Add Feature

Add a new Bicep language feature to bicep-docs

The canonical implementation pipeline:

1. Write a minimal Bicep fixture that exercises the new feature
2. Compile it with az bicep build to produce real ARM JSON
3. Inspect the ARM JSON to understand the exact schema
4. Update internal/types/types.go — add fields to the right struct(s)
5. Update internal/types/unmarshal.go — add JSON unmarshaling for new fields
6. Update internal/markdown/markdown.go — add rendering (new column, row, or section)
7. Update internal/markdown/create.go if a new section toggle is needed
8. Add test cases to the relevant *_test.go files
9. Verify: go test ./... then task lint

Step 1 — Write the Bicep fixture

Create test/<feature-name>.bicep with the minimum Bicep that exercises the new feature. Keep it alongside the existing test/any.bicep pattern — one focused fixture per capability.

// test/secure-params.bicep  (example for @secure() feature)
@secure()
param adminPassword string

@secure()
param config object

Also add a companion fixture in internal/template/testdata/<feature-name>.bicep if the feature needs to be covered by the template package unit tests (check whether existing fixtures like extended.bicep can be extended instead of creating a new one).

Step 2 — Compile to ARM JSON

az bicep build --file test/<feature-name>.bicep --outfile test/<feature-name>.json

If az is not available, try bicep build test/<feature-name>.bicep --outfile test/<feature-name>.json.

Read the generated JSON immediately — it is the ground truth for what bicep-docs must parse.

Step 3 — Inspect the ARM JSON

Focus on the sections that bicep-docs parses:

Identify: which new JSON key(s) appear? What is their type (bool, string, object, array)? Are they present on existing objects or do they introduce a new top-level section?

Step 4 — Update internal/types/types.go

Add fields to the relevant struct(s). Follow existing patterns:

• Use json:"keyName" struct tags matching the ARM JSON key exactly.
• Use omitempty for optional fields.
• Use pointer types (*bool, *string) when the zero value (false, "") would be indistinguishable from "field absent" — especially important for bool flags.
• For nested objects, add a new named struct rather than an anonymous one.

// Example: adding Secure to Parameter and Output
type Parameter struct {
    // ... existing fields ...
    Secure bool `json:"-"` // derived from type string; not a direct JSON field
}

If the feature introduces a new top-level ARM JSON section (rare), add it to Template struct and add a corresponding Section constant and ParseSectionFromString case.

Step 5 — Update internal/types/unmarshal.go

Add or extend the UnmarshalJSON method for the affected type. The existing pattern uses a type alias to avoid infinite recursion:

func (p *Parameter) UnmarshalJSON(data []byte) error {
    type Alias Parameter
    aux := &struct{ *Alias }{Alias: (*Alias)(p)}
    if err := json.Unmarshal(data, &aux); err != nil {
        return err
    }

    // Handle type/ref first (existing)
    tr, err := unmarshalTypeOrRef(data)
    if err != nil {
        return err
    }
    p.Type = tr

    // NEW: derive Secure from the resolved type string
    p.Secure = p.Type == "secureString" || p.Type == "secureObject"

    return nil
}

For fields that appear as nested JSON objects (e.g., discriminator), unmarshal a minimal helper struct:

var raw struct {
    Discriminator *struct {
        PropertyName string            `json:"propertyName"`
        Mapping      map[string]any    `json:"mapping"`
    } `json:"discriminator"`
}
if err := json.Unmarshal(data, &raw); err != nil {
    return err
}
if raw.Discriminator != nil {
    u.Discriminator = &Discriminator{
        PropertyName: raw.Discriminator.PropertyName,
        Mapping:      raw.Discriminator.Mapping,
    }
}

Step 6 — Update internal/markdown/markdown.go

Find the function that generates the affected section (e.g., generateParametersSection, generateUserDefinedDataTypesSection). Follow the MarkdownTable pattern:

// To add a "Secure" column to Parameters:
// 1. Add "Secure" to the headers slice
// 2. Add the value to each row slice in the same position

headers := []string{"Name", "Status", "Type", "Secure", "Description", "Default"}
// ...
row := []string{
    p.Name,
    p.GetStatus().String(),
    extractType(p.Type),
    boolToYesNo(p.Secure),  // new field
    p.Description,
    formatDefault(p.DefaultValue),
}

The --show-all-decorators flag pattern (see showAllDecorators parameter in generateParametersSection) controls whether sparse columns are shown. Consider whether the new column should be gated behind that flag or always shown.

For a completely new section, follow the pattern of generateUserDefinedDataTypesSection: create a generate<Feature>Section function, add it to create.go's GenerateDocumentation dispatch, and add a Section constant.

Step 7 — Add test cases

Unit test for the new field (internal/types/*_test.go)

Add a table-driven test case to the existing test that covers the struct being changed. Use a real ARM JSON snippet (copy from the compiled fixture) as the input:

{
    name: "secure_string_param",
    input: []byte(`{"type":"secureString","metadata":{"description":"admin password"}}`),
    expectedResult: types.Parameter{
        Type:        "secureString",
        Secure:      true,
        Description: "admin password",
    },
    expectedError: nil,
},

Markdown rendering test (internal/markdown/*_test.go)

Add a case to the relevant table-driven test in create_test.go or markdown_test.go that exercises the new column/section with a minimal types.Template.

Template/parse test (internal/template/*_test.go)

If the feature affects parsing of the .bicep source (not just ARM JSON), add the fixture to the testdata directory and add a test case in parse_test.go or build_test.go.

Step 8 — Verify

go test ./...
task lint

Fix any lint issues before considering the feature done. Pay attention to:

• funlen violations if a table or switch grew too long — may need //nolint:funlen // reason
• mnd (magic numbers) for any new numeric constants — define them as named constants
• godot — all new exported comments must end with a period

Source: christosgalano/bicep-docs — distributed by TomeVault.