fix(env): stop filtering process.env (#23)

We should not be removing GIT_ values from the environment if the user
has set them.  All we now do is set two defaults if they were not
already set by the end user.

lib/opts.js

@@ -1,6 +1,11 @@
-const gitEnv = require('./env.js')
+// Values we want to set if they're not already defined by the end user
+// This defaults to accepting new ssh host key fingerprints
+const gitEnv = {
+  GIT_ASKPASS: 'echo',
+  GIT_SSH_COMMAND: 'ssh -oStrictHostKeyChecking=accept-new'
+}
 module.exports = (opts = {}) => ({
   stdioString: true,
   ...opts,
-  env: opts.env || gitEnv(),
+  env: opts.env || { ...gitEnv, ...process.env }
 })

package.json

@@ -35,7 +35,6 @@
     "promise-inflight": "^1.0.1",
     "promise-retry": "^2.0.1",
     "semver": "^7.3.5",
-    "unique-filename": "^1.1.1",
     "which": "^2.0.2"
   }
 }

test/opts.js

@@ -1,8 +1,26 @@
 const t = require('tap')
 const gitOpts = require('../lib/opts.js')
-const gitEnv = require('../lib/env.js')
+const gitEnv = {
+  GIT_ASKPASS: 'echo',
+  GIT_SSH_COMMAND: 'ssh -oStrictHostKeyChecking=accept-new'
+}
 
-t.match(gitOpts().env, gitEnv(), 'got the git env by default')
+t.match(gitOpts().env, gitEnv, 'got the git defaults we want')
+
+t.test('does not override', t => {
+  const { GIT_ASKPASS, GIT_SSH_COMMAND } = process.env
+  t.teardown(() => {
+    process.env.GIT_ASKPASS = GIT_ASKPASS
+    process.env.GIT_SSH_COMMAND = GIT_SSH_COMMAND
+  })
+  process.env.GIT_ASKPASS = 'test_askpass'
+  process.env.GIT_SSH_COMMAND = 'test_ssh_command'
+  t.match(gitOpts().env, {
+    GIT_ASKPASS: 'test_askpass',
+    GIT_SSH_COMMAND: 'test_ssh_command',
+  }, 'values already in process.env remain')
+  t.end()
+})
 
 t.test('as non-root', t => {
   process.getuid = () => 999