analyzerutil

Documentation

Overview

Package analyzerutil provides implementation helpers for analyzers.

Index

• func ExtractDoc(content, name string) (string, error)
• func FileUsesGoVersion(pass *analysis.Pass, file *ast.File, version string) (_res bool)
• func MustExtractDoc(content, name string) string
• func ReadFile(pass *analysis.Pass, filename string) ([]byte, *token.File, error)

Functions

func ExtractDoc

func ExtractDoc(content, name string) (string, error)

ExtractDoc extracts a section of a package doc comment from the provided contents of an analyzer package's doc.go file.

A section is a portion of the comment between one heading and the next, using this form:

# Analyzer NAME

NAME: SUMMARY

Full description...

where NAME matches the name argument, and SUMMARY is a brief verb-phrase that describes the analyzer. The following lines, up until the next heading or the end of the comment, contain the full description. ExtractDoc returns the portion following the colon, which is the form expected by Analyzer.Doc.

Example:

# Analyzer printf

printf: checks consistency of calls to printf

The printf analyzer checks consistency of calls to printf.
Here is the complete description...

This notation allows a single doc comment to provide documentation for multiple analyzers, each in its own section. The HTML anchors generated for each heading are predictable.

It returns an error if the content was not a valid Go source file containing a package doc comment with a heading of the required form.

This machinery enables the package documentation (typically accessible via the web at https://pkg.go.dev/) and the command documentation (typically printed to a terminal) to be derived from the same source and formatted appropriately.

func FileUsesGoVersion

func FileUsesGoVersion(pass *analysis.Pass, file *ast.File, version string) (_res bool)

FileUsesGoVersion reports whether the specified file may use features of the specified version of Go (e.g. "go1.24").

Tip: we recommend using this check "late", just before calling pass.Report, rather than "early" (when entering each ast.File, or each candidate node of interest, during the traversal), because the operation is not free, yet is not a highly selective filter: the fraction of files that pass most version checks is high and increases over time.

func MustExtractDoc

func MustExtractDoc(content, name string) string

MustExtractDoc is like ExtractDoc but it panics on error.

To use, define a doc.go file such as:

// Package halting defines an analyzer of program termination.
//
// # Analyzer halting
//
// halting: reports whether execution will halt.
//
// The halting analyzer reports a diagnostic for functions
// that run forever. To suppress the diagnostics, try inserting
// a 'break' statement into each loop.
package halting

import _ "embed"

//go:embed doc.go
var doc string

And declare your analyzer as:

var Analyzer = &analysis.Analyzer{
	Name:             "halting",
	Doc:              analyzerutil.MustExtractDoc(doc, "halting"),
	...
}

func ReadFile

func ReadFile(pass *analysis.Pass, filename string) ([]byte, *token.File, error)

ReadFile reads a file and adds it to the FileSet in pass so that we can report errors against it using lineStart.