Split python polyglot into a bash script and a js script

Makefile

@@ -25,6 +25,7 @@ all-but-packages: \
 	 \
 	dist/package.json \
 	dist/python \
+	dist/python_cli_entry.js \
 	dist/python_stdlib.zip \
 	dist/test.html \
 	dist/module_test.html \
@@ -252,6 +253,9 @@ dist/module_test.html: src/templates/module_test.html
 dist/python: src/templates/python
 	cp $< $@
 
+dist/python_cli_entry.js: src/templates/python_cli_entry.js
+	cp $< $@
+
 .PHONY: dist/console.html
 dist/console.html: src/templates/console.html
 	cp $< $@

src/js/emscripten-settings.ts

@@ -17,6 +17,7 @@ export interface EmscriptenSettings {
   readonly print?: (a: string) => void;
   readonly printErr?: (a: string) => void;
   readonly onExit?: (code: number) => void;
+  readonly thisProgram?: string;
   readonly arguments: readonly string[];
   readonly instantiateWasm?: (
     imports: { [key: string]: any },
@@ -49,6 +50,7 @@ export function createSettings(config: ConfigType): EmscriptenSettings {
     onExit(code) {
       settings.exitCode = code;
     },
+    thisProgram: config.sysExecutable,
     arguments: config.args,
     API: { config } as API,
     // Emscripten calls locateFile exactly one time with argument

src/js/pyodide.ts

@@ -46,6 +46,7 @@ export type ConfigType = {
   stdout?: (msg: string) => void;
   stderr?: (msg: string) => void;
   jsglobals?: object;
+  sysExecutable?: string;
   args: string[];
   _node_mounts: string[];
   env: { [key: string]: string };
@@ -139,6 +140,10 @@ export async function loadPyodide(
      * Default: ``globalThis``
      */
     jsglobals?: object;
+    /**
+     * Determine the value of ``sys.executable``.
+     */
+    sysExecutable?: string;
     /**
      * Command line arguments to pass to Python on startup. See `Python command
      * line interface options

src/templates/python

@@ -1,28 +1,6 @@
 #!/usr/bin/env bash
-":" /* << "EOF"
-This file is a bash/node polyglot. This is needed for a few reasons:
-
-TODO: We don't support node < 18 anymore, so maybe we can remove this?
-
-1. In node 14 we must pass `--experimental-wasm-bigint`. In node >14 we cannot
-pass --experimental-wasm-bigint
-
-2. Emscripten vendors node 14 so it is desirable not to require node >= 16
-
-3. We could use a bash script in a separate file to determine the flags needed,
-but virtualenv looks up the current file and uses it directly. So if we make
-python.sh and have it invoke python.js, then the virtualenv will invoke python.js
-directly without the `--experimental-wasm-bigint` flag and so the virtualenv won't
-work with node 14.
-
-Keeping the bash script and the JavaScript in the same file makes sure that even
-inside the virtualenv the proper shell code is executed.
-*/
-
-/*
-EOF
-# bash
 set -e
+
 if [[ $1 == "-m" ]] && [[ $2 == "pip" ]]; then
     # redirect python -m pip to execute in host environment
     shift 1
@@ -46,154 +24,23 @@ process.stdout.write("--");
 EOF
 )")
 
