Add file (line/col) info to ref/relref errors

See #5371

7 files changed, 236 insertions, 151 deletions

diff --git a/common/herrors/error_locator.go b/common/herrors/error_locator.go
index 5d3f079be..88cb06c8c 100644
--- a/common/herrors/error_locator.go
+++ b/common/herrors/error_locator.go
@@ -15,72 +15,21 @@
 package herrors
 
 import (
-	"fmt"
 	"io"
 	"io/ioutil"
-	"os"
 	"strings"
 
-	"github.com/gohugoio/hugo/common/terminal"
+	"github.com/gohugoio/hugo/common/text"
 	"github.com/gohugoio/hugo/helpers"
 
 	"github.com/spf13/afero"
 )
 
-var fileErrorFormatFunc func(e ErrorContext) string
-
-func createFileLogFormatter(formatStr string) func(e ErrorContext) string {
-
-	if formatStr == "" {
-		formatStr = "\":file::line::col\""
-	}
-
-	var identifiers = []string{":file", ":line", ":col"}
-	var identifiersFound []string
-
-	for i := range formatStr {
-		for _, id := range identifiers {
-			if strings.HasPrefix(formatStr[i:], id) {
-				identifiersFound = append(identifiersFound, id)
-			}
-		}
-	}
-
-	replacer := strings.NewReplacer(":file", "%s", ":line", "%d", ":col", "%d")
-	format := replacer.Replace(formatStr)
-
-	f := func(e ErrorContext) string {
-		args := make([]interface{}, len(identifiersFound))
-		for i, id := range identifiersFound {
-			switch id {
-			case ":file":
-				args[i] = e.Filename
-			case ":line":
-				args[i] = e.LineNumber
-			case ":col":
-				args[i] = e.ColumnNumber
-			}
-		}
-
-		msg := fmt.Sprintf(format, args...)
-
-		if terminal.IsTerminal(os.Stdout) {
-			return terminal.Notice(msg)
-		}
-
-		return msg
-	}
-
-	return f
-}
-
-func init() {
-	fileErrorFormatFunc = createFileLogFormatter(os.Getenv("HUGO_FILE_LOG_FORMAT"))
-}
-
 // LineMatcher contains the elements used to match an error to a line
 type LineMatcher struct {
-	FileError  FileError
+	Position text.Position
+	Error    error
+
 	LineNumber int
 	Offset     int
 	Line       string
@@ -91,33 +40,34 @@ type LineMatcherFn func(m LineMatcher) bool
 
 // SimpleLineMatcher simply matches by line number.
 var SimpleLineMatcher = func(m LineMatcher) bool {
-	return m.FileError.LineNumber() == m.LineNumber
+	return m.Position.LineNumber == m.LineNumber
 }
 
+var _ text.Positioner = ErrorContext{}
+
 // ErrorContext contains contextual information about an error. This will
 // typically be the lines surrounding some problem in a file.
 type ErrorContext struct {
-	// The source filename.
-	Filename string
 
 	// If a match will contain the matched line and up to 2 lines before and after.
 	// Will be empty if no match.
 	Lines []string
 
 	// The position of the error in the Lines above. 0 based.
-	Pos int
-
-	// The linenumber in the source file from where the Lines start. Starting at 1.
-	LineNumber int
+	LinesPos int
 
-	// The column number in the source file. Starting at 1.
-	ColumnNumber int
+	position text.Position
 
 	// The lexer to use for syntax highlighting.
 	// https://gohugo.io/content-management/syntax-highlighting/#list-of-chroma-highlighting-languages
 	ChromaLexer string
 }
 
+// Position returns the text position of this error.
+func (e ErrorContext) Position() text.Position {
+	return e.position
+}
+
 var _ causer = (*ErrorWithFileContext)(nil)
 
