Support regular expression (#3)

* Add test

* Support regexp path

* Add README about regexp support

* Copy test directry to run paralley

* Fix regular expression

* Rename to d

* Fix bug

* Use pointer receiver for consistency

* Use errors.New

README.md

@@ -18,3 +18,18 @@ importas \
   -alias knative.dev/serving/pkg/apis/serving/v1:servingv1 \
   ./...
 ~~~~
+
+### Use regular expression
+
+You can specify the package path by regular expression, and alias by regular expression replacement syntax like following snippet.
+
+~~~~
+importas -alias 'knative.dev/serving/pkg/apis/(\w+)/(v[\w\d]+):$1$2'
+~~~~
+
+`$1` represents the text of the first submatch. See [detail](https://golang.org/pkg/regexp/#Regexp.Expand).
+
+So it will enforce that
+
+"knative.dev/serving/pkg/apis/autoscaling/v1alpha1" is aliased by "autoscalingv1alpha1", and
+"knative.dev/serving/pkg/apis/serving/v1" is aliased by "servingv1"

analyzer.go

@@ -12,10 +12,6 @@ import (
 	"golang.org/x/tools/go/ast/inspector"
 )
 
-type Config struct {
-	RequiredAlias map[string]string // path -> alias.
-}
-
 var Analyzer = &analysis.Analyzer{
 	Name: "importas",
 	Doc:  "Enforces consistent import aliases",
@@ -26,15 +22,19 @@ var Analyzer = &analysis.Analyzer{
 	Requires: []*analysis.Analyzer{inspect.Analyzer},
 }
 
-var config = Config{
+var config = &Config{
 	RequiredAlias: make(map[string]string),
 }
 
 func run(pass *analysis.Pass) (interface{}, error) {
 	return runWithConfig(config, pass)
 }
 
-func runWithConfig(config Config, pass *analysis.Pass) (interface{}, error) {
+func runWithConfig(config *Config, pass *analysis.Pass) (interface{}, error) {
+	if err := config.CompileRegexp(); err != nil {
+		return nil, err
+	}
+
 	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
 	inspect.Preorder([]ast.Node{(*ast.ImportSpec)(nil)}, func(n ast.Node) {
 		visitImportSpecNode(n.(*ast.ImportSpec), pass)
@@ -62,7 +62,7 @@ func visitImportSpecNode(node *ast.ImportSpec, pass *analysis.Pass) {
 		pass.Reportf(node.Pos(), "import not quoted")
 	}
 
-	if required, exists := config.RequiredAlias[path]; exists && required != alias {
+	if required, exists := config.AliasFor(path); exists && required != alias {
 		pass.Report(analysis.Diagnostic{
 			Pos:     node.Pos(),
 			End:     node.End(),

analyzer_test.go

@@ -42,6 +42,13 @@ func TestAnalyzer(t *testing.T) {
 				"knative.dev/serving/pkg/apis/serving/v1":           "servingv1",
 			},
 		},
+		{
+			desc: "regexp",
+			pkg:  "d",
+			aliases: stringMap{
+				"knative.dev/serving/pkg/apis/(\\w+)/(v[\\w\\d]+)": "$1$2",
+			},
+		},
 	}
 
 	for _, test := range testCases {

config.go

@@ -0,0 +1,68 @@
+package importas
+
+import (
+	"errors"
+	"fmt"
+	"regexp"
+)
+
+type Config struct {
+	RequiredAlias map[string]string
+	Rules         []*Rule
+}
+
+func (c *Config) CompileRegexp() error {
+	rules := make([]*Rule, 0, len(c.RequiredAlias))
+	for path, alias := range c.RequiredAlias {
+		reg, err := regexp.Compile(fmt.Sprintf("^%s$", path))
+		if err != nil {
+			return err
+		}
+
+		rules = append(rules, &Rule{
+			Regexp: reg,
+			Alias:  alias,
+		})
+	}
+
+	c.Rules = rules
+	return nil
+}
+
+func (c *Config) findRule(path string) *Rule {
+	for _, rule := range c.Rules {
+		if rule.Regexp.MatchString(path) {
+			return rule
+		}
+	}
+
+	return nil
+}
+
+func (c *Config) AliasFor(path string) (string, bool) {
+	rule := c.findRule(path)
+	if rule == nil {
+		return "", false
+	}
+
+	alias, err := rule.aliasFor(path)
+	if err != nil {
+		return "", false
+	}
+
+	return alias, true
+}
+
+type Rule struct {
+	Alias  string
+	Regexp *regexp.Regexp
+}
+
+func (r *Rule) aliasFor(path string) (string, error) {
+	str := r.Regexp.FindString(path)
+	if len(str) > 0 {
+		return r.Regexp.ReplaceAllString(str, r.Alias), nil
+	}
+
+	return "", errors.New("mismatch rule")
+}

testdata/src/d/d.go

@@ -0,0 +1,11 @@
+package c
+
+import (
+	v1alpha1 "knative.dev/serving/pkg/apis/autoscaling/v1alpha1" // want `import "knative.dev/serving/pkg/apis/autoscaling/v1alpha1" imported as "v1alpha1" but must be "autoscalingv1alpha1" according to config`
+	v1 "knative.dev/serving/pkg/apis/serving/v1"                 // want `import "knative.dev/serving/pkg/apis/serving/v1" imported as "v1" but must be "servingv1" according to config`
+)
+
+func foo() {
+	v1alpha1.Resource("")
+	v1.Resource("")
+}

testdata/src/d/d.go.golden

@@ -0,0 +1,11 @@
+package c
+
+import (
+	autoscalingv1alpha1 "knative.dev/serving/pkg/apis/autoscaling/v1alpha1" // want `import "knative.dev/serving/pkg/apis/autoscaling/v1alpha1" imported as "v1alpha1" but must be "autoscalingv1alpha1" according to config`
+	servingv1 "knative.dev/serving/pkg/apis/serving/v1"                     // want `import "knative.dev/serving/pkg/apis/serving/v1" imported as "v1" but must be "servingv1" according to config`
+)
+
+func foo() {
+	autoscalingv1alpha1.Resource("")
+	servingv1.Resource("")
+}

testdata/src/d/go.mod

@@ -0,0 +1,5 @@
+module github.com/julz/importas/testdata/src/c
+
+go 1.15
+
+require knative.dev/serving v0.21.0