write soong.environment.used.* file only if changed
Bug: b/255309129
Test: `lunch aosp_x86-userdebug` and `export NINJA_ARGS="-d explain"`
Then do the following:
1) rm -rf out && m bp2build
2) touch bionic/libc && m bp2build
3) ALLOW_MISSING_DEPENDENCIES=true m bp2build
After each step above observe the following two
a)`stat out/soong/soong.environment.used.bp2build | grep Modify`
b)`stat out/soong/bp2build_workspace_marker | grep Modify`
Verified:
step 2 changes only (b) - prior to this CL, it'd change (a) as well
step 3 still changes both (as expected)
Change-Id: I98a94878a14e19043f448b0904fc67d5d1dc9733
diff --git a/cmd/soong_build/main.go b/cmd/soong_build/main.go
index 70f58f5..c1a66db 100644
--- a/cmd/soong_build/main.go
+++ b/cmd/soong_build/main.go
@@ -15,6 +15,7 @@
package main
import (
+ "bytes"
"flag"
"fmt"
"io/ioutil"
@@ -478,12 +479,19 @@
os.Exit(1)
}
- err = ioutil.WriteFile(path, data, 0666)
- if err != nil {
+ if preexistingData, err := os.ReadFile(path); err != nil {
+ if !os.IsNotExist(err) {
+ fmt.Fprintf(os.Stderr, "error reading used environment file '%s': %s\n", usedEnvFile, err)
+ os.Exit(1)
+ }
+ } else if bytes.Equal(preexistingData, data) {
+ // used environment file is unchanged
+ return
+ }
+ if err = os.WriteFile(path, data, 0666); err != nil {
fmt.Fprintf(os.Stderr, "error writing used environment file '%s': %s\n", usedEnvFile, err)
os.Exit(1)
}
-
// Touch the output file so that it's not older than the file we just
// wrote. We can't write the environment file earlier because one an access
// new environment variables while writing it.