 // ErrorWithFileContext is an error with some additional file context related
@@ -128,7 +78,11 @@ type ErrorWithFileContext struct {
 }
 
 func (e *ErrorWithFileContext) Error() string {
-	return fileErrorFormatFunc(e.ErrorContext) + ": " + e.cause.Error()
+	pos := e.Position()
+	if pos.IsValid() {
+		return pos.String() + ": " + e.cause.Error()
+	}
+	return e.cause.Error()
 }
 
 func (e *ErrorWithFileContext) Cause() error {
@@ -163,24 +117,27 @@ func WithFileContext(e error, realFilename string, r io.Reader, matcher LineMatc
 
 	var errCtx ErrorContext
 
-	if le.Offset() != -1 {
+	posle := le.Position()
+
+	if posle.Offset != -1 {
 		errCtx = locateError(r, le, func(m LineMatcher) bool {
-			if le.Offset() >= m.Offset && le.Offset() < m.Offset+len(m.Line) {
-				fe := m.FileError
-				m.FileError = ToFileErrorWithOffset(fe, -fe.LineNumber()+m.LineNumber)
+			if posle.Offset >= m.Offset && posle.Offset < m.Offset+len(m.Line) {
+				lno := posle.LineNumber - m.Position.LineNumber + m.LineNumber
+				m.Position = text.Position{LineNumber: lno}
 			}
 			return matcher(m)
 		})
-
 	} else {
 		errCtx = locateError(r, le, matcher)
 	}
 
-	if errCtx.LineNumber == -1 {
+	pos := &errCtx.position
+
+	if pos.LineNumber == -1 {
 		return e, false
 	}
 
-	errCtx.Filename = realFilename
+	pos.Filename = realFilename
 
 	if le.Type() != "" {
 		errCtx.ChromaLexer = chromaLexerFromType(le.Type())
@@ -233,17 +190,20 @@ func locateError(r io.Reader, le FileError, matches LineMatcherFn) ErrorContext
 		panic("must provide an error")
 	}
 
-	errCtx := ErrorContext{LineNumber: -1, ColumnNumber: 1, Pos: -1}
+	errCtx := ErrorContext{position: text.Position{LineNumber: -1, ColumnNumber: 1, Offset: -1}, LinesPos: -1}
 
 	b, err := ioutil.ReadAll(r)
 	if err != nil {
 		return errCtx
 	}
 
+	pos := &errCtx.position
+	lepos := le.Position()
+
 	lines := strings.Split(string(b), "\n")
 
-	if le != nil && le.ColumnNumber() >= 0 {
-		errCtx.ColumnNumber = le.ColumnNumber()
+	if le != nil && lepos.ColumnNumber >= 0 {
+		pos.ColumnNumber = lepos.ColumnNumber
 	}
 
 	lineNo := 0
@@ -252,32 +212,33 @@ func locateError(r io.Reader, le FileError, matches LineMatcherFn) ErrorContext
 	for li, line := range lines {
 		lineNo = li + 1
 		m := LineMatcher{
-			FileError:  le,
+			Position:   le.Position(),
+			Error:      le,
 			LineNumber: lineNo,
 			Offset:     posBytes,
 			Line:       line,
 		}
-		if errCtx.Pos == -1 && matches(m) {
-			errCtx.LineNumber = lineNo
+		if errCtx.LinesPos == -1 && matches(m) {
+			pos.LineNumber = lineNo
 			break
 		}
 
 		posBytes += len(line)
 	}
 
-	if errCtx.LineNumber != -1 {
-		low := errCtx.LineNumber - 3
+	if pos.LineNumber != -1 {
+		low := pos.LineNumber - 3
 		if low < 0 {
 			low = 0
 		}
 
-		if errCtx.LineNumber > 2 {
-			errCtx.Pos = 2
+		if pos.LineNumber > 2 {
+			errCtx.LinesPos = 2
 		} else {
-			errCtx.Pos = errCtx.LineNumber - 1
+			errCtx.LinesPos = pos.LineNumber - 1
 		}
 
-		high := errCtx.LineNumber + 2
+		high := pos.LineNumber + 2
 		if high > len(lines) {
 			high = len(lines)
 		}
diff --git a/common/herrors/error_locator_test.go b/common/herrors/error_locator_test.go
index 84c0faf89..2d007016d 100644
--- a/common/herrors/error_locator_test.go
+++ b/common/herrors/error_locator_test.go
@@ -21,18 +21,6 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func TestCreateFileLogFormatter(t *testing.T) {
-	assert := require.New(t)
-
-	ctx := ErrorContext{Filename: "/my/file.txt", LineNumber: 12, ColumnNumber: 13}
-
-	assert.Equal("/my/file.txt|13|12", createFileLogFormatter(":file|:col|:line")(ctx))
-	assert.Equal("13|/my/file.txt|12", createFileLogFormatter(":col|:file|:line")(ctx))
-	assert.Equal("好:13", createFileLogFormatter("好::col")(ctx))
-	assert.Equal("\"/my/file.txt:12:13\"", createFileLogFormatter("")(ctx))
-
-}
-
 func TestErrorLocator(t *testing.T) {
 	assert := require.New(t)
 
