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compiler: export cycleError implementing the CompilerError interface
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This change renames the cycleError type to CycleError and makes it
implement the CompilerError interface.
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@gazerro
gazerro authored Sep 9, 2020
1 parent a702149 commit ff0b4ea
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Showing 4 changed files with 215 additions and 52 deletions.
28 changes: 24 additions & 4 deletions compiler/parser.go
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Original file line number Diff line number Diff line change
Expand Up @@ -72,11 +72,31 @@ func syntaxError(pos *ast.Position, format string, a ...interface{}) *SyntaxErro
return &SyntaxError{"", *pos, fmt.Sprintf(format, a...)}
}

// cycleError implements an error indicating the presence of a cycle.
type cycleError string
// CycleError implements an error indicating the presence of a cycle.
type CycleError struct {
path string
pos ast.Position
msg string
}

func (e *CycleError) Error() string {
return e.msg
}

func (e cycleError) Error() string {
return string(e)
// Path returns the path of the first referenced file in the cycle.
func (e *CycleError) Path() string {
return e.path
}

// Position returns the position of the extends, import or show statement
// referring the second file in the cycle.
func (e *CycleError) Position() ast.Position {
return e.pos
}

// Message returns the message of cycle error, without position and path.
func (e *CycleError) Message() string {
return e.msg
}

// containsOnlySpaces reports whether b contains only white space characters
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196 changes: 163 additions & 33 deletions compiler/parser_cycle_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -14,49 +14,179 @@ import (
"github.com/google/go-cmp/cmp"
)

var cyclicProgram = mapStringLoader{
"main": "package main\nimport _ \"cycle/foo\"\nfunc main() {}",
"cycle/foo": "package foo\nimport _ \"cycle/foo2\"",
"cycle/foo2": "package foo2\nimport _ \"cycle/foo3\"",
"cycle/foo3": "package foo3\nimport _ \"cycle/foo\"",
}
var cycleProgramTests = []struct {
name string
program mapStringLoader
path string
pos ast.Position
msg string
}{

const cyclicProgramErrorMessage = `package main
{
name: "Package import cycle",
program: mapStringLoader{
"main": "package main\nimport _ \"cycle/foo\"\nfunc main() {}",
"cycle/foo": "package foo\nimport _ \"cycle/foo2\"",
"cycle/foo2": "package foo2\nimport _ \"cycle/foo3\"",
"cycle/foo3": "package foo3\nimport _ \"cycle/foo\"",
},
path: "cycle/foo",
pos: ast.Position{Line: 2, Column: 8, Start: 20, End: 32},
msg: `package main
imports cycle/foo
imports cycle/foo2
imports cycle/foo3
imports cycle/foo: import cycle not allowed`
imports cycle/foo: import cycle not allowed`,
},

func TestCyclicProgram(t *testing.T) {
_, err := ParseProgram(cyclicProgram)
if err == nil {
t.Fatal("expecting cycle error, got no error")
}
if diff := cmp.Diff(cyclicProgramErrorMessage, err.Error()); diff != "" {
t.Fatalf("unexpected error message (-want, +got):\n%s", diff)
}
{
name: "Package that imports itself",
program: mapStringLoader{
"main": "package main\nimport _ \"cycle/foo\"\nfunc main() {}",
"cycle/foo": "package foo\nimport _ \"cycle/foo\"",
},
path: "cycle/foo",
pos: ast.Position{Line: 2, Column: 8, Start: 19, End: 31},
msg: `package main
imports cycle/foo
imports cycle/foo: import cycle not allowed`,
},
}

var cyclicTemplate = mapStringReader{
"/index.html": `{% extends "/layout.html" %}`,
"/layout.html": `{% import "/macros/macro.html" %}`,
"/partials/partial.html": `{% import "/macros/macro.html" %}`,
"/macros/macro.html": `{% macro A() %}\n\t{% show "/partials/partial.html" %}\n{% end %}`,
func TestCyclicPrograms(t *testing.T) {
for _, test := range cycleProgramTests {
t.Run(test.name, func(t *testing.T) {
_, err := ParseProgram(test.program)
if err == nil {
t.Fatal("expecting cycle error, got no error")
}
e, ok := err.(*CycleError)
if !ok {
t.Fatalf("expecting *CycleError value, got %T value", err)
}
if diff := cmp.Diff(test.msg, e.Error()); diff != "" {
t.Fatalf("unexpected error message (-want, +got):\n%s", diff)
}
if e.path != test.path {
t.Fatalf(`expecting path %q, got %q`, test.path, e.path)
}
if e.pos != test.pos {
t.Fatalf(`expecting %#v, got %#v`, test.pos, e.pos)
}
})
}
}

