Implementing a custom lint tool¶

The go/analysis framework and this codebase are designed for flexibility. You may want to permanently disable certain default checks, ship a fixed check set rather than a long flag list, or add provider-specific checks of your own. All three are done by building your own binary.

cmd/tfsproutx/tfsproutx.go is the worked example — it does nothing but combine two analyzer lists:

package main

import (
    "github.com/jfrappier/tfsprout/helper/cmdflags"
    "github.com/jfrappier/tfsprout/passes"
    "github.com/jfrappier/tfsprout/xpasses"
    "golang.org/x/tools/go/analysis"
    "golang.org/x/tools/go/analysis/multichecker"
)

func main() {
    cmdflags.AddVersionFlag()

    var analyzers []*analysis.Analyzer
    analyzers = append(analyzers, passes.AllChecks...)
    analyzers = append(analyzers, xpasses.AllChecks...)
    multichecker.Main(analyzers...)
}

Your binary inherits the entire driver — flag parsing, help, -fix, -json, exit codes — from multichecker.Main.

Adding a few extra checks¶

The common case: all standard checks, plus the two extras you actually want.

package main

import (
    "github.com/jfrappier/tfsprout/helper/cmdflags"
    "github.com/jfrappier/tfsprout/passes"
    "github.com/jfrappier/tfsprout/xpasses/XR002"
    "github.com/jfrappier/tfsprout/xpasses/XR003"
    "golang.org/x/tools/go/analysis"
    "golang.org/x/tools/go/analysis/multichecker"
)

func main() {
    cmdflags.AddVersionFlag()

    analyzers := append([]*analysis.Analyzer{}, passes.AllChecks...)
    analyzers = append(analyzers, XR002.Analyzer, XR003.Analyzer)
    multichecker.Main(analyzers...)
}

Copy passes.AllChecks into a fresh slice rather than appending to it directly — append may write into the package-level slice's backing array.

Permanently excluding checks¶

There is no "all except" helper. To exclude a check, list the ones you want individually, the same way AllChecks is built in passes/checks.go:

analyzers := []*analysis.Analyzer{
    AT001.Analyzer,
    AT002.Analyzer,
    // AT003 deliberately omitted: conflicts with our naming convention
    S013.Analyzer,
}

Verbose, but explicit — and unlike a -AT003=false flag in CI, the decision and its reason live in code where they get reviewed.

Filtering by name is the compact alternative:

excluded := map[string]bool{"AT003": true, "R009": true}

var analyzers []*analysis.Analyzer
for _, a := range passes.AllChecks {
    if !excluded[a.Name] {
        analyzers = append(analyzers, a)
    }
}

This silently no-ops if a name is misspelled or a check is removed upstream, so consider asserting that every excluded name matched.

Adding your own checks¶

Provider-specific conventions — internal naming rules, a required attribute, a banned helper — are worth encoding as analyzers in your own repository. Import them alongside tfsprout's:

analyzers := append([]*analysis.Analyzer{}, passes.AllChecks...)
analyzers = append(analyzers, myprovider.NoDeprecatedClientAnalyzer)
multichecker.Main(analyzers...)

Two building blocks are exported for this, and using them means your checks behave like the built-in ones:

• helper/terraformtype/ — models Terraform Plugin SDK types: schema.Schema, schema.Resource, resource.TestCase, validation functions, diag types, along with field name constants and helpers such as DeclaresField.
• helper/astutils/ — generic Go AST utilities for basic literals, composite literals, function types, field lists, and package qualifiers.

The passes/ directory also exports the information-gathering analyzers your checks can depend on. For example, passes/helper/resource/retryfuncinfo returns information from all named and anonymous declarations of helper/resource.RetryFunc(), so a check about retry behavior needs no traversal of its own. See How tfsprout works.

Support //lintignore: in your own checks by requiring passes/commentignore and calling ignorer.ShouldIgnore(analyzerName, node) before reporting. See Adding an analyzer.

Versioning¶

Your tool depends on tfsprout as a normal Go module:

go get github.com/jfrappier/tfsprout@v0.1.1

Pin it. AllChecks gaining a member is a behavior change for everyone who runs your binary, and you want that to arrive with a version bump you chose.

Check IDs are stable and never reused, so referencing AT001.Analyzer will not silently become a different check across upgrades. See Checks and categories.