@@ -53,8 +41,9 @@ LINE 8
 	location := locateErrorInString(lines, lineMatcher)
 	assert.Equal([]string{"LINE 3", "LINE 4", "This is THEONE", "LINE 6", "LINE 7"}, location.Lines)
 
-	assert.Equal(5, location.LineNumber)
-	assert.Equal(2, location.Pos)
+	pos := location.Position()
+	assert.Equal(5, pos.LineNumber)
+	assert.Equal(2, location.LinesPos)
 
 	assert.Equal([]string{"This is THEONE"}, locateErrorInString(`This is THEONE`, lineMatcher).Lines)
 
@@ -62,32 +51,32 @@ LINE 8
 This is THEONE
 L2
 `, lineMatcher)
-	assert.Equal(2, location.LineNumber)
-	assert.Equal(1, location.Pos)
+	assert.Equal(2, location.Position().LineNumber)
+	assert.Equal(1, location.LinesPos)
 	assert.Equal([]string{"L1", "This is THEONE", "L2", ""}, location.Lines)
 
 	location = locateErrorInString(`This is THEONE
 L2
 `, lineMatcher)
-	assert.Equal(0, location.Pos)
+	assert.Equal(0, location.LinesPos)
 	assert.Equal([]string{"This is THEONE", "L2", ""}, location.Lines)
 
 	location = locateErrorInString(`L1
 This THEONE
 `, lineMatcher)
 	assert.Equal([]string{"L1", "This THEONE", ""}, location.Lines)
-	assert.Equal(1, location.Pos)
+	assert.Equal(1, location.LinesPos)
 
 	location = locateErrorInString(`L1
 L2
 This THEONE
 `, lineMatcher)
 	assert.Equal([]string{"L1", "L2", "This THEONE", ""}, location.Lines)
-	assert.Equal(2, location.Pos)
+	assert.Equal(2, location.LinesPos)
 
 	location = locateErrorInString("NO MATCH", lineMatcher)
-	assert.Equal(-1, location.LineNumber)
-	assert.Equal(-1, location.Pos)
+	assert.Equal(-1, location.Position().LineNumber)
+	assert.Equal(-1, location.LinesPos)
 	assert.Equal(0, len(location.Lines))
 
 	lineMatcher = func(m LineMatcher) bool {
@@ -106,8 +95,8 @@ I
 J`, lineMatcher)
 
 	assert.Equal([]string{"D", "E", "F", "G", "H"}, location.Lines)
-	assert.Equal(6, location.LineNumber)
-	assert.Equal(2, location.Pos)
+	assert.Equal(6, location.Position().LineNumber)
+	assert.Equal(2, location.LinesPos)
 
 	// Test match EOF
 	lineMatcher = func(m LineMatcher) bool {
@@ -120,8 +109,8 @@ C
 `, lineMatcher)
 
 	assert.Equal([]string{"B", "C", ""}, location.Lines)
-	assert.Equal(4, location.LineNumber)
-	assert.Equal(2, location.Pos)
+	assert.Equal(4, location.Position().LineNumber)
+	assert.Equal(2, location.LinesPos)
 
 	offsetMatcher := func(m LineMatcher) bool {
 		return m.Offset == 1
@@ -134,7 +123,7 @@ D
 E`, offsetMatcher)
 
 	assert.Equal([]string{"A", "B", "C", "D"}, location.Lines)
-	assert.Equal(2, location.LineNumber)
-	assert.Equal(1, location.Pos)
+	assert.Equal(2, location.Position().LineNumber)
+	assert.Equal(1, location.LinesPos)
 