const cyclicTemplateErrorMessage = `file /index.html
extends /layout.html
imports /macros/macro.html
shows /partials/partial.html
imports /macros/macro.html: cycle not allowed`
var cycleTemplateTests = []struct {
name string
template mapStringReader
path string
pos ast.Position
msg string
}{

func TestCyclicTemplate(t *testing.T) {
_, err := ParseTemplate("index.html", cyclicTemplate, ast.LanguageHTML, false, nil)
if err == nil {
t.Fatal("expecting cycle error, got no error")
}
if diff := cmp.Diff(cyclicTemplateErrorMessage, err.Error()); diff != "" {
t.Fatalf("unexpected error message (-want, +got):\n%s", diff)
{
name: "Template cycle",
template: mapStringReader{
"/index.html": `{% extends "/layout.html" %}`,
"/layout.html": `{% import "/macros/macro.html" %}`,
"/partials/partial.html": `{% import "/macros/macro.html" %}`,
"/macros/macro.html": `{% macro A() %}\n\t{% show "/partials/partial.html" %}\n{% end %}`,
},
path: "/macros/macro.html",
pos: ast.Position{Line: 1, Column: 23, Start: 22, End: 50},
msg: `file /index.html
extends /layout.html
imports /macros/macro.html
shows /partials/partial.html
imports /macros/macro.html: cycle not allowed`,
},

{
name: "Template cycle on index file",
template: mapStringReader{
"/index.html": `{% extends "/layout.html" %}`,
"/layout.html": `{% import "/macros/macro.html" %}`,
"/macros/macro.html": `{% macro A() %}\n\t{% show "/index.html" %}\n{% end %}`,
},
path: "/index.html",
pos: ast.Position{Line: 1, Column: 4, Start: 3, End: 24},
msg: `file /index.html
extends /layout.html
imports /macros/macro.html
shows /index.html: cycle not allowed`,
},

{
name: "Template cycle on last showd file",
template: mapStringReader{
"/index.html": `{% extends "/layout.html" %}`,
"/layout.html": `{% import "/macros/macro.html" %}`,
"/macros/macro.html": `{% macro A() %}\n\t{% show "/macros/macro.html" %}\n{% end %}`,
},
path: "/macros/macro.html",
pos: ast.Position{Line: 1, Column: 23, Start: 22, End: 46},
msg: `file /index.html
extends /layout.html
imports /macros/macro.html
shows /macros/macro.html: cycle not allowed`,
},

{
name: "Template file that extends itself",
template: mapStringReader{
"/index.html": `{% extends "/index.html" %}`,
},
path: "/index.html",
pos: ast.Position{Line: 1, Column: 4, Start: 3, End: 23},
msg: `file /index.html
extends /index.html: cycle not allowed`,
},

{
name: "Template file that imports itself",
template: mapStringReader{
"/index.html": `{% import "/index.html" %}`,
},
path: "/index.html",
pos: ast.Position{Line: 1, Column: 11, Start: 10, End: 22},
msg: `file /index.html
imports /index.html: cycle not allowed`,
},

{
name: "Template file that shows itself",
template: mapStringReader{
"/index.html": `{% show "/index.html" %}`,
},
path: "/index.html",
pos: ast.Position{Line: 1, Column: 4, Start: 3, End: 20},
msg: `file /index.html
shows /index.html: cycle not allowed`,
},
}

func TestCyclicTemplates(t *testing.T) {
for _, test := range cycleTemplateTests {
t.Run(test.name, func(t *testing.T) {
_, err := ParseTemplate("index.html", test.template, ast.LanguageHTML, false, nil)
if err == nil {
t.Fatal("expecting cycle error, got no error")
}
e, ok := err.(*CycleError)
if !ok {
t.Fatalf("expecting *CycleError value, got %T value", err)
}
if diff := cmp.Diff(test.msg, e.Error()); diff != "" {
t.Fatalf("unexpected error message (-want, +got):\n%s", diff)
}
if e.path != test.path {
t.Fatalf(`expecting path %q, got %q`, test.path, e.path)
}
if e.pos != test.pos {
t.Fatalf(`expecting %#v, got %#v`, test.pos, e.pos)
}
})
}
}

