target/{host,ssh}: Align push/pull with cp/mv behaviour

When pushing or pulling a folder, replicate the mv/cp/scp/adb behaviour,
which is:
    * splitting the destination into (existing, new) components
    * if {new} component is empty, set it to the basename of the source.
    * mkdir {new} if necessary
    * merge the hierarchies of {src} and {existing}/{new}

devlib/host.py

@@ -64,20 +64,35 @@ class LocalConnection(ConnectionBase):
         self.unrooted = unrooted
         self.password = password
 
-    def push(self, sources, dest, timeout=None, as_root=False):  # pylint: disable=unused-argument
-        self.logger.debug('copying {} to {}'.format(sources, dest))
-        for source in sources:
-            shutil.copy(source, dest)
 
-    def pull(self, sources, dest, timeout=None, as_root=False): # pylint: disable=unused-argument
-        for source in sources:
+    def _copy_path(self, source, dest):
         self.logger.debug('copying {} to {}'.format(source, dest))
         if os.path.isdir(source):
-                # Use distutils to allow copying into an existing directory structure.
-                copy_tree(source, dest)
+            # Behave similarly as cp, scp, adb push, etc. by creating a new
+            # folder instead of merging hierarchies
+            if os.path.exists(dest):
+                dest = os.path.join(dest, os.path.basename(os.path.normpath(src)))
+
+            # Use distutils copy_tree since it behaves the same as
+            # shutils.copytree except that it won't fail if some folders
+            # already exist.
+            #
+            # Mirror the behavior of all other targets which only copy the
+            # content without metadata
+            copy_tree(source, dest, preserve_mode=False, preserve_times=False)
         else:
             shutil.copy(source, dest)
 
+    def _copy_paths(self, sources, dest):
+        for source in sources:
+            self._copy_path(source, dest)
+
+    def push(self, sources, dest, timeout=None, as_root=False):  # pylint: disable=unused-argument
+        self._copy_paths(sources, dest)
+
+    def pull(self, sources, dest, timeout=None, as_root=False): # pylint: disable=unused-argument
+        self._copy_paths(sources, dest)
+
     # pylint: disable=unused-argument
     def execute(self, command, timeout=None, check_exit_code=True,
                 as_root=False, strip_colors=True, will_succeed=False):

devlib/utils/ssh.py

@@ -451,28 +451,45 @@ class SshConnection(SshConnectionBase):
         try:
             sftp.put(src, dst)
         # Maybe the dst was a folder
-        except OSError as e:
-            logger.debug('sftp transfer error: {}'.format(repr(e)))
-            # This might fail if the folder already exists
-            with contextlib.suppress(IOError):
-                sftp.mkdir(dst)
-
+        except OSError as orig_excep:
+            # If dst was an existing folder, we add the src basename to create
+            # a new destination for the file as cp would do
             new_dst = os.path.join(
                 dst,
                 os.path.basename(src),
             )
             logger.debug('Trying: {} -> {}'.format(src, new_dst))
+            try:
                 sftp.put(src, new_dst)
+            # This still failed, which either means:
+            # * There are some missing folders in the dirnames
+            # * Something else SFTP-related is wrong
+            except OSError as e:
+                # Raise the original exception, as it is closer to what the
+                # user asked in the first place
+                raise orig_excep
 
+    @classmethod
+    def _path_exists(cls, sftp, path):
+        try:
+            sftp.lstat(path)
+        except FileNotFoundError:
+            return False
+        else:
+            return True
 
     @classmethod
     def _push_folder(cls, sftp, src, dst):
         # Behave like the "mv" command or adb push: a new folder is created
-        # inside the destination folder, rather than merging the trees.
+        # inside the destination folder, rather than merging the trees, but
+        # only if the destination already exists. Otherwise, it is use as-is as
+        # the new hierarchy name.
+        if cls._path_exists(sftp, dst):
             dst = os.path.join(
                 dst,
                 os.path.basename(os.path.normpath(src)),
             )
+
         return cls._push_folder_internal(sftp, src, dst)
 
     @classmethod