abigen: adding support for configurable template file for generating bindings

accounts/abi/abigen/bindv2.go

@@ -294,7 +294,7 @@ func iterSorted[V any](inp map[string]V, onItem func(string, V) error) error {
 // to be used as is in client code, but rather as an intermediate struct which
 // enforces compile time type safety and naming convention as opposed to having to
 // manually maintain hard coded strings that break on runtime.
-func BindV2(types []string, abis []string, bytecodes []string, pkg string, libs map[string]string, aliases map[string]string) (string, error) {
+func BindV2(types []string, abis []string, bytecodes []string, pkg string, libs map[string]string, aliases map[string]string, templateContent string) (string, error) {
 	b := binder{
 		contracts: make(map[string]*tmplContractV2),
 		structs:   make(map[string]*tmplStruct),
@@ -360,7 +360,7 @@ func BindV2(types []string, abis []string, bytecodes []string, pkg string, libs
 		"ispointertype":      isPointerType,
 		"underlyingbindtype": underlyingBindType,
 	}
-	tmpl := template.Must(template.New("").Funcs(funcs).Parse(tmplSourceV2))
+	tmpl := template.Must(template.New("").Funcs(funcs).Parse(templateContent))
 	if err := tmpl.Execute(buffer, data); err != nil {
 		return "", err
 	}

accounts/abi/abigen/bindv2_test.go

@@ -58,7 +58,7 @@ func bindCombinedJSON(test *bindV2Test) (string, error) {
 	if test.aliases == nil {
 		test.aliases = make(map[string]string)
 	}
-	code, err := BindV2(types, abis, bins, "bindtests", libs, test.aliases)
+	code, err := BindV2(types, abis, bins, "bindtests", libs, test.aliases, TmplSourceV2)
 	if err != nil {
 		return "", fmt.Errorf("error creating bindings: %v", err)
 	}

accounts/abi/abigen/template.go

@@ -133,4 +133,4 @@ var tmplSource string
 // for abigen v2 is based on.
 //
 //go:embed source2.go.tpl
-var tmplSourceV2 string
+var TmplSourceV2 string

accounts/abi/bind/v2/generate_test.go

@@ -40,6 +40,26 @@ import (
 // TestBindingGeneration tests that re-running generation of bindings does not result in
 // mutations to the binding code.
 func TestBindingGeneration(t *testing.T) {
+	BindGenerationWithExpectedOutput(t, abigen.TmplSourceV2, getCodeFromBindingsDotGo)
+}
+
+func TestBindingGenerationWithDifferentTemplate(t *testing.T) {
+	BindGenerationWithExpectedOutput(t, "package {{.Package}} //test template", getHarcodedCodeFromBindingsDotGo)
+}
+
+func getHarcodedCodeFromBindingsDotGo(t *testing.T, basePath string) string {
+	return "package " + strings.Replace(basePath, "internal/contracts/", "", -1) + " //test template\n"
+}
+
+func getCodeFromBindingsDotGo(t *testing.T, basePath string) string {
+	existingBindings, err := os.ReadFile(filepath.Join(basePath, "bindings.go"))
+	if err != nil {
+		t.Fatalf("ReadFile returned error: %v", err)
+	}
+	return string(existingBindings)
+}
+
+func BindGenerationWithExpectedOutput(t *testing.T, templateContent string, getExpectedCodeFunc func(t *testing.T, basePath string) string) {
 	matches, _ := filepath.Glob("internal/contracts/*")
 	var dirs []string
 	for _, match := range matches {
@@ -86,16 +106,13 @@ func TestBindingGeneration(t *testing.T) {
 			libPattern := crypto.Keccak256Hash([]byte(name)).String()[2:36] // the first 2 chars are 0x
 			libs[libPattern] = typeName
 		}
-		code, err := abigen.BindV2(types, abis, bins, dir, libs, make(map[string]string))
+		code, err := abigen.BindV2(types, abis, bins, dir, libs, make(map[string]string), templateContent)
 		if err != nil {
 			t.Fatalf("error creating bindings for package %s: %v", dir, err)
 		}
 
-		existingBindings, err := os.ReadFile(filepath.Join(basePath, "bindings.go"))
-		if err != nil {
-			t.Fatalf("ReadFile returned error: %v", err)
-		}
-		if code != string(existingBindings) {
+		expectedCode := getExpectedCodeFunc(t, basePath)
+		if code != expectedCode {
 			t.Fatalf("code mismatch for %s", dir)
 		}
 	}

cmd/abigen/main.go

@@ -67,6 +67,10 @@ var (
 		Name:  "alias",
 		Usage: "Comma separated aliases for function and event renaming.  If --v2 is set, errors are aliased as well. e.g. original1=alias1, original2=alias2",
 	}
+	templateFlag = &cli.StringFlag{
+		Name:  "template",
+		Usage: "Input file to use as template for generating bindings",
+	}
 	v2Flag = &cli.BoolFlag{
 		Name:  "v2",
 		Usage: "Generates v2 bindings",
@@ -86,6 +90,7 @@ func init() {
 		pkgFlag,
 		outFlag,
 		aliasFlag,
+		templateFlag,
 		v2Flag,
 	}
 	app.Action = generate
@@ -100,6 +105,9 @@ func generate(c *cli.Context) error {
 	if c.String(abiFlag.Name) == "" && c.String(jsonFlag.Name) == "" {
 		utils.Fatalf("Either contract ABI source (--abi) or combined-json (--combined-json) are required")
 	}
+	if !c.Bool(v2Flag.Name) && c.IsSet(templateFlag.Name) {
+		utils.Fatalf("Template configurabion only works with abigen v2")
+	}
 	// If the entire solidity code was specified, build and bind based on that
 	var (
 		abis    []string
@@ -216,7 +224,16 @@ func generate(c *cli.Context) error {
 		err  error
 	)
 	if c.IsSet(v2Flag.Name) {
-		code, err = abigen.BindV2(types, abis, bins, c.String(pkgFlag.Name), libs, aliases)
+		template := abigen.TmplSourceV2
+		if c.IsSet(templateFlag.Name) {
+			templateLoc := c.String(templateFlag.Name)
+			templateData, err := os.ReadFile(templateLoc)
+			if err != nil {
+				utils.Fatalf("Error reading template file: %s, error: %", templateLoc, err)
+			}
+			template = string(templateData)
+		}
+		code, err = abigen.BindV2(types, abis, bins, c.String(pkgFlag.Name), libs, aliases, template)
 	} else {
 		code, err = abigen.Bind(types, abis, bins, sigs, c.String(pkgFlag.Name), libs, aliases)
 	}