Restore progress reporting to extractcode #1996

Do not consume extract events generators in a list. This prohinited
the progressive dispatch of "events" being generated to provide
progress display in the CLI. Instead we now yield events again as they
are created and accumulate events for leter reprocessing if the
option to replace originals has been selected.

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

Author: pombredanne

src/extractcode/extract.py

@@ -113,7 +113,7 @@ def extract(location, kinds=extractcode.default_kinds, recurse=False, replace_or
        is True.
 
     If `recurse` is True, extract recursively archives nested inside other
-    archives If `recurse` is false, then do not extract further an already
+    archives. If `recurse` is false, then do not extract further an already
     extracted archive identified by the corresponding extract suffix location.
 
     If `replace_originals` is True, the extracted archives are replaced by the
@@ -123,9 +123,16 @@ def extract(location, kinds=extractcode.default_kinds, recurse=False, replace_or
     if recurse and a nested archive is found, it is extracted to full depth
     first before resuming the file system walk.
     """
-    events = list(extract_files(location, kinds, recurse))
+    processed_events = []
+    processed_events_append = processed_events.append
+    for event in extract_files(location, kinds, recurse):
+        yield event
+        if replace_originals:
+            processed_events_append(event)
+
+    # move files around
     if replace_originals:
-        for xevent in reversed(events):
+        for xevent in reversed(processed_events):
             if xevent.done:
                 source = xevent.source
                 target = xevent.target
@@ -134,12 +141,22 @@ def extract(location, kinds=extractcode.default_kinds, recurse=False, replace_or
                 fileutils.delete(source)
                 fileutils.copytree(target, source)
                 fileutils.delete(target)
-    return events
+
 
 def extract_files(location, kinds=extractcode.default_kinds, recurse=False):
+    """
+    Extract the files found at `location`.
+
+    Extract only archives of a kind listed in the `kinds` kind tuple.
+
+    If `recurse` is True, extract recursively archives nested inside other
+    archives. If `recurse` is false, then do not extract further an already
+    extracted archive identified by the corresponding extract suffix location.
+    """
     ignored = partial(ignore.is_ignored, ignores=ignore.default_ignores, unignores={})
     if TRACE:
         logger.debug('extract:start: %(location)r  recurse: %(recurse)r\n' % locals())
+
     abs_location = abspath(expanduser(location))
     for top, dirs, files in fileutils.walk(abs_location, ignored):
         if TRACE:
@@ -192,8 +209,8 @@ def extract_file(location, target, kinds=extractcode.default_kinds, verbose=Fals
     extractor = archive.get_extractor(location, kinds)
     if TRACE:
         logger.debug('extract_file: extractor: for: %(location)r with kinds: %(kinds)r : ' % locals()
-                     + getattr(extractor, '__module__', '')
-                     + '.' + getattr(extractor, '__name__', ''))
+                     +getattr(extractor, '__module__', '')
+                     +'.' + getattr(extractor, '__name__', ''))
     if extractor:
         yield ExtractEvent(location, target, done=False, warnings=[], errors=[])
         try:

tests/extractcode/data/extract/generator/c.zip

@@ -41,6 +41,7 @@
 from commoncode.system import on_linux
 from commoncode.system import on_windows
 from commoncode.system import py3
+from types import GeneratorType
 
 
 class TestExtract(FileBasedTesting):
@@ -1111,3 +1112,9 @@ def test_extract_zipslip_tar_posix(self):
 
         warns = [r.warnings for r in result if r.warnings]
         assert [] == warns
+
+    def test_extract_always_returns_a_generator_and_not_a_list(self):
+        # a test for #1996 to ensure that progress is displayed "progressively"
+        test_dir = self.get_test_loc('extract/generator', copy=True)
+        result = extract.extract(test_dir)
+        assert isinstance(result, GeneratorType)