Add QuickJS as a Javascript engine option #5049
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https://bellard.org/quickjs Some benefits over SM: * Small. We're using 6 or so C files vs 700+ SM91 C++ files. * Built with Apache CouchDB as opposed having to maintain a separate SM package, like for RHEL9, for instance, where they dropped support for SM already. (see #4154). * Embedding friendly. Designed from ground-up for embedding. SM has been updating the C++ API such that we have to keep copy-pasting new versions of our C++ code every year or so. (see #4305). * Easy to modify to accept Spidermonkey 1.8.5 top level functions for map/reduce code so we don't have have to parse the JS, AST transform it, and then re-compile it. * Configurable runtime feature set - can disable workers, promises and other API and features which may not work well in a backend JS environment. Some users may want more, some may want to disable even Date(time) features to hedge again Spectre-style attacks (spectreattack.com). * Allows granular time (reduction) tracking if we wanted to provide a runtime allowance for each function. * Better sandboxing. Creating a whole JSRuntime takes only 300 microseconds, so we can afford to do that on reset. JSRuntimes cannot share JS data or object between them. * Seems to be faster in preliminary benchmarking with small concurrent VDU and view builds: https://gist.github.com/nickva/ed239651114794ebb138b1f16c5f6758 Results seem promising: - 4x faster than SM 1.8.5 - 5x faster than SM 91 - 6x reduced memory usage per couchjs process (5MB vs 30MB) * Allows compiling JS bytecode ahead of time a C array of bytes. QuickJS can be built alongside Spidermonkey and toggled on/off at runtime: ``` ./configure --dev --js-engine=quickjs ``` This makes it the default engine. But Spidermonkey can still be set in the config option. ``` [couchdb] js_engine = spidermonkey | quickjs ``` To test individual views, without switching the default use the `javascript_quickjs` language in the design docs. To keep using Spidermonkey engine after switching the default, can use `javascript_spidermonkey` language in design docs. However, language selection will reset the view and the view will have to be rebuilt. It's also possible to build without Spidermonkey support completely by using: ``` ./configure --disable-spidermonkey ``` Issue: #4448
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This is a test PR to run the full CI to check quickjs on other arches/os versions