Ensure transactions throw if connection is closed while there is no a…

…ctive query - fixes #658

src/connection.js

@@ -441,7 +441,7 @@ function Connection(options, queues = {}, { onopen = noop, onend = noop, onclose
     closedDate = performance.now()
     hadError && options.shared.retries++
     delay = (typeof backoff === 'function' ? backoff(options.shared.retries) : backoff) * 1000
-    onclose(connection)
+    onclose(connection, Errors.connection('CONNECTION_CLOSED', options, socket))
   }
 
   /* Handlers */

src/index.js

@@ -239,7 +239,10 @@ function Postgres(a, b) {
 
     try {
       await sql.unsafe('begin ' + options.replace(/[^a-z ]/ig, ''), [], { onexecute }).execute()
-      return await scope(connection, fn)
+      return await Promise.race([
+        scope(connection, fn),
+        new Promise((_, reject) => connection.onclose = reject)
+      ])
     } catch (error) {
       throw error
     }
@@ -414,9 +417,10 @@ function Postgres(a, b) {
       : move(c, full)
   }
 
-  function onclose(c) {
+  function onclose(c, e) {
     move(c, closed)
     c.reserved = null
+    c.onclose && (c.onclose(e), c.onclose = null)
     options.onclose && options.onclose(c.id)
     queries.length && connect(c, queries.shift())
   }

tests/index.js

@@ -2348,6 +2348,16 @@ t('Ensure reconnect after max_lifetime with transactions', { timeout: 5 }, async
   return [true, true]
 })
 
+
+t('Ensure transactions throw if connection is closed dwhile there is no query', async() => {
+  const x = await sql.begin(async() => {
+    setTimeout(() => sql.end({ timeout: 0 }), 10)
+    await new Promise(r => setTimeout(r, 200))
+    return sql`select 1`
+  }).catch(x => x)
+  return ['CONNECTION_CLOSED', x.code]
+})
+
 t('Custom socket', {}, async() => {
   let result
   const sql = postgres({