parser: avoid expensive heredocs evaluations early

tonistiigi · tonistiigi · commit bcc3c9834fea · 2024-06-21T08:05:55.000-07:00
Atm every line needs to be fully evaluated while it is
unlikely that a random line happens to be a heredoc.

Signed-off-by: Tonis Tiigi &lt;tonistiigi@gmail.com&gt;
diff --git a/frontend/dockerfile/parser/parser.go b/frontend/dockerfile/parser/parser.go
@@ -347,7 +347,7 @@ func Parse(rwc io.Reader) (*Result, error) {
 			return nil, withLocation(err, startLine, currentLine)
 		}
 
-		if child.canContainHeredoc() {
+		if child.canContainHeredoc() && strings.Contains(line, "<<") {
 			heredocs, err := heredocsFromLine(line)
 			if err != nil {
 				return nil, withLocation(err, startLine, currentLine)

Original file line number	Diff line number	Diff line change
`@@ -347,7 +347,7 @@ func Parse(rwc io.Reader) (*Result, error) {`
`347`	`347`	`return nil, withLocation(err, startLine, currentLine)`
`348`	`348`	`}`
`349`	`349`
`350`		`- if child.canContainHeredoc() {`
	`350`	`+ if child.canContainHeredoc() && strings.Contains(line, "<<") {`
`351`	`351`	`heredocs, err := heredocsFromLine(line)`
`352`	`352`	`if err != nil {`
`353`	`353`	`return nil, withLocation(err, startLine, currentLine)`