Issue #25768: Make compileall functions return booleans and document

the return values as well as test them.

Thanks to Nicholas Chammas for the bug report and initial patch.

Doc/library/compileall.rst

@@ -103,7 +103,8 @@ Public functions
 .. function:: compile_dir(dir, maxlevels=10, ddir=None, force=False, rx=None, quiet=0, legacy=False, optimize=-1, workers=1)
 
    Recursively descend the directory tree named by *dir*, compiling all :file:`.py`
-   files along the way.
+   files along the way. Return a true value if all the files compiled successfully,
+   and a false value otherwise.
 
    The *maxlevels* parameter is used to limit the depth of the recursion; it
    defaults to ``10``.
@@ -155,7 +156,8 @@ Public functions
 
 .. function:: compile_file(fullname, ddir=None, force=False, rx=None, quiet=0, legacy=False, optimize=-1)
 
-   Compile the file with path *fullname*.
+   Compile the file with path *fullname*. Return a true value if the file
+   compiled successfully, and a false value otherwise.
 
    If *ddir* is given, it is prepended to the path to the file being compiled
    for use in compilation time tracebacks, and is also compiled in to the
@@ -191,8 +193,10 @@ Public functions
 
 .. function:: compile_path(skip_curdir=True, maxlevels=0, force=False, quiet=0, legacy=False, optimize=-1)
 
-   Byte-compile all the :file:`.py` files found along ``sys.path``. If
+   Byte-compile all the :file:`.py` files found along ``sys.path``. Return a
-   *skip_curdir* is true (the default), the current directory is not included
+   true value if all the files compiled successfully, and a false value otherwise.
+
+   If *skip_curdir* is true (the default), the current directory is not included
    in the search.  All other parameters are passed to the :func:`compile_dir`
    function.  Note that unlike the other compile functions, ``maxlevels``
    defaults to ``0``.

Doc/whatsnew/3.6.rst

@@ -230,6 +230,11 @@ that may require changes to your code.
 Changes in the Python API
 -------------------------
 
+* The functions in the :mod:`compileall` module now return booleans instead
+  of ``1`` or ``0`` to represent success or failure, respectively. Thanks to
+  booleans being a subclass of integers, this should only be an issue if you
+  were doing identity checks for ``1`` or ``0``. See :issue:`25768`.
+
 * Reading the :attr:`~urllib.parse.SplitResult.port` attribute of
   :func:`urllib.parse.urlsplit` and :func:`~urllib.parse.urlparse` results
   now raises :exc:`ValueError` for out-of-range values, rather than

Lib/compileall.py

@@ -68,7 +68,7 @@ def compile_dir(dir, maxlevels=10, ddir=None, force=False, rx=None,
     """
     files = _walk_dir(dir, quiet=quiet, maxlevels=maxlevels,
                       ddir=ddir)
-    success = 1
+    success = True
     if workers is not None and workers != 1 and ProcessPoolExecutor is not None:
         if workers < 0:
             raise ValueError('workers must be greater or equal to 0')
@@ -81,12 +81,12 @@ def compile_dir(dir, maxlevels=10, ddir=None, force=False, rx=None,
                                            legacy=legacy,
                                            optimize=optimize),
                                    files)
-            success = min(results, default=1)
+            success = min(results, default=True)
     else:
         for file in files:
             if not compile_file(file, ddir, force, rx, quiet,
                                 legacy, optimize):
-                success = 0
+                success = False
     return success
 
