Recreate prepared statements if invalidated (#195)

fixes #120

...

lib/connection.js

@@ -3,7 +3,7 @@ const tls = require('tls')
 const frontend = require('./frontend.js')
 const Backend = require('./backend.js')
 const Queue = require('./queue.js')
-const { END } = require('./types.js')
+const { END, retryRoutines } = require('./types.js')
 const { errors } = require('./errors.js')
 
 module.exports = Connection
@@ -128,8 +128,17 @@ function Connection(options = {}) {
       q.reject(err)
   }
 
+  function retry(query) {
+    query.retried = true
+    delete statements[query.sig]
+    ready = true
+    backend.query = backend.error = null
+    send(query, { sig: query.sig, str: query.str, args: query.args })
+  }
+
   function send(query, { sig, str, args = [] }) {
     try {
+      query.sig = sig
       query.str = str
       query.args = args
       query.result = []
@@ -204,6 +213,9 @@ function Connection(options = {}) {
     clearTimeout(connect_timer)
     if (err) {
       if (backend.query) {
+        if (!backend.query.retried && retryRoutines[err.routine])
+          return retry(backend.query)
+
         err.stack += backend.query.origin.replace(/.*\n/, '\n')
         Object.defineProperty(err, 'query', {
           value: backend.query.str,

lib/types.js

@@ -192,3 +192,9 @@ module.exports.errorFields = entries({
   L: 'line',
   R: 'routine'
 }).reduce(char, {})
+
+module.exports.retryRoutines = {
+  FetchPreparedStatement: true,
+  RevalidateCachedQuery: true,
+  transformAssignedExpr: true
+}

tests/index.js

@@ -1421,6 +1421,7 @@ t('Copy from works in transaction', async() => {
 })
 
 t('Copy from abort works', async() => {
+  const sql = postgres(options)
   const controller = new AbortController()
   const readable = fs.createReadStream('copy.csv')
 
@@ -1438,5 +1439,32 @@ t('Copy from abort works', async() => {
   controller.abort()
   await sql.end()
 
-  return [aborted, true]
+  return [
+    aborted,
+    true,
+    await postgres(options)`drop table test`
+  ]
+})
+
+t('Recreate prepared statements on transformAssignedExpr error', async() => {
+  const insert = () => sql`insert into test (name) values (${ '1' }) returning name`
+  await sql`create table test (name text)`
+  await insert()
+  await sql`alter table test alter column name type int using name::integer`
+  return [
+    1, (await insert())[0].name,
+    await sql`drop table test`
+  ]
+})
+
+t('Recreate prepared statements on RevalidateCachedQuery error', async() => {
+  const select = () => sql`select name from test`
+  await sql`create table test (name text)`
+  await sql`insert into test values ('1')`
+  await select()
+  await sql`alter table test alter column name type int using name::integer`
+  return [
+    1, (await select())[0].name,
+    await sql`drop table test`
+  ]
 })