Freeze environment reading after saving deps

Any reads after the deps are saved won't show up as dependencies later.
So panic if new environment variables are read after saving deps.

Change-Id: Ia51deaf750804d3b99e69c001939a104c2d8c9f2

1 files changed, 9 insertions, 2 deletions

diff --git a/common/config.go b/common/config.go
index 348d0dbb..f8231f07 100644
--- a/common/config.go
+++ b/common/config.go
@@ -48,8 +48,9 @@ type config struct {
 
 	srcDir string // the path of the root source directory
 
-	envLock sync.Mutex
-	envDeps map[string]string
+	envLock   sync.Mutex
+	envDeps   map[string]string
+	envFrozen bool
 }
 
 type jsonConfigurable interface {
@@ -178,6 +179,9 @@ func (c *config) Getenv(key string) string {
 	var exists bool
 	c.envLock.Lock()
 	if val, exists = c.envDeps[key]; !exists {
+		if c.envFrozen {
+			panic("Cannot access new environment variables after envdeps are frozen")
+		}
 		val = os.Getenv(key)
 		c.envDeps[key] = val
 	}
@@ -186,6 +190,9 @@ func (c *config) Getenv(key string) string {
 }
 
 func (c *config) EnvDeps() map[string]string {
+	c.envLock.Lock()
+	c.envFrozen = true
+	c.envLock.Unlock()
 	return c.envDeps
 }