 def compile_file(fullname, ddir=None, force=False, rx=None, quiet=0,
@@ -104,7 +104,7 @@ def compile_file(fullname, ddir=None, force=False, rx=None, quiet=0,
     legacy:    if True, produce legacy pyc paths instead of PEP 3147 paths
     optimize:  optimization level or -1 for level of the interpreter
     """
-    success = 1
+    success = True
     name = os.path.basename(fullname)
     if ddir is not None:
         dfile = os.path.join(ddir, name)
@@ -144,7 +144,7 @@ def compile_file(fullname, ddir=None, force=False, rx=None, quiet=0,
                 ok = py_compile.compile(fullname, cfile, dfile, True,
                                         optimize=optimize)
             except py_compile.PyCompileError as err:
-                success = 0
+                success = False
                 if quiet >= 2:
                     return success
                 elif quiet:
@@ -157,7 +157,7 @@ def compile_file(fullname, ddir=None, force=False, rx=None, quiet=0,
                 msg = msg.decode(sys.stdout.encoding)
                 print(msg)
             except (SyntaxError, UnicodeError, OSError) as e:
-                success = 0
+                success = False
                 if quiet >= 2:
                     return success
                 elif quiet:
@@ -167,7 +167,7 @@ def compile_file(fullname, ddir=None, force=False, rx=None, quiet=0,
                 print(e.__class__.__name__ + ':', e)
             else:
                 if ok == 0:
-                    success = 0
+                    success = False
     return success
 
 def compile_path(skip_curdir=1, maxlevels=0, force=False, quiet=0,
@@ -183,7 +183,7 @@ def compile_path(skip_curdir=1, maxlevels=0, force=False, quiet=0,
     legacy: as for compile_dir() (default False)
     optimize: as for compile_dir() (default -1)
     """
-    success = 1
+    success = True
     for dir in sys.path:
         if (not dir or dir == os.curdir) and skip_curdir:
             if quiet < 2:

Lib/test/test_compileall.py

@@ -1,6 +1,7 @@
 import sys
 import compileall
 import importlib.util
+import test.test_importlib.util
 import os
 import pathlib
 import py_compile
@@ -40,6 +41,11 @@ class CompileallTests(unittest.TestCase):
     def tearDown(self):
         shutil.rmtree(self.directory)
 
+    def add_bad_source_file(self):
+        self.bad_source_path = os.path.join(self.directory, '_test_bad.py')
+        with open(self.bad_source_path, 'w') as file:
+            file.write('x (\n')
+
     def data(self):
         with open(self.bc_path, 'rb') as file:
             data = file.read(8)
@@ -78,15 +84,31 @@ class CompileallTests(unittest.TestCase):
                 os.unlink(fn)
             except:
                 pass
-        compileall.compile_file(self.source_path, force=False, quiet=True)
+        self.assertTrue(compileall.compile_file(self.source_path,
+                                                force=False, quiet=True))
         self.assertTrue(os.path.isfile(self.bc_path) and
                         not os.path.isfile(self.bc_path2))
         os.unlink(self.bc_path)
-        compileall.compile_dir(self.directory, force=False, quiet=True)
+        self.assertTrue(compileall.compile_dir(self.directory, force=False,
+                                               quiet=True))
         self.assertTrue(os.path.isfile(self.bc_path) and
                         os.path.isfile(self.bc_path2))
         os.unlink(self.bc_path)
         os.unlink(self.bc_path2)
+        # Test against bad files
+        self.add_bad_source_file()
+        self.assertFalse(compileall.compile_file(self.bad_source_path,
+                                                 force=False, quiet=2))
+        self.assertFalse(compileall.compile_dir(self.directory,
+                                                force=False, quiet=2))
+
+    def test_compile_path(self):
+        self.assertTrue(compileall.compile_path(quiet=2))
+
+        with test.test_importlib.util.import_state(path=[self.directory]):
+            self.add_bad_source_file()
+            self.assertFalse(compileall.compile_path(skip_curdir=False,
+                                                     force=True, quiet=2))
 
     def test_no_pycache_in_non_package(self):
         # Bug 8563 reported that __pycache__ directories got created by

Misc/ACKS

@@ -235,6 +235,7 @@ Octavian Cerna
 Michael Cetrulo
 Dave Chambers
 Pascal Chambon
+Nicholas Chammas
 John Chandler
 Hye-Shik Chang
 Jeffrey Chang

Misc/NEWS

@@ -123,6 +123,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #25768: Have the functions in compileall return booleans instead of
+  ints and add proper documentation and tests for the return values.
+
 - Issue #24103: Fixed possible use after free in ElementTree.XMLPullParser.
 
 - Issue #25860: os.fwalk() no longer skips remaining directories when error