Refactoring/#18-use-lua-cjson (#27)

* Migrate to lua-cjson

.github/workflows/build.yml

@@ -99,12 +99,6 @@ jobs:
             EXASOL_USER=sys EXASOL_PASSWORD=exasol \
             busted --run=ci_repeated
 
-      - name: Archive repeated tests results
-        if: ${{ always() }}
-        uses: actions/upload-artifact@v2
-        with:
-          name: repeated-test-reports
-          path: target/luaunit-reports/*
 
 ## Deactivated until requirements and coverage are added
 

doc/changes/changes_0.1.0.md

@@ -15,6 +15,7 @@ Code name: Initial Release
 ## Refactoring
 
 * #25: Migrated tests to busted
+* #18: Replaced lunajson with cjson
 
 ## Documentation
 

doc/developer_guide/developer_guide.md

@@ -22,7 +22,7 @@ Install the prerequisites like this:
     sudo yum install lua lua-devel luarocks openssl-devel lua-luaossl plantuml
     ```
 
-### Install Runtime and Test Dependencies
+### Install Runtime Dependencies
 
 See the [list of dependencies](../../dependencies.md) for details. Install dependencies by executing:
 
@@ -37,6 +37,27 @@ openssl=/usr/local/Cellar/[email protected]/1.1.1m/
 luarocks install --local --deps-only *.rockspec OPENSSL_DIR=$openssl CRYPTO_DIR=$openssl
 ```
 
+### Install Test and Build Dependencies
+
+```sh
+luarocks install --local busted
+```
+
+#### Troubleshooting `lua-cjson` installation
+
+`lua-cjson` is pinned to version `2.1.0` because later versions fail installation with error `undefined symbol: lua_objlen` or `implicit declaration of function 'lua_objlen' is invalid in C99`:
+
+```
+lua_cjson.c:743:19: error: implicit declaration of function 'lua_objlen' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
+            len = lua_objlen(l, -1);
+```
+
+To use the latest version you can optionally install it with additional build flags:
+
+```sh
+luarocks install lua-cjson --local "CFLAGS=-O3 -Wall -pedantic -DNDEBUG -DLUA_COMPAT_5_3"
+```
+
 ## Running Tests
 
 You need an Exasol database for running the tests. You can start a Docker instance either manually as described in [docker-db](https://github.com/EXASOL/docker-db) or using the [integration-test-docker-environment](https://github.com/exasol/integration-test-docker-environment).

exasol-driver-lua-0.1.0-1.rockspec

@@ -28,7 +28,7 @@ dependencies = {
     "luasocket >= 3.0rc1-2",
     "luasec >= 1.0.2-1",
     "luaossl >= 20200709-0",
-    "lunajson >= 1.2.3-1",
+    "lua-cjson == 2.1.0", -- pinned to prevent "undefined symbol: lua_objlen" in 2.1.0.6
     "base64 >= 1.5-3",
     "exaerror >= 1.2.2-1",
     "remotelog >= 1.1.1-1"

src/exasol_websocket.lua

@@ -1,6 +1,6 @@
 local M = {}
 
-local lunajson = require("lunajson")
+local cjson = require("cjson")
 local exaerror = require("exaerror")
 -- [impl->dsn~logging-with-remotelog~1]
 local log = require("remotelog")
@@ -54,7 +54,7 @@ local function get_response_error(response)
 end
 
 function M:_send_json(payload, ignore_response)
-    local raw_payload = lunajson.encode(payload)
+    local raw_payload = cjson.encode(payload)
     log.trace("Sending payload '%s'", raw_payload)
     local raw_response, err = self.websocket:send_raw(raw_payload, ignore_response)
     if ignore_response then return nil, nil end
@@ -67,7 +67,7 @@ function M:_send_json(payload, ignore_response)
     end
 
     log.trace("Received response of %d bytes", #raw_response)
-    local response = lunajson.decode(raw_response)
+    local response = cjson.decode(raw_response)
     err = get_response_error(response)
     if err then
         return nil, err