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14 changes: 9 additions & 5 deletions compiler/parser_program.go
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Original file line number Diff line number Diff line change
Expand Up @@ -81,15 +81,19 @@ func ParseProgram(packages PackageLoader) (*ast.Tree, error) {
for i, p := range imports {
if p.Path == imp.Path {
// There is a cycle.
err := "package "
err := &CycleError{
path: p.Path,
pos: *(imp.Pos()),
}
err.msg = "package "
for i, imp = range imports {
if i > 0 {
err += "\n\timports "
err.msg += "\n\timports "
}
err += imp.Path
err.msg += imp.Path
}
err += "\n\timports " + p.Path + ": import cycle not allowed"
return nil, cycleError(err)
err.msg += "\n\timports " + p.Path + ": import cycle not allowed"
return nil, err
}
}
imp.Tree = tree
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29 changes: 19 additions & 10 deletions compiler/parser_template.go
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Original file line number Diff line number Diff line change
Expand Up @@ -54,8 +54,8 @@ func ParseTemplate(path string, reader FileReader, lang ast.Language, relaxedBoo
if err != nil {
if err2, ok := err.(*SyntaxError); ok && err2.path == "" {
err2.path = path
} else if err2, ok := err.(cycleError); ok {
err = cycleError("file " + path + string(err2) + ": cycle not allowed")
} else if e, ok := err.(*CycleError); ok {
e.msg = "file " + path + e.msg + ": cycle not allowed"
} else if os.IsNotExist(err) {
err = ErrNotExist
}
Expand Down Expand Up @@ -94,7 +94,7 @@ func (pp *templateExpansion) parseFile(name string, lang ast.Language) (*ast.Tre
// Check if there is a cycle.
for _, p := range pp.paths {
if p == name {
return nil, cycleError("")
return nil, &CycleError{path: p}
}
}

Expand All @@ -121,13 +121,13 @@ func (pp *templateExpansion) parseFile(name string, lang ast.Language) (*ast.Tre
// Expand the nodes.
pp.paths = append(pp.paths, name)
err = pp.expand(tree.Nodes)
pp.paths = pp.paths[:len(pp.paths)-1]
if err != nil {
if e, ok := err.(*SyntaxError); ok && e.path == "" {
e.path = name
}
return nil, err
}
pp.paths = pp.paths[:len(pp.paths)-1]

// Add the tree to the cache.
pp.trees.Add(name, lang, tree)
Expand Down Expand Up @@ -228,8 +228,11 @@ func (pp *templateExpansion) expand(nodes []ast.Node) error {
err = fmt.Errorf("invalid path %q at %s", n.Path, n.Pos())
} else if os.IsNotExist(err) {
err = syntaxError(n.Pos(), "extends path %q does not exist", absPath)
} else if err2, ok := err.(cycleError); ok {
err = cycleError("\n\textends " + absPath + string(err2))
} else if e, ok := err.(*CycleError); ok {
e.msg = "\n\textends " + absPath + e.msg
if e.path == pp.paths[len(pp.paths)-1] {
e.pos = *(n.Pos())
}
}
return err
}
Expand Down Expand Up @@ -264,8 +267,11 @@ func (pp *templateExpansion) expand(nodes []ast.Node) error {
err = fmt.Errorf("invalid path %q at %s", n.Path, n.Pos())
} else if os.IsNotExist(err) {
err = syntaxError(n.Pos(), "import path %q does not exist", absPath)
} else if err2, ok := err.(cycleError); ok {
err = cycleError("\n\timports " + absPath + string(err2))
} else if e, ok := err.(*CycleError); ok {
e.msg = "\n\timports " + absPath + e.msg
if e.path == pp.paths[len(pp.paths)-1] {
e.pos = *(n.Pos())
}
}
return err
}
Expand All @@ -283,8 +289,11 @@ func (pp *templateExpansion) expand(nodes []ast.Node) error {
err = fmt.Errorf("invalid path %q at %s", n.Path, n.Pos())
} else if os.IsNotExist(err) {
err = syntaxError(n.Pos(), "shown path %q does not exist", absPath)
} else if err2, ok := err.(cycleError); ok {
err = cycleError("\n\tshows " + absPath + string(err2))
} else if e, ok := err.(*CycleError); ok {
e.msg = "\n\tshows " + absPath + e.msg
if e.path == pp.paths[len(pp.paths)-1] {
e.pos = *(n.Pos())
}
}
return err
}
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