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Rewrite contexts before evaluating them (#287)

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* Rewrite contexts before evaluating them

* Precompile context and expression patterns

* Test trim before rewrite

The current contextPattern is quite constraining and would fail the
rewrite of a context with trailing spaces. Triming happens during the
execution of Interpolate, and these tests aim to detect future breaking
changes on this behavior.

Co-authored-by: Casey Lee <cplee@nektos.com>
This commit is contained in:
Ayaz BADOURALY
2020-06-24 16:08:45 +02:00
committed by GitHub
parent 64b8d2afa4
commit 7dcd0bc1bb
2 changed files with 101 additions and 14 deletions
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45
pkg/runner/expression.go
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@@ -17,13 +17,11 @@ import (
"gopkg.in/godo.v2/glob"
)
const prefix = "${{"
const suffix = "}}"
var pattern *regexp.Regexp
var contextPattern, expressionPattern *regexp.Regexp
func init() {
pattern = regexp.MustCompile(fmt.Sprintf("\\%s.+?%s", prefix, suffix))
contextPattern = regexp.MustCompile(`^(\w+(?:\[.+\])*)(?:\.([\w-]+))?(.*)$`)
expressionPattern = regexp.MustCompile(`\${{\s*(.+?)\s*}}`)
}
// NewExpressionEvaluator creates a new evaluator
@@ -54,6 +52,7 @@ func (sc *StepContext) NewExpressionEvaluator() ExpressionEvaluator {
type ExpressionEvaluator interface {
Evaluate(string) (string, error)
Interpolate(string) string
Rewrite(string) string
}
type expressionEvaluator struct {
@@ -61,7 +60,12 @@ type expressionEvaluator struct {
}
func (ee *expressionEvaluator) Evaluate(in string) (string, error) {
val, err := ee.vm.Run(in)
re := ee.Rewrite(in)
if re != in {
logrus.Debugf("Evaluating '%s' instead of '%s'", re, in)
}
val, err := ee.vm.Run(re)
if err != nil {
return "", err
}
@@ -76,8 +80,10 @@ func (ee *expressionEvaluator) Interpolate(in string) string {
out := in
for {
out = pattern.ReplaceAllStringFunc(in, func(match string) string {
expression := strings.TrimPrefix(strings.TrimSuffix(match, suffix), prefix)
out = expressionPattern.ReplaceAllStringFunc(in, func(match string) string {
// Extract and trim the actual expression inside ${{...}} delimiters
expression := expressionPattern.ReplaceAllString(match, "$1")
// Evaluate the expression and retrieve errors if any
evaluated, err := ee.Evaluate(expression)
if err != nil {
errList = append(errList, err)
@@ -89,7 +95,7 @@ func (ee *expressionEvaluator) Interpolate(in string) string {
break
}
if out == in {
// no replacement occurred, we're done!
// No replacement occurred, we're done!
break
}
in = out
@@ -97,6 +103,27 @@ func (ee *expressionEvaluator) Interpolate(in string) string {
return out
}
// Rewrite tries to transform any javascript property accessor into its bracket notation.
// For instance, "object.property" would become "object['property']".
func (ee *expressionEvaluator) Rewrite(in string) string {
re := in
for {
matches := contextPattern.FindStringSubmatch(re)
if matches == nil {
// No global match, we're done!
break
}
if matches[2] == "" {
// No property match, we're done!
break
}
re = fmt.Sprintf("%s['%s']%s", matches[1], matches[2], matches[3])
}
return re
}
func (rc *RunContext) newVM() *otto.Otto {
configers := []func(*otto.Otto){
vmContains,