don't pass GIT_TRACE to exec.Command calls in the git package

git/git.go

@@ -3,6 +3,7 @@ package git
 
 import (
 	"bufio"
+	"bytes"
 	"errors"
 	"fmt"
 	"io/ioutil"
@@ -455,10 +456,13 @@ func GetCommitSummary(commit string) (*CommitSummary, error) {
 
 func GitAndRootDirs() (string, string, error) {
 	cmd := execCommand("git", "rev-parse", "--git-dir", "--show-toplevel")
-	out, err := cmd.CombinedOutput()
+	buf := &bytes.Buffer{}
+	cmd.Stderr = buf
+
+	out, err := cmd.Output()
 	output := string(out)
 	if err != nil {
-		return "", "", fmt.Errorf("Failed to call git rev-parse --git-dir --show-toplevel: %q", output)
+		return "", "", fmt.Errorf("Failed to call git rev-parse --git-dir --show-toplevel: %q", buf.String())
 	}
 
 	paths := strings.Split(output, "\n")
@@ -617,3 +621,22 @@ func IsVersionAtLeast(actualVersion, desiredVersion string) bool {
 
 	return actual >= atleast
 }
+
+// An env for an exec.Command without GIT_TRACE
+var env []string
+var traceEnv = "GIT_TRACE="
+
+func init() {
+	realEnv := os.Environ()
+	env = make([]string, 0, len(realEnv))
+
+	for _, kv := range realEnv {
+		if strings.HasPrefix(kv, traceEnv) {
+			continue
+		}
+		env = append(env, kv)
+	}
+
+	fmt.Println(env)
+	fmt.Println(realEnv)
+}

git/git_nix.go

@@ -9,5 +9,7 @@ import (
 
 // execCommand is a small platform specific wrapper around os/exec.Command
 func execCommand(name string, arg ...string) *exec.Cmd {
-	return exec.Command(name, arg...)
+	cmd := exec.Command(name, arg...)
+	cmd.Env = env
+	return cmd
 }

git/git_test.go

@@ -260,7 +260,6 @@ func TestWorkTrees(t *testing.T) {
 }
 
 func TestVersionCompare(t *testing.T) {
-
 	assert.Equal(t, true, IsVersionAtLeast("2.6.0", "2.6.0"))
 	assert.Equal(t, true, IsVersionAtLeast("2.6.0", "2.6"))
 	assert.Equal(t, true, IsVersionAtLeast("2.6.0", "2"))
@@ -272,3 +271,12 @@ func TestVersionCompare(t *testing.T) {
 	assert.Equal(t, false, IsVersionAtLeast("2.5.0", "2.5.1"))
 	assert.Equal(t, false, IsVersionAtLeast("2.5.2", "2.5.10"))
 }
+
+func TestGitAndRootDirs(t *testing.T) {
+	git, root, err := GitAndRootDirs()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	assert.Equal(t, git, root+"/.git")
+}

git/git_win.go

@@ -12,5 +12,6 @@ import (
 func execCommand(name string, arg ...string) *exec.Cmd {
 	cmd := exec.Command(name, arg...)
 	cmd.SysProcAttr = &syscall.SysProcAttr{HideWindow: true}
+	cmd.Env = env
 	return cmd
 }

script/cibuild

@@ -1,4 +1,8 @@
 #!/usr/bin/env bash
 set -e
 script/test
+
+# re-run test to ensure GIT_TRACE output doesn't leak into the git package
+GIT_TRACE=1 script/test git
+
 VERBOSE_LOGS=1 script/integration