Fix amalgamation script to work with python3-only environments (#444)

- Use sys.executable in Python scripts (amalgamate.py, cmake_build.py) instead of hardcoded 'python'
- Update shell scripts to prefer python3 over python with fallback
- Fix scripts/run_tests.py to detect python3 for CPython benchmarking

This fixes the issue where the amalgamation script fails on Linux systems
that only have python3 available and no 'python' symlink.

amalgamate.py

@@ -5,7 +5,7 @@ import sys
 import time
 from typing import List, Dict
 
-assert os.system("python prebuild.py") == 0
+assert os.system(f"{sys.executable} prebuild.py") == 0
 
 ROOT = 'include/pocketpy'
 PUBLIC_HEADERS = ['config.h', 'export.h', 'vmath.h', 'pocketpy.h']

build.sh

@@ -8,7 +8,7 @@ if ! type -P clang >/dev/null 2>&1; then
 fi
 
 echo "> Running prebuild.py... "
-python prebuild.py
+command -v python3 >/dev/null 2>&1 && python3 prebuild.py || python prebuild.py
 
 if [ $? -ne 0 ]; then
     echo "prebuild.py failed."

build_darwin_libs.sh

@@ -1,6 +1,9 @@
 set -e
 
-python amalgamate.py
+# Use python3 if available, otherwise fall back to python
+PYTHON=$(command -v python3 >/dev/null 2>&1 && echo python3 || echo python)
+
+$PYTHON amalgamate.py
 
 rm -rf build
 mkdir build
@@ -20,4 +23,4 @@ cmake --build . --config Release
 
 cd ../
 
-python scripts/merge_built_libraries.py build
+$PYTHON scripts/merge_built_libraries.py build

build_ios_libs.sh

@@ -1,6 +1,9 @@
 set -e
 
-python amalgamate.py
+# Use python3 if available, otherwise fall back to python
+PYTHON=$(command -v python3 >/dev/null 2>&1 && echo python3 || echo python)
+
+$PYTHON amalgamate.py
 
 rm -rf build
 mkdir build
@@ -27,8 +30,8 @@ cd ../
 
 HEADERS="amalgamated/pocketpy.h"
 
-python scripts/merge_built_libraries.py build/os64
-python scripts/merge_built_libraries.py build/simulatorarm64
+$PYTHON scripts/merge_built_libraries.py build/os64
+$PYTHON scripts/merge_built_libraries.py build/simulatorarm64
 
 xcodebuild -create-xcframework \
     -library build/os64/libpocketpy.a -headers $HEADERS \

build_web.sh

@@ -1,6 +1,9 @@
 set -e
 
-python prebuild.py
+# Use python3 if available, otherwise fall back to python
+PYTHON=$(command -v python3 >/dev/null 2>&1 && echo python3 || echo python)
+
+$PYTHON prebuild.py
 
 rm -rf web/lib
 mkdir web/lib

cmake_build.py

@@ -2,7 +2,7 @@ import os
 import sys
 import shutil
 
-assert os.system("python prebuild.py") == 0
+assert os.system(f"{sys.executable} prebuild.py") == 0
 
 if not os.path.exists("build"):
     os.mkdir("build")

run_profile.sh

@@ -1,6 +1,9 @@
 set -e
 
-python prebuild.py
+# Use python3 if available, otherwise fall back to python
+PYTHON=$(command -v python3 >/dev/null 2>&1 && echo python3 || echo python)
+
+$PYTHON prebuild.py
 
 SRC=$(find src/ -name "*.c")
 

run_tests.sh

@@ -1,12 +1,15 @@
 set -e
 
-python prebuild.py
+# Use python3 if available, otherwise fall back to python
+PYTHON=$(command -v python3 >/dev/null 2>&1 && echo python3 || echo python)
+
+$PYTHON prebuild.py
 
 SRC=$(find src/ -name "*.c")
 
 clang -std=c11 --coverage -O1 -Wfatal-errors -o main src2/main.c $SRC -Iinclude -DPK_ENABLE_OS=1 -lm -ldl -DNDEBUG
 
-python scripts/run_tests.py
+$PYTHON scripts/run_tests.py
 
 # if prev error exit
 if [ $? -ne 0 ]; then

scripts/run_tests.py

@@ -2,11 +2,14 @@ import os
 import sys
 import time
 import subprocess
+import shutil
 
 
 def test_file(filepath, cpython=False):
     if cpython:
-        return os.system("python " + filepath) == 0
+        # Use python3 if available, otherwise fall back to python
+        python_cmd = shutil.which("python3") or shutil.which("python") or "python"
+        return os.system(f"{python_cmd} {filepath}") == 0
     if sys.platform == 'win32':
         code = os.system("main.exe " + filepath)
     else: