Set sys._base_executable properly

Author: msimacek

graalpython/com.oracle.graal.python.shell/src/com/oracle/graal/python/shell/GraalPythonMain.java

@@ -872,13 +872,14 @@ private static String toAbsolutePath(String executable) {
 
     // Rough equivalent of CPython's pyvenv.cfg logic in Modules/getpath.py
     private void findAndApplyVenvCfg(Builder contextBuilder, String executable) {
-        Path binDir;
+        Path executablePath;
         try {
-            binDir = Paths.get(executable).getParent();
+            executablePath = Paths.get(executable);
         } catch (InvalidPathException e) {
-            log("cannot determine the parent directory of the executable");
+            log("cannot determine path of the executable");
             return;
         }
+        Path binDir = executablePath.getParent();
         if (binDir == null) {
             log("parent directory of the executable does not exist");
             return;
@@ -906,23 +907,44 @@ private void findAndApplyVenvCfg(Builder contextBuilder, String executable) {
                 }
                 String name = parts[0].trim();
                 if (name.equals("home")) {
-                    Path homeProperty = Paths.get(parts[1].trim());
-                    /*
-                     * (tfel): According to PEP 405, the home key is the directory of the Python
-                     * executable from which this virtual environment was created, that is, it
-                     * usually ends with "/bin" on a Unix system. On Windows, the base Python should
-                     * be in the top-level directory or under "\Scripts". To support running from
-                     * Maven artifacts where we don't have a working executable, we patched our
-                     * shipped venv module to set the home path without a "/bin" or "\\Scripts"
-                     * suffix, so we explicitly check for those two subfolder cases and otherwise
-                     * assume the home key is directly pointing to the Python home.
-                     */
-                    if (homeProperty.endsWith("bin") || homeProperty.endsWith("Scripts")) {
-                        homeProperty = homeProperty.getParent();
-                    }
                     try {
-                        contextBuilder.option("python.PythonHome", homeProperty.toString());
-                    } catch (NullPointerException ex) {
+                        Path homeProperty = Paths.get(parts[1].trim());
+                        Path graalpyHome = homeProperty;
+                        /*
+                         * (tfel): According to PEP 405, the home key is the directory of the Python
+                         * executable from which this virtual environment was created, that is, it
+                         * usually ends with "/bin" on a Unix system. On Windows, the base Python
+                         * should be in the top-level directory or under "\Scripts". To support
+                         * running from Maven artifacts where we don't have a working executable, we
+                         * patched our shipped venv module to set the home path without a "/bin" or
+                         * "\\Scripts" suffix, so we explicitly check for those two subfolder cases
+                         * and otherwise assume the home key is directly pointing to the Python
+                         * home.
+                         */
+                        if (graalpyHome.endsWith("bin") || graalpyHome.endsWith("Scripts")) {
+                            graalpyHome = graalpyHome.getParent();
+                        }
+                        contextBuilder.option("python.PythonHome", graalpyHome.toString());
+                        /*
+                         * First try to resolve symlinked executables, since that may be more
+                         * accurate than assuming the executable in 'home'.
+                         */
+                        Path baseExecutable = null;
+                        try {
+                            Path realPath = executablePath.toRealPath();
+                            if (!realPath.equals(executablePath.toAbsolutePath())) {
+                                baseExecutable = realPath;
+                            }
+                        } catch (IOException ex) {
+                            // Ignore
+                        }
+                        if (baseExecutable == null) {
+                            baseExecutable = homeProperty.resolve(executablePath.getFileName());
+                        }
+                        if (Files.exists(baseExecutable)) {
+                            contextBuilder.option("python.BaseExecutable", baseExecutable.toString());
+                        }
+                    } catch (NullPointerException | InvalidPathException ex) {
                         // NullPointerException covers the possible null result of getParent()
                         warn("Could not set PYTHONHOME according to the pyvenv.cfg file.");
                     }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/SysModuleBuiltins.java

@@ -655,8 +655,10 @@ public void postInitialize0(Python3Core core) {
         TruffleString capiHome = context.getCAPIHome();
 
         if (!ImageInfo.inImageBuildtimeCode()) {
-            sys.setAttribute(tsLiteral("executable"), context.getOption(PythonOptions.Executable));
-            sys.setAttribute(tsLiteral("_base_executable"), context.getOption(PythonOptions.Executable));
+            TruffleString executable = context.getOption(PythonOptions.Executable);
+            TruffleString baseExecutable = context.getOption(PythonOptions.BaseExecutable);
+            sys.setAttribute(tsLiteral("executable"), executable);
+            sys.setAttribute(tsLiteral("_base_executable"), baseExecutable.isEmpty() ? executable : baseExecutable);
         }
         sys.setAttribute(tsLiteral("dont_write_bytecode"), context.getOption(PythonOptions.DontWriteBytecodeFlag));
         TruffleString pycachePrefix = context.getOption(PythonOptions.PyCachePrefix);

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/PythonOptions.java

@@ -315,9 +315,12 @@ private PythonOptions() {
     @Option(category = OptionCategory.EXPERT, usageSyntax = "<height>", help = "Set by the launcher to the terminal height.") //
     public static final OptionKey<Integer> TerminalHeight = new OptionKey<>(25);
 
-    @Option(category = OptionCategory.EXPERT, usageSyntax = "<path>", help = "The sys.executable path. Set by the launcher, but can may need to be overridden in certain special situations.", stability = OptionStability.STABLE) //
+    @Option(category = OptionCategory.EXPERT, usageSyntax = "<path>", help = "The sys.executable path. Set by the launcher, but may need to be overridden in certain special situations.", stability = OptionStability.STABLE) //
     public static final OptionKey<TruffleString> Executable = new OptionKey<>(T_EMPTY_STRING, TS_OPTION_TYPE);
 
+    @Option(category = OptionCategory.EXPERT, usageSyntax = "<path>", help = "The sys._base_executable path. Set by the launcher, but may need to be overridden in certain special situations.", stability = OptionStability.STABLE) //
+    public static final OptionKey<TruffleString> BaseExecutable = new OptionKey<>(T_EMPTY_STRING, TS_OPTION_TYPE);
+
     @Option(category = OptionCategory.EXPERT, usageSyntax = "<cmdPart>[" + J_STRING_LIST_SEPARATOR +
                     "<cmdPart>]", help = "The executed command list as string joined by the executable list separator char. This must always correspond to the real, valid command list used to run GraalPy.") //
     public static final OptionKey<TruffleString> ExecutableList = new OptionKey<>(T_EMPTY_STRING, TS_OPTION_TYPE);