Merge pull request #4 from moznion/support_caused_at

Support `caused at` on error message

Makefile

@@ -43,5 +43,5 @@ bootstrap: installdeps
 		github.com/moznion/go-errgen/cmd/errgen
 
 errgen:
-	./author/errgen.sh
+	go generate ./...
 

README.md

@@ -74,6 +74,16 @@ Please refer to the godoc: [![GoDoc](https://godoc.org/github.com/moznion/gowrtr
 
 Methods of this library act as immutable. It means it doesn't change any internal state implicitly, so you can take a snapshot of the code generator. That is useful to reuse and derive the code generator instance.
 
+### Debug friendly
+
+This library shows "where is a cause of the error" when code generator raises an error. This means each error message contains a pointer for the error source (i.e. file name and the line number).  This should be helpful for debugging.
+
+Error messages example:
+
+```
+[GOWRTR-14] condition of case must not be empty, but it gets empty (caused at /tmp/main.go:22)
+```
+
 ### Supported syntax
 
 - [x] `package`

generator/anonymous_func.go

@@ -1,13 +1,16 @@
 package generator
 
-import "github.com/moznion/gowrtr/internal/errmsg"
+import (
+	"github.com/moznion/gowrtr/internal/errmsg"
+)
 
 // AnonymousFunc represents a code generator for anonymous func.
 type AnonymousFunc struct {
 	goFunc                 bool
 	anonymousFuncSignature *AnonymousFuncSignature
 	statements             []Statement
 	funcInvocation         *FuncInvocation
+	caller                 string
 }
 
 // NewAnonymousFunc returns a new `AnonymousFunc`.
@@ -17,6 +20,7 @@ func NewAnonymousFunc(goFunc bool, signature *AnonymousFuncSignature, statements
 		goFunc:                 goFunc,
 		anonymousFuncSignature: signature,
 		statements:             statements,
+		caller:                 fetchClientCallerLine(),
 	}
 }
 
@@ -28,6 +32,7 @@ func (ifg *AnonymousFunc) AddStatements(statements ...Statement) *AnonymousFunc
 		anonymousFuncSignature: ifg.anonymousFuncSignature,
 		statements:             append(ifg.statements, statements...),
 		funcInvocation:         ifg.funcInvocation,
+		caller:                 ifg.caller,
 	}
 }
 
@@ -39,6 +44,7 @@ func (ifg *AnonymousFunc) Statements(statements ...Statement) *AnonymousFunc {
 		anonymousFuncSignature: ifg.anonymousFuncSignature,
 		statements:             statements,
 		funcInvocation:         ifg.funcInvocation,
+		caller:                 ifg.caller,
 	}
 }
 
@@ -50,6 +56,7 @@ func (ifg *AnonymousFunc) Invocation(funcInvocation *FuncInvocation) *AnonymousF
 		anonymousFuncSignature: ifg.anonymousFuncSignature,
 		statements:             ifg.statements,
 		funcInvocation:         funcInvocation,
+		caller:                 ifg.caller,
 	}
 }
 
@@ -64,7 +71,7 @@ func (ifg *AnonymousFunc) Generate(indentLevel int) (string, error) {
 	stmt += "func"
 
 	if ifg.anonymousFuncSignature == nil {
-		return "", errmsg.AnonymousFuncSignatureIsNilError()
+		return "", errmsg.AnonymousFuncSignatureIsNilError(ifg.caller)
 	}
 
 	sig, err := ifg.anonymousFuncSignature.Generate(0)

generator/anonymous_func_signature.go

@@ -10,6 +10,7 @@ import (
 type AnonymousFuncSignature struct {
 	funcParameters []*FuncParameter
 	returnTypes    []string
+	callers        []string
 }
 
 // NewAnonymousFuncSignature returns a new `AnonymousFuncSignature`.
@@ -23,6 +24,7 @@ func (f *AnonymousFuncSignature) AddParameters(funcParameters ...*FuncParameter)
 	return &AnonymousFuncSignature{
 		funcParameters: append(f.funcParameters, funcParameters...),
 		returnTypes:    f.returnTypes,
+		callers:        append(f.callers, fetchClientCallerLineAsSlice(len(funcParameters))...),
 	}
 }
 
