railpack

1package build_llb2 3import (4	"maps"5	"slices"6)7 8type BuildEnvironment struct {9	PathList []string10	EnvVars  map[string]string11}12 13func NewGraphEnvironment() BuildEnvironment {14	return BuildEnvironment{15		PathList: make([]string, 0),16		EnvVars:  make(map[string]string),17	}18}19 20// Merges the other environment into the current environment21func (e *BuildEnvironment) Merge(other BuildEnvironment) {22	e.PathList = appendUniquePaths(e.PathList, other.PathList...)23	maps.Copy(e.EnvVars, other.EnvVars)24}25 26func appendUniquePaths(existing []string, additions ...string) []string {27	// Steps with shared ancestors inherit the same paths, so merging their outputs can28	// otherwise duplicate entries in downstream steps and the final image PATH. Keep29	// the first occurrence to preserve path precedence.30	for _, path := range additions {31		if slices.Contains(existing, path) {32			continue33		}34		existing = append(existing, path)35	}36	return existing37}38 39func (e *BuildEnvironment) PushPath(path string) {40	if slices.Contains(e.PathList, path) {41		return42	}43	e.PathList = append([]string{path}, e.PathList...)44}45 46func (e *BuildEnvironment) AddEnvVar(key, value string) {47	e.EnvVars[key] = value48}49