Move misc. imports from command, make them lazy (#5214)

dvc/command/add.py

@@ -3,13 +3,17 @@ import logging
 
 from dvc.command import completion
 from dvc.command.base import CmdBase, append_doc_link
-from dvc.exceptions import DvcException, RecursiveAddingWhileUsingFilename
 
 logger = logging.getLogger(__name__)
 
 
 class CmdAdd(CmdBase):
     def run(self):
+        from dvc.exceptions import (
+            DvcException,
+            RecursiveAddingWhileUsingFilename,
+        )
+
         try:
             if len(self.args.targets) > 1 and self.args.file:
                 raise RecursiveAddingWhileUsingFilename()

dvc/command/dag.py

@@ -2,7 +2,6 @@ import argparse
 import logging
 
 from dvc.command.base import CmdBase, append_doc_link
-from dvc.stage import Stage
 
 logger = logging.getLogger(__name__)
 
@@ -53,6 +52,8 @@ def _collect_targets(repo, target, outs):
 def _transform(repo, outs):
     import networkx as nx
 
+    from dvc.stage import Stage
+
     def _relabel(node) -> str:
         return node.addressing if isinstance(node, Stage) else str(node)
 

dvc/command/experiments.py

@@ -13,8 +13,6 @@ from dvc.command.metrics import DEFAULT_PRECISION
 from dvc.command.repro import CmdRepro
 from dvc.command.repro import add_arguments as add_repro_arguments
 from dvc.