Backport new ExportVariable and SetPath

Backport implementation from actions/toolkit#571

Author: tjamet

core/command.go

@@ -45,6 +45,21 @@ func IssueCommand(kind string, properties map[string]string, message string) {
 	stdoutSetter.Unlock()
 }
 
+// issueFileCommand implements stores the command in a file
+// see https://github.com/actions/toolkit/pull/571/files#diff-9ce6eb99f5fb5529e795254801e03ae56d67d3d5fcbec635f91e9a8a61ad8b64R10
+func issueFileCommand(command string, message string) error {
+	path, ok := os.LookupEnv("GITHUB_" + command)
+	if ok {
+		fd, err := os.OpenFile(path, os.O_RDWR, 0)
+		if err != nil {
+			return err
+		}
+		fmt.Fprintln(fd, message)
+		return nil
+	}
+	return fmt.Errorf("unable to find command file GITHUB_%s", command)
+}
+
 type command struct {
 	command    string
 	properties map[string]string

core/core.go

@@ -22,8 +22,11 @@ var (
 
 // ExportVariable sets the environment varaible name (for this action and future actions)
 func ExportVariable(name, value string) {
+	const delimiter = "_GitHubActionsFileCommandDelimeter_"
+	if err := issueFileCommand("ENV", fmt.Sprintf("%s<<%s%s%s%s%s", name, delimiter, EOF, value, delimiter, EOF)); err != nil {
+		IssueCommand("set-env", map[string]string{"name": name}, value)
+	}
 	os.Setenv(name, value)
-	IssueCommand("set-env", map[string]string{"name": name}, value)
 }
 
 // SetSecret registers a secret which will get masked from logs
@@ -33,8 +36,10 @@ func SetSecret(secret string) {
 
 // AddPath prepends inputPath to the PATH (for this action and future actions)
 func AddPath(path string) {
+	if err := issueFileCommand("PATH", path); err != nil {
+		Issue("add-path", path)
+	}
 	// TODO js: process.env['PATH'] = `${inputPath}${path.delimiter}${process.env['PATH']}`
-	Issue("add-path", path)
 }
 
 // GetBoolInput gets the value of an input and returns whether it equals "true".

core/core_unix.go

@@ -0,0 +1,3 @@
+package core
+
+const EOF = "\n"

core/core_windows.go

@@ -0,0 +1,3 @@
+package core
+
+const EOF = "\r\n"