PMM-15129 PMM-15129 Fix noinlineerr Go linter issues in agent

[maxkondr]

Ticket number: PMM-15129

Percona-Lab/pmm-submodules#4400

[Copilot]

Pull request overview

This PR addresses Go linter (noinlineerr) warnings across the PMM agent/admin code by refactoring inline error checks (e.g., if err := ...; err != nil) into separate assignment + conditional blocks, without changing intended behavior.

Changes:

• Replaced inline if err := ...; err != nil patterns with err = ... / if err != nil across agent, admin, and API packages.
• Adjusted a few spots where := previously scoped variables tightly (e.g., command responses, DB calls, file ops) to satisfy the linter’s requirements.
• Minor import and local variable handling updates to support the refactors.

Reviewed changes

Copilot reviewed 33 out of 33 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
api/agent/v1/metadata.go	Refactors metrics port parsing to avoid inline error initialization.
agent/utils/version/mongo.go	Splits MongoDB command error/decode checks into assignment + conditional.
agent/utils/tests/mongodb.go	Refactors decode error handling in test utility.
agent/utils/templates/template.go	Refactors temp dir cleanup/create error handling to satisfy linter.
agent/utils/filereader/continuous_file_reader.go	Refactors file seek/close error handling to avoid inline err declarations.
agent/serviceinfobroker/service_info_broker.go	Refactors DB ping/query/scan error checks across service info helpers.
agent/runner/runner.go	Refactors token acquisition error checks for jobs/actions.
agent/runner/jobs/mysql_restore_job.go	Refactors multiple restore-step error checks (systemctl, exec, filesystem).
agent/runner/jobs/mysql_backup_job.go	Refactors command start error checks during backup pipeline setup.
agent/runner/jobs/mongodb_restore_job.go	Refactors PBM configuration/wait error checks.
agent/runner/jobs/mongodb_backup_job.go	Refactors PBM configuration/wait error checks.
agent/runner/actions/pt_mysql_summary_action.go	Refactors arg validation and template execution error checks.
agent/runner/actions/mysql_show_create_table_action.go	Refactors row scan error check.
agent/runner/actions/mysql_explain_action.go	Refactors write/flush/unmarshal error checks to avoid inline err declarations.
agent/runner/actions/mongodb_query_admincommand_action.go	Refactors BSON decode error check.
agent/connectionchecker/connection_checker.go	Refactors ping checks for MySQL/MongoDB/PostgreSQL/ProxySQL.
agent/config/config.go	Refactors host/port parsing and config loading/unmarshal error checks.
agent/commands/setup.go	Refactors error checks and updates typed error extraction patterns for linter compliance.
agent/cmd/pmm-agent-entrypoint/main.go	Refactors signal/process waiting and prerun command error checks.
agent/client/client.go	Refactors timeout validity check to avoid inline err declaration.
agent/agents/supervisor/supervisor.go	Refactors port release and temp dir cleanup error handling.
agent/agents/postgres/pgstatstatements/pgstatstatements.go	Refactors cache get/set error handling around stat statement refresh.
agent/agents/postgres/pgstatmonitor/pgstatmonitor.go	Refactors initial cache seeding error handling.
agent/agents/postgres/parser/parser.go	Refactors parse-to-JSON error handling.
agent/agents/mysql/slowlog/slowlog.go	Refactors multiple query/scan/fs operations error handling in slowlog checks/rotation.
agent/agents/mysql/perfschema/perfschema.go	Refactors cache get/set and initial summary fetch error handling.
agent/agents/mongodb/mongolog/internal/monitor_test.go	Refactors scanner/write error checks in tests.
agent/agentlocal/agent_local.go	Refactors JSON gateway registration and HTTP server shutdown error checks.
agent/agentlocal/agent_local_test.go	Refactors zip entry read error check in test.
admin/commands/summary.go	Refactors URL parse and archive file create error checks.
admin/commands/status.go	Refactors URL parse error check when redacting server URL.
admin/commands/base.go	Refactors JSON unmarshal error check for credentials parsing.
admin/cmd/pmm-admin/main_test.go	Refactors JSON unmarshal error check in version output test.

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[codecov]

Codecov Report

❌ Patch coverage is 36.57143% with 111 lines in your changes missing coverage. Please review.
✅ Project coverage is 43.51%. Comparing base (0fcef19) to head (6887260).

Files with missing lines	Patch %	Lines
agent/runner/jobs/mysql_restore_job.go	0.00%	32 Missing ⚠️
agent/commands/setup.go	0.00%	9 Missing ⚠️
agent/agents/mysql/slowlog/slowlog.go	53.33%	1 Missing and 6 partials ⚠️
agent/cmd/pmm-agent-entrypoint/main.go	0.00%	7 Missing ⚠️
agent/agents/mysql/perfschema/perfschema.go	40.00%	2 Missing and 4 partials ⚠️
agent/runner/jobs/mongodb_backup_job.go	0.00%	6 Missing ⚠️
agent/runner/jobs/mongodb_restore_job.go	0.00%	6 Missing ⚠️
agent/agentlocal/agent_local.go	0.00%	4 Missing ⚠️
...ents/postgres/pgstatstatements/pgstatstatements.go	33.33%	2 Missing and 2 partials ⚠️
agent/runner/jobs/mysql_backup_job.go	0.00%	4 Missing ⚠️
... and 14 more

Additional details and impacted files

@@                           Coverage Diff                            @@
##           PMM-15129-noinlineerr-linter-managed    #5483      +/-   ##
========================================================================
- Coverage                                 43.52%   43.51%   -0.01%     
========================================================================
  Files                                       413      413              
  Lines                                     42849    42928      +79     
========================================================================
+ Hits                                      18648    18682      +34     
- Misses                                    22329    22374      +45     
  Partials                                   1872     1872              

Flag	Coverage Δ
admin	34.78% <50.00%> (+0.03%)	⬆️
agent	49.04% <35.92%> (-0.09%)	⬇️
managed	42.86% <ø> (+0.01%)	⬆️
vmproxy	72.22% <ø> (ø)

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