 }
diff --git a/common/herrors/file_error.go b/common/herrors/file_error.go
index 49b9f808a..929cc800f 100644
--- a/common/herrors/file_error.go
+++ b/common/herrors/file_error.go
@@ -16,25 +16,21 @@ package herrors
 import (
 	"encoding/json"
 
+	"github.com/gohugoio/hugo/common/text"
+
 	"github.com/pkg/errors"
 )
 
-var _ causer = (*fileError)(nil)
+var (
+	_ causer = (*fileError)(nil)
+)
 
 // FileError represents an error when handling a file: Parsing a config file,
 // execute a template etc.
 type FileError interface {
 	error
 
-	// Offset gets the error location offset in bytes, starting at 0.
-	// It will return -1 if not provided.
-	Offset() int
-
-	// LineNumber gets the error location, starting at line 1.
-	LineNumber() int
-
-	// Column number gets the column location, starting at 1.
-	ColumnNumber() int
+	text.Positioner
 
 	// A string identifying the type of file, e.g. JSON, TOML, markdown etc.
 	Type() string
@@ -43,33 +39,16 @@ type FileError interface {
 var _ FileError = (*fileError)(nil)
 
 type fileError struct {
-	offset       int
-	lineNumber   int
-	columnNumber int
-	fileType     string
-
-	cause error
-}
+	position text.Position
 
-type fileErrorWithLineOffset struct {
-	FileError
-	offset int
-}
-
-func (e *fileErrorWithLineOffset) LineNumber() int {
-	return e.FileError.LineNumber() + e.offset
-}
+	fileType string
 
-func (e *fileError) LineNumber() int {
-	return e.lineNumber
-}
-
-func (e *fileError) Offset() int {
-	return e.offset
+	cause error
 }
 
-func (e *fileError) ColumnNumber() int {
-	return e.columnNumber
+// Position returns the text position of this error.
+func (e fileError) Position() text.Position {
+	return e.position
 }
 
 func (e *fileError) Type() string {
@@ -89,7 +68,8 @@ func (f *fileError) Cause() error {
 
 // NewFileError creates a new FileError.
 func NewFileError(fileType string, offset, lineNumber, columnNumber int, err error) FileError {
-	return &fileError{cause: err, fileType: fileType, offset: offset, lineNumber: lineNumber, columnNumber: columnNumber}
+	pos := text.Position{Offset: offset, LineNumber: lineNumber, ColumnNumber: columnNumber}
+	return &fileError{cause: err, fileType: fileType, position: pos}
 }
 
 // UnwrapFileError tries to unwrap a FileError from err.
@@ -111,7 +91,9 @@ func UnwrapFileError(err error) FileError {
 // ToFileErrorWithOffset will return a new FileError with a line number
 // with the given offset from the original.
 func ToFileErrorWithOffset(fe FileError, offset int) FileError {
-	return &fileErrorWithLineOffset{FileError: fe, offset: offset}
+	pos := fe.Position()
+	pos.LineNumber = pos.LineNumber + offset
+	return &fileError{cause: fe, fileType: fe.Type(), position: pos}
 }
 
 // ToFileError will convert the given error to an error supporting
@@ -123,6 +105,7 @@ func ToFileError(fileType string, err error) FileError {
 		if fileType == "" {
 			fileType = typ
 		}
+
 		if lno > 0 || offset != -1 {
 			return NewFileError(fileType, offset, lno, col, err)
 		}
diff --git a/common/herrors/file_error_test.go b/common/herrors/file_error_test.go
index 6acb49603..4108983d3 100644
--- a/common/herrors/file_error_test.go
+++ b/common/herrors/file_error_test.go
@@ -42,17 +42,15 @@ func TestToLineNumberError(t *testing.T) {
 	} {
 
 		got := ToFileError("template", test.in)
-		if test.offset > 0 {
-			got = ToFileErrorWithOffset(got.(FileError), test.offset)
-		}
 
 		errMsg := fmt.Sprintf("[%d][%T]", i, got)
 		le, ok := got.(FileError)
 		assert.True(ok)
 
 		assert.True(ok, errMsg)
-		assert.Equal(test.lineNumber, le.LineNumber(), errMsg)
-		assert.Equal(test.columnNumber, le.ColumnNumber(), errMsg)
+		pos := le.Position()
+		assert.Equal(test.lineNumber, pos.LineNumber, errMsg)
+		assert.Equal(test.columnNumber, pos.ColumnNumber, errMsg)
 		assert.Error(errors.Cause(got))
 	}
 