-exec node "$ARGS" "$0" "$@"
-*/
-
-
-const { loadPyodide } = require("./pyodide");
-const fs = require("fs");
-
-/**
- * Determine which native top level directories to mount into the Emscripten
- * file system.
- *
- * This is a bit brittle, if the machine has a top level directory with certain
- * names it is possible this could break. The most surprising one here is tmp, I
- * am not sure why but if we link tmp then the process silently fails.
- */
-function rootDirsToMount() {
-    const skipDirs = ["dev", "lib", "proc", "tmp"];
-    return fs
-        .readdirSync("/")
-        .filter((dir) => !skipDirs.includes(dir))
-        .map((dir) => "/" + dir);
-}
-
-function dirsToMount() {
-    extra_mounts = process.env["_PYODIDE_EXTRA_MOUNTS"] || "";
-    return rootDirsToMount().concat(extra_mounts.split(":").filter(s => s))
-}
-
-async function main() {
-    let args = process.argv.slice(2);
-    try {
-        py = await loadPyodide({
-            args,
-            env: Object.assign({
-                PYTHONINSPECT: "",
-            }, process.env, { HOME: process.cwd() }),
-            fullStdLib: false,
-            _node_mounts: dirsToMount(),
-            // Strip out messages written to stderr while loading
-            // After Pyodide is loaded we will replace stdstreams with setupStreams.
-            stderr(e) {
-                if (
-                    [
-                        "warning: no blob constructor, cannot create blobs with mimetypes",
-                        "warning: no BlobBuilder",
-                    ].includes(e.trim())
-                ) {
-                    return;
-                }
-                console.warn(e);
-            }
-        });
-    } catch (e) {
-        if (e.constructor.name !== "ExitStatus") {
-            throw e;
-        }
-        // If the user passed `--help`, `--version`, or a set of command line
-        // arguments that is invalid in some way, we will exit here.
-        process.exit(e.status);
-    }
-    py.setStdout();
-    py.setStderr();
-    let sideGlobals = py.runPython("{}");
-    function handleExit(code) {
-        if (code === undefined) {
-            code = 0;
-        }
-        if (py._module._Py_FinalizeEx() < 0) {
-            code = 120;
-        }
-        // It's important to call `process.exit` immediately after
-        // `_Py_FinalizeEx` because otherwise any asynchronous tasks still
-        // scheduled will segfault.
-        process.exit(code);
-    };
-    sideGlobals.set("handleExit", handleExit);
-
-    py.runPython(
-        `
-        from pyodide._package_loader import SITE_PACKAGES, should_load_dynlib
-        from pyodide.ffi import to_js
-        import re
-        dynlibs_to_load = to_js([
-            str(path) for path in SITE_PACKAGES.glob("**/*.so*")
-            if should_load_dynlib(path)
-        ])
-        `,
-        { globals: sideGlobals }
-    );
-    const dynlibs = sideGlobals.get("dynlibs_to_load");
-    for (const dynlib of dynlibs) {
-        try {
-            await py._module.API.loadDynlib(dynlib);
-        } catch(e) {
-            console.error("Failed to load lib ", dynlib);
-            console.error(e);
-        }
+# Macs come with FreeBSD coreutils which doesn't have the -s option
+# so feature detect and work around it.
+if which grealpath > /dev/null; then
+    # It has brew installed gnu core utils, use that
+    REALPATH="grealpath -s"
+elif which realpath > /dev/null && realpath --version > /dev/null 2> /dev/null && realpath --version | grep GNU > /dev/null; then
+    # realpath points to GNU realpath so use it.
+    REALPATH="realpath -s"
+else
+    # Shim for macs without GNU coreutils
+    abs_path () {
+        echo "$(cd "$(dirname "$1")" || exit; pwd)/$(basename "$1")"
     }
-    // Warning: this sounds like it might not do anything important, but it
-    // fills in the GOT. There can be segfaults if we leave it out.
-    // See https://github.com/emscripten-core/emscripten/issues/22052
-    // TODO: Fix Emscripten so this isn't needed
-    py._module.reportUndefinedSymbols();
+    REALPATH=abs_path
+fi
 
-    py.runPython(
-        `
-        import asyncio
-        # Keep the event loop alive until all tasks are finished, or SystemExit or
-        # KeyboardInterupt is raised.
-        loop = asyncio.get_event_loop()
-        # Make sure we don't run _no_in_progress_handler before we finish _run_main.
-        loop._in_progress += 1
-        loop._no_in_progress_handler = handleExit
-        loop._system_exit_handler = handleExit
-        loop._keyboard_interrupt_handler = lambda: handleExit(130)
 
-        # Make shutil.get_terminal_size tell the terminal size accurately.
-        import shutil
-        from js.process import stdout
-        import os
-        def get_terminal_size(fallback=(80, 24)):
-            columns = getattr(stdout, "columns", None)
-            rows = getattr(stdout, "rows", None)
-            if columns is None:
-                columns = fallback[0]
-            if rows is None:
-                rows = fallback[1]
-            return os.terminal_size((columns, rows))
-        shutil.get_terminal_size = get_terminal_size
-        `,
-        { globals: sideGlobals }
-    );
+RESOLVED_DIR=$(dirname $(realpath "$0"))
 
-    let errcode;
-    try {
-        errcode = py._module._run_main();
-    } catch (e) {
-        if (e.constructor.name === "ExitStatus") {
-            process.exit(e.status);
-        }
-        py._api.fatal_error(e);
-    }
-    if (errcode) {
-        process.exit(errcode);
-    }
-    py.runPython("loop._decrement_in_progress()", { globals: sideGlobals });
-}
-main().catch((e) => {
-    console.error(e);
-    process.exit(1);
-});
+exec node "$ARGS" $RESOLVED_DIR/python_cli_entry.js --this-program="$($REALPATH "$0")" "$@"