@@ -32,6 +34,7 @@ func (f *AnonymousFuncSignature) Parameters(funcParameters ...*FuncParameter) *A
 	return &AnonymousFuncSignature{
 		funcParameters: funcParameters,
 		returnTypes:    f.returnTypes,
+		callers:        fetchClientCallerLineAsSlice(len(funcParameters)),
 	}
 }
 
@@ -41,6 +44,7 @@ func (f *AnonymousFuncSignature) AddReturnTypes(returnTypes ...string) *Anonymou
 	return &AnonymousFuncSignature{
 		funcParameters: f.funcParameters,
 		returnTypes:    append(f.returnTypes, returnTypes...),
+		callers:        f.callers,
 	}
 }
 
@@ -50,6 +54,7 @@ func (f *AnonymousFuncSignature) ReturnTypes(returnTypes ...string) *AnonymousFu
 	return &AnonymousFuncSignature{
 		funcParameters: f.funcParameters,
 		returnTypes:    returnTypes,
+		callers:        f.callers,
 	}
 }
 
@@ -58,22 +63,26 @@ func (f *AnonymousFuncSignature) Generate(indentLevel int) (string, error) {
 	stmt := "("
 
 	typeExisted := true
+	typeMissingCaller := ""
 	params := make([]string, len(f.funcParameters))
 	for i, param := range f.funcParameters {
 		if param.name == "" {
-			return "", errmsg.FuncParameterNameIsEmptyErr()
+			return "", errmsg.FuncParameterNameIsEmptyErr(f.callers[i])
 		}
 
 		paramSet := param.name
 		typeExisted = param.typ != ""
 		if typeExisted {
 			paramSet += " " + param.typ
 		}
+		if !typeExisted {
+			typeMissingCaller = f.callers[i]
+		}
 		params[i] = paramSet
 	}
 
 	if !typeExisted {
-		return "", errmsg.LastFuncParameterTypeIsEmptyErr()
+		return "", errmsg.LastFuncParameterTypeIsEmptyErr(typeMissingCaller)
 	}
 
 	stmt += strings.Join(params, ", ") + ")"

generator/anonymous_func_signature_test.go

@@ -1,6 +1,8 @@
 package generator
 
 import (
+	"regexp"
+	"strings"
 	"testing"
 
 	"github.com/moznion/gowrtr/internal/errmsg"
@@ -41,13 +43,17 @@ func TestShouldGenerateAnonymousFuncSignatureRaisesErrorWhenParamNameIsEmpty(t *
 		NewFuncParameter("", "string"),
 	)
 	_, err := generator.Generate(0)
-	assert.EqualError(t, err, errmsg.FuncParameterNameIsEmptyErr().Error())
+	assert.Regexp(t, regexp.MustCompile(
+		`^\`+strings.Split(errmsg.FuncParameterNameIsEmptyErr("").Error(), " ")[0],
+	), err.Error())
 }
 
 func TestShouldGenerateAnonymousFuncSignatureRaisesErrorWhenParamTypeIsEmpty(t *testing.T) {
 	generator := NewAnonymousFuncSignature().AddParameters(
 		NewFuncParameter("foo", ""),
 	)
 	_, err := generator.Generate(0)
-	assert.EqualError(t, err, errmsg.LastFuncParameterTypeIsEmptyErr().Error())
+	assert.Regexp(t, regexp.MustCompile(
+		`^\`+strings.Split(errmsg.LastFuncParameterTypeIsEmptyErr("").Error(), " ")[0],
+	), err.Error())
 }

generator/anonymous_func_test.go

@@ -1,6 +1,8 @@
 package generator
 
 import (
+	"regexp"
+	"strings"
 	"testing"
 
 	"github.com/moznion/gowrtr/internal/errmsg"
@@ -117,7 +119,9 @@ func TestShouldGenerateAnonymousFuncRaisesErrorWhenAnonymousFuncSignatureIsNil(t
 		nil,
 	)
 	_, err := generator.Generate(0)
-	assert.EqualError(t, err, errmsg.AnonymousFuncSignatureIsNilError().Error())
+	assert.Regexp(t, regexp.MustCompile(
+		`^\`+strings.Split(errmsg.AnonymousFuncSignatureIsNilError("").Error(), " ")[0],
+	), err.Error())
 }
 
