Fix more errorlint warnings. Use errors.As and errors.Is for error handling.

[atombrella]

What this PR does / why we need it:

Use errors.As instead of type-casting, errors.Is for comparison and use of %w for error formatting in fmt.Errorf. The changes do not fully fix all of errorlint. I don't feel comfortable touching files under v1-3 as this may break compatibility with API users.

I have not successfully been able to change the use of switch with comparison of the error type. There are a few instances of this:

pkg/provenance/sign_test.go:401:9: type switch on error will fail on wrapped errors. Use errors.As to check for specific errors (errorlint)
	switch err.(type) {
	       ^
pkg/strvals/parser.go:247:4: switch on an error will fail on wrapped errors. Use errors.Is to check for specific errors (errorlint)
			case io.EOF:
			^
pkg/strvals/parser.go:379:3: switch on an error will fail on wrapped errors. Use errors.Is to check for specific errors (errorlint)
		case io.EOF:

Special notes for your reviewer:

If applicable:

• this PR contains user facing changes (the docs needed label should be applied if so)
• this PR contains unit tests
• this PR has been tested for backwards compatibility

[gjenkins8]

Changes look good. Thanks!

These large refactor PRs, while valid, can be difficult to merge due to coordinating two maintainers before a conflict arises.

Can you please fix the conflicts, and I can re-approve. And hopefully another maintainer before a conflict arises.

[atombrella]

Changes look good. Thanks!

These large refactor PRs, while valid, can be difficult to merge due to coordinating two maintainers before a conflict arises.

Can you please fix the conflicts, and I can re-approve. And hopefully another maintainer before a conflict arises.

@gjenkins8 @TerryHowe Sure. I have fixed the merge-conflicts.

[Copilot]

Pull request overview

This pull request improves error handling across the Helm codebase by adopting modern Go error handling patterns. It replaces direct error comparisons with errors.Is, type assertions with errors.As, and uses %w instead of %v in fmt.Errorf to properly wrap errors.

Changes:

• Replaced direct error comparisons (err == specificError) with errors.Is(err, specificError) for better wrapped error support
• Replaced type assertions (err.(*Type)) with errors.As(err, &variable) for safer type checking
• Changed error formatting from %v to %w in fmt.Errorf calls to preserve error chains
• Grouped related constants in engine.go for better code organization

Reviewed changes

Copilot reviewed 30 out of 30 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
pkg/strvals/parser.go	Updated io.EOF comparisons to use errors.Is
pkg/strvals/literal_parser.go	Updated io.EOF comparisons to use errors.Is (contains critical bugs)
pkg/storage/driver/sql_test.go	Changed ErrReleaseNotFound comparison to errors.Is
pkg/storage/driver/sql.go	Updated error wrapping to use %w format
pkg/storage/driver/secrets_test.go	Changed ErrReleaseNotFound comparisons to errors.Is
pkg/storage/driver/cfgmaps_test.go	Changed ErrReleaseNotFound comparisons to errors.Is
pkg/registry/transport.go	Updated io.EOF comparison to use errors.Is
pkg/kube/wait.go	Replaced StatusError type assertion with errors.As
pkg/kube/client.go	Updated error comparisons and type assertions to use errors.Is and errors.As
pkg/engine/engine.go	Grouped constants and updated error wrapping to use %w
pkg/downloader/manager.go	Updated error wrapping to use %w format
pkg/downloader/chart_downloader_test.go	Changed ErrNoOwnerRepo comparison to errors.Is
pkg/downloader/chart_downloader.go	Changed ErrNoOwnerRepo comparison to errors.Is
pkg/cmd/upgrade.go	Changed ErrReleaseNotFound comparison to errors.Is
pkg/cmd/template.go	Updated error wrapping to use %w format
pkg/cmd/search_repo.go	Updated error wrapping to use %w format
pkg/cmd/search_hub.go	Updated error wrapping to use %w format
pkg/cmd/rollback.go	Updated error wrapping to use %w format
pkg/cmd/load_plugins.go	Replaced InvokeExecError type assertion with errors.As
pkg/cmd/lint.go	Updated error wrapping to use %w format
pkg/cmd/dependency_build.go	Replaced ErrRepoNotFound type assertion with errors.As
pkg/chart/loader/archive/archive.go	Updated io.EOF comparison and error wrapping
pkg/action/validate.go	Updated error wrapping to use %w format
pkg/action/upgrade.go	Updated error wrapping to use %w format
pkg/action/package_test.go	Changed error comparison to errors.Is
pkg/action/install.go	Updated error wrapping to use %w format
internal/sympath/walk.go	Changed filepath.SkipDir comparisons to errors.Is
internal/plugin/runtime_subprocess_test.go	Replaced InvokeExecError type assertion with errors.As
internal/plugin/runtime_subprocess.go	Replaced exec.ExitError type assertions with errors.As
internal/plugin/installer/local_installer_test.go	Changed ErrPluginNotADirectory comparison to errors.Is

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