GODRIVER-3670 Run golangci-lint CLI migration

[prestonvasquez]

GODRIVER-3670

Summary

Upgrade golangci-lint usage and config to the current CLI, then applies linter-driven fixes across the repo. Clean up revive “unexported-return” issues and staticcheck warnings, grouped by package.

gosec issues are being tracked in #2245 due to complexity

Background & Motivation

golangci-lint is failing for unclear reasons.

[Copilot]

Pull request overview

This PR upgrades golangci-lint from v1.60.1 to v2.6.2 and updates the configuration to align with the v2 CLI format. The changes apply automated linter fixes across the codebase, including removing deprecated build tags, improving code clarity, and addressing revive and staticcheck warnings.

Key Changes:

• Migrated golangci-lint configuration from v1 to v2 format
• Removed legacy // +build tags (now redundant with //go:build)
• Applied automated code improvements suggested by linters (variable naming, boolean logic simplification, etc.)

Reviewed changes

Copilot reviewed 77 out of 77 changed files in this pull request and generated 12 comments.

Show a summary per file

File	Description
.golangci.yml	Migrated config to v2 format with updated linter settings and exclusion rules
etc/golangci-lint.sh	Updated golangci-lint version to 2.6.2
Multiple build tag files	Removed deprecated // +build tags across ~30 files
x/mongo/driver/topology/*.go	Fixed variable naming, simplified boolean expressions, removed blank lines
x/mongo/driver/session/client_session.go	Converted if-else chains to switch statements
x/mongo/driver/operation*.go	Simplified boolean logic with De Morgan's laws
x/bsonx/bsoncore/*.go	Changed objectID type to explicit [12]byte array
mongo/*.go	Renamed variables for clarity (Db→DB, MS→Time suffixes)
internal/integration/*.go	Updated test database naming and simplified loop conditions

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[mongodb-drivers-pr-bot]

API Change Report

No changes found!

[prestonvasquez]

Rejecting all AI suggestions that conflict with the golangci-lint static analysis --fix flag.

[mongodb-drivers-pr-bot]

🧪 Performance Results

Commit SHA: 423b421

The following benchmark tests for version 692dc8f60affd60007543cfc had statistically significant changes (i.e., |z-score| > 1.96):

Benchmark	Measurement	% Change	Patch Value	Stable Region	H-Score	Z-Score
BenchmarkBSONDeepDocumentDecoding	ops_per_second_min	-48.5941	1032.0951	Avg: 2007.7362 Med: 2008.1934 Stdev: 171.2408	0.9118	-5.6975
BenchmarkSmallDocInsertOne	total_time_seconds	-5.8379	1.1149	Avg: 1.1841 Med: 1.1847 Stdev: 0.0243	0.8147	-2.8458
BenchmarkBSONDeepDocumentDecoding	total_mem_allocs	-2.2651	12841321.0000	Avg: 13138933.9412 Med: 13173516.0000 Stdev: 135823.8667	0.7531	-2.1912
BenchmarkBSONDeepDocumentDecoding	total_bytes_allocated	-2.2583	279005152.0000	Avg: 285451439.5294 Med: 286201912.0000 Stdev: 2942934.7907	0.7530	-2.1904
BenchmarkBSONFullDocumentEncoding	allocated_bytes_per_op	0.0690	5201.0000	Avg: 5197.4118 Med: 5197.0000 Stdev: 1.3720	0.7917	2.6154

For a comprehensive view of all microbenchmark results for this PR's commit, please check out the Evergreen perf task for this patch.

[prestonvasquez]

RE: BenchmarkBSONDeepDocumentDecoding: we are still in the stability region.