 func TestShouldGenerateAnonymousFuncRaisesErrorWhenAnonymousFuncSignatureRaisesError(t *testing.T) {
@@ -128,7 +132,9 @@ func TestShouldGenerateAnonymousFuncRaisesErrorWhenAnonymousFuncSignatureRaisesE
 		),
 	)
 	_, err := generator.Generate(0)
-	assert.EqualError(t, err, errmsg.FuncParameterNameIsEmptyErr().Error())
+	assert.Regexp(t, regexp.MustCompile(
+		`^\`+strings.Split(errmsg.FuncParameterNameIsEmptyErr("").Error(), " ")[0],
+	), err.Error())
 }
 
 func TestShouldGenerateAnonymousFuncRaisesErrorWhenStatementRaisesError(t *testing.T) {
@@ -139,7 +145,9 @@ func TestShouldGenerateAnonymousFuncRaisesErrorWhenStatementRaisesError(t *testi
 	)
 
 	_, err := generator.Generate(0)
-	assert.EqualError(t, err, errmsg.FuncNameIsEmptyError().Error())
+	assert.Regexp(t, regexp.MustCompile(
+		`^\`+strings.Split(errmsg.FuncNameIsEmptyError("").Error(), " ")[0],
+	), err.Error())
 }
 
 func TestShouldGenerateAnonymousFuncRaisesErrorWhenFuncInvocationRaisesError(t *testing.T) {
@@ -148,5 +156,7 @@ func TestShouldGenerateAnonymousFuncRaisesErrorWhenFuncInvocationRaisesError(t *
 		NewAnonymousFuncSignature(),
 	).Invocation(NewFuncInvocation(""))
 	_, err := generator.Generate(0)
-	assert.EqualError(t, err, errmsg.FuncInvocationParameterIsEmptyError().Error())
+	assert.Regexp(t, regexp.MustCompile(
+		`^\`+strings.Split(errmsg.FuncInvocationParameterIsEmptyError("").Error(), " ")[0],
+	), err.Error())
 }

generator/case.go

@@ -11,13 +11,15 @@ import (
 type Case struct {
 	condition  string
 	statements []Statement
+	caller     string
 }
 
 // NewCase creates a new `Case`.
 func NewCase(condition string, statements ...Statement) *Case {
 	return &Case{
 		condition:  condition,
 		statements: statements,
+		caller:     fetchClientCallerLine(),
 	}
 }
 
@@ -43,7 +45,7 @@ func (c *Case) Statements(statements ...Statement) *Case {
 func (c *Case) Generate(indentLevel int) (string, error) {
 	condition := c.condition
 	if condition == "" {
-		return "", errmsg.CaseConditionIsEmptyError()
+		return "", errmsg.CaseConditionIsEmptyError(c.caller)
 	}
 
 	indent := buildIndent(indentLevel)

generator/case_test.go

@@ -1,6 +1,8 @@
 package generator
 
 import (
+	"regexp"
+	"strings"
 	"testing"
 
 	"github.com/moznion/gowrtr/internal/errmsg"
@@ -51,7 +53,9 @@ func TestShouldGenerateCase(t *testing.T) {
 func TestShouldGenerateCaseRaisesErrorWhenConditionIsEmpty(t *testing.T) {
 	generator := NewCase("")
 	_, err := generator.Generate(0)
-	assert.EqualError(t, err, errmsg.CaseConditionIsEmptyError().Error())
+	assert.Regexp(t, regexp.MustCompile(
+		`^\`+strings.Split(errmsg.CaseConditionIsEmptyError("").Error(), " ")[0],
+	), err.Error())
 }
 
 func TestShouldGenerateCaseRaisesErrorWhenStatementsRaisesError(t *testing.T) {
@@ -60,5 +64,7 @@ func TestShouldGenerateCaseRaisesErrorWhenStatementsRaisesError(t *testing.T) {
 		NewFunc(nil, NewFuncSignature("")),
 	)
 	_, err := generator.Generate(0)
-	assert.EqualError(t, err, errmsg.FuncNameIsEmptyError().Error())
+	assert.Regexp(t, regexp.MustCompile(
+		`^\`+strings.Split(errmsg.FuncNameIsEmptyError("").Error(), " ")[0],
+	), err.Error())
 }

generator/code_block_test.go

@@ -1,6 +1,8 @@
 package generator
 
 import (
+	"regexp"
+	"strings"
 	"testing"
 
