refactor: share UpdateFromEnv logic (#1457)

* refactor: share UpdateFromEnv logic

* Add test for GITHUB_OUTPUT

Co-authored-by: Ben Randall <veleek@gmail.com>

* Add GITHUB_STATE test

* Add test for the old broken parser

Co-authored-by: Ben Randall <veleek@gmail.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

pkg/container/parse_env_file.go

@@ -0,0 +1,60 @@
+package container
+
+import (
+	"archive/tar"
+	"bufio"
+	"context"
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/nektos/act/pkg/common"
+)
+
+func parseEnvFile(e Container, srcPath string, env *map[string]string) common.Executor {
+	localEnv := *env
+	return func(ctx context.Context) error {
+		envTar, err := e.GetContainerArchive(ctx, srcPath)
+		if err != nil {
+			return nil
+		}
+		defer envTar.Close()
+		reader := tar.NewReader(envTar)
+		_, err = reader.Next()
+		if err != nil && err != io.EOF {
+			return err
+		}
+		s := bufio.NewScanner(reader)
+		for s.Scan() {
+			line := s.Text()
+			singleLineEnv := strings.Index(line, "=")
+			multiLineEnv := strings.Index(line, "<<")
+			if singleLineEnv != -1 && (multiLineEnv == -1 || singleLineEnv < multiLineEnv) {
+				localEnv[line[:singleLineEnv]] = line[singleLineEnv+1:]
+			} else if multiLineEnv != -1 {
+				multiLineEnvContent := ""
+				multiLineEnvDelimiter := line[multiLineEnv+2:]
+				delimiterFound := false
+				for s.Scan() {
+					content := s.Text()
+					if content == multiLineEnvDelimiter {
+						delimiterFound = true
+						break
+					}
+					if multiLineEnvContent != "" {
+						multiLineEnvContent += "\n"
+					}
+					multiLineEnvContent += content
+				}
+				if !delimiterFound {
+					return fmt.Errorf("invalid format delimiter '%v' not found before end of file", multiLineEnvDelimiter)
+				}
+				localEnv[line[:multiLineEnv]] = multiLineEnvContent
+			} else {
+				return fmt.Errorf("invalid format '%v', expected a line with '=' or '<<'", line)
+			}
+		}
+		env = &localEnv
+		return nil
+	}
+}