diff --git a/common/text/position.go b/common/text/position.go
new file mode 100644
index 000000000..0c43c5ae7
--- /dev/null
+++ b/common/text/position.go
@@ -0,0 +1,99 @@
+// Copyright 2018 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package text
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/gohugoio/hugo/common/terminal"
+)
+
+// Positioner represents a thing that knows its position in a text file or stream,
+// typically an error.
+type Positioner interface {
+	Position() Position
+}
+
+// Position holds a source position in a text file or stream.
+type Position struct {
+	Filename     string // filename, if any
+	Offset       int    // byte offset, starting at 0. It's set to -1 if not provided.
+	LineNumber   int    // line number, starting at 1
+	ColumnNumber int    // column number, starting at 1 (character count per line)
+}
+
+func (pos Position) String() string {
+	if pos.Filename == "" {
+		pos.Filename = "<stream>"
+	}
+	return positionStringFormatfunc(pos)
+}
+
+// IsValid returns true if line number is > 0.
+func (pos Position) IsValid() bool {
+	return pos.LineNumber > 0
+}
+
+var positionStringFormatfunc func(p Position) string
+
+func createPositionStringFormatter(formatStr string) func(p Position) string {
+
+	if formatStr == "" {
+		formatStr = "\":file::line::col\""
+	}
+
+	var identifiers = []string{":file", ":line", ":col"}
+	var identifiersFound []string
+
+	for i := range formatStr {
+		for _, id := range identifiers {
+			if strings.HasPrefix(formatStr[i:], id) {
+				identifiersFound = append(identifiersFound, id)
+			}
+		}
+	}
+
+	replacer := strings.NewReplacer(":file", "%s", ":line", "%d", ":col", "%d")
+	format := replacer.Replace(formatStr)
+
+	f := func(pos Position) string {
+		args := make([]interface{}, len(identifiersFound))
+		for i, id := range identifiersFound {
+			switch id {
+			case ":file":
+				args[i] = pos.Filename
+			case ":line":
+				args[i] = pos.LineNumber
+			case ":col":
+				args[i] = pos.ColumnNumber
+			}
+		}
+
+		msg := fmt.Sprintf(format, args...)
+
+		if terminal.IsTerminal(os.Stdout) {
+			return terminal.Notice(msg)
+		}
+
+		return msg
+	}
+
+	return f
+}
+
+func init() {
+	positionStringFormatfunc = createPositionStringFormatter(os.Getenv("HUGO_FILE_LOG_FORMAT"))
+}
diff --git a/common/text/position_test.go b/common/text/position_test.go
new file mode 100644
index 000000000..a25a3edbd
--- /dev/null
+++ b/common/text/position_test.go
@@ -0,0 +1,33 @@
+// Copyright 2018 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package text
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPositionStringFormatter(t *testing.T) {
+	assert := require.New(t)
+
+	pos := Position{Filename: "/my/file.txt", LineNumber: 12, ColumnNumber: 13, Offset: 14}
+
+	assert.Equal("/my/file.txt|13|12", createPositionStringFormatter(":file|:col|:line")(pos))
+	assert.Equal("13|/my/file.txt|12", createPositionStringFormatter(":col|:file|:line")(pos))
+	assert.Equal("好:13", createPositionStringFormatter("好::col")(pos))
+	assert.Equal("\"/my/file.txt:12:13\"", createPositionStringFormatter("")(pos))
+	assert.Equal("\"/my/file.txt:12:13\"", pos.String())
+
+}
diff --git a/common/urls/ref.go b/common/urls/ref.go
new file mode 100644
index 000000000..71b00b71d
--- /dev/null
+++ b/common/urls/ref.go
@@ -0,0 +1,22 @@
+// Copyright 2018 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package urls
+
+// RefLinker is implemented by those who support reference linking.
+// args must contain a path, but can also point to the target
+// language or output format.
+type RefLinker interface {
+	Ref(args map[string]interface{}) (string, error)
+	RelRef(args map[string]interface{}) (string, error)
+}