerfile` at line 6, Update the golang base image version in the FROM
statement from golang:1.26 to golang:1.26.3 to match the go.mod toolchain
declaration and ensure reproducible builds by pinning to the exact patch version
rather than a floating patch line.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@Dockerfile`:
- Line 6: Update the golang base image version in the FROM statement from
golang:1.26 to golang:1.26.3 to match the go.mod toolchain declaration and
ensure reproducible builds by pinning to the exact patch version rather than a
floating patch line.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: a70e304f-b5ad-4a38-b1ea-34a0a874ab4f

📥 Commits

Reviewing files that changed from the base of the PR and between b199cd1 and 7145d99.

📒 Files selected for processing (2)

• Dockerfile
• go.mod

[codecov]

Codecov Report

❌ Patch coverage is 79.16667% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 45.71%. Comparing base (c821eb0) to head (3012a35).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...troller/route_policy_discoverability_reconciler.go	0.00%	2 Missing ⚠️
api/v1/common_types.go	0.00%	1 Missing ⚠️
api/v1beta1/topology.go	0.00%	1 Missing ⚠️
pkg/extension/controller/builder.go	0.00%	1 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (c821eb0) and HEAD (3012a35). Click for more details.

HEAD has 6 uploads less than BASE

Flag	BASE (c821eb0)	HEAD (3012a35)
envoygateway-integration	1	0
controllers-integration	3	0
istio-integration	2	0

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #2050       +/-   ##
===========================================
- Coverage   75.14%   45.71%   -29.44%     
===========================================
  Files         127      127               
  Lines       12626    12628        +2     
===========================================
- Hits         9488     5773     -3715     
- Misses       2659     6531     +3872     
+ Partials      479      324      -155     

Flag	Coverage Δ
bare-k8s-integration	20.13% <39.13%> (-0.01%)	⬇️
controllers-integration	?
envoygateway-integration	?
gatewayapi-integration	16.05% <39.13%> (-0.09%)	⬇️
istio-integration	?
unit	28.69% <41.66%> (+<0.01%)	⬆️

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

Components	Coverage Δ
api (u)	35.34% <0.00%> (-50.54%)	⬇️
internal (u)	46.79% <90.47%> (-29.80%)	⬇️
pkg (u)	39.13% <0.00%> (ø)

Files with missing lines	Coverage Δ
internal/controller/consoleplugin_reconciler.go	80.51% <100.00%> (ø)
internal/controller/ratelimit_workflow_helpers.go	55.55% <100.00%> (-24.93%)	⬇️
internal/controller/state_of_the_world.go	72.61% <100.00%> (-10.85%)	⬇️
internal/policymachinery/utils.go	90.42% <100.00%> (-4.79%)	⬇️
api/v1/common_types.go	0.00% <0.00%> (-100.00%)	⬇️
api/v1beta1/topology.go	85.71% <0.00%> (-7.94%)	⬇️
pkg/extension/controller/builder.go	38.82% <0.00%> (ø)
...troller/route_policy_discoverability_reconciler.go	17.96% <0.00%> (-77.31%)	⬇️

... and 65 files with indirect coverage changes

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• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[thomasmaas]

Needs a rebase once #2052 has been merged

[eguzki]

#2052 has been merged. Rebase to go