 	"github.com/moznion/gowrtr/internal/errmsg"
@@ -94,5 +96,7 @@ func TestShouldGenerateCodeBlockGiveUpWhenStatementRaisesError(t *testing.T) {
 		NewFunc(nil, NewFuncSignature("")),
 	)
 	_, err := generator.Generate(0)
-	assert.EqualError(t, err, errmsg.FuncNameIsEmptyError().Error())
+	assert.Regexp(t, regexp.MustCompile(
+		`^\`+strings.Split(errmsg.FuncNameIsEmptyError("").Error(), " ")[0],
+	), err.Error())
 }

generator/composite_literal.go

@@ -15,8 +15,9 @@ type compositeLiteralField struct {
 // CompositeLiteral represents a code generator for composite literal.
 // Please see also: https://golang.org/doc/effective_go.html#composite_literals
 type CompositeLiteral struct {
-	typ    string
-	fields []*compositeLiteralField
+	typ     string
+	fields  []*compositeLiteralField
+	callers []string
 }
 
 // NewCompositeLiteral returns a new `CompositeLiteral`.
@@ -35,6 +36,7 @@ func (c *CompositeLiteral) AddField(key string, value Statement) *CompositeLiter
 			key:   key,
 			value: value,
 		}),
+		callers: append(c.callers, fetchClientCallerLine()),
 	}
 }
 
@@ -47,6 +49,7 @@ func (c *CompositeLiteral) AddFieldStr(key string, value string) *CompositeLiter
 			key:   key,
 			value: NewRawStatement(fmt.Sprintf(`"%s"`, value)),
 		}),
+		callers: append(c.callers, fetchClientCallerLine()),
 	}
 }
 
@@ -59,6 +62,7 @@ func (c *CompositeLiteral) AddFieldRaw(key string, value interface{}) *Composite
 			key:   key,
 			value: NewRawStatement(fmt.Sprintf("%v", value)),
 		}),
+		callers: append(c.callers, fetchClientCallerLine()),
 	}
 }
 
@@ -68,7 +72,7 @@ func (c *CompositeLiteral) Generate(indentLevel int) (string, error) {
 	nextLevelIndent := buildIndent(indentLevel + 1)
 
 	stmt := fmt.Sprintf("%s%s{\n", indent, c.typ)
-	for _, field := range c.fields {
+	for i, field := range c.fields {
 		genValue, err := field.value.Generate(indentLevel + 1)
 		if err != nil {
 			return "", err
@@ -82,7 +86,7 @@ func (c *CompositeLiteral) Generate(indentLevel int) (string, error) {
 			stmt += key + ": "
 		}
 		if genValue == "" {
-			return "", errmsg.ValueOfCompositeLiteralIsEmptyError()
+			return "", errmsg.ValueOfCompositeLiteralIsEmptyError(c.callers[i])
 		}
 		stmt += fmt.Sprintf("%s,\n", genValue)
 	}

generator/composite_literal_test.go

@@ -1,6 +1,8 @@
 package generator
 
 import (
+	"regexp"
+	"strings"
 	"testing"
 
 	"github.com/moznion/gowrtr/internal/errmsg"
@@ -73,10 +75,14 @@ func TestShouldGenerateCompositeLiteralWithEmptyKey(t *testing.T) {
 
 func TestShouldGenerateCompositeLiteralRaiseError(t *testing.T) {
 	_, err := NewCompositeLiteral("").AddField("foo", NewIf("")).Generate(0)
-	assert.EqualError(t, err, errmsg.IfConditionIsEmptyError().Error())
+	assert.Regexp(t, regexp.MustCompile(
+		`^\`+strings.Split(errmsg.IfConditionIsEmptyError("").Error(), " ")[0],
+	), err.Error())
 }
 
 func TestShouldGenerateCompositeLiteralRaiseErrorWhenValueIsEmpty(t *testing.T) {
 	_, err := NewCompositeLiteral("[]string").AddField("foo", NewRawStatement("")).Generate(0)
-	assert.EqualError(t, err, errmsg.ValueOfCompositeLiteralIsEmptyError().Error())
+	assert.Regexp(t, regexp.MustCompile(
+		`^\`+strings.Split(errmsg.ValueOfCompositeLiteralIsEmptyError("").Error(), " ")[0],
+	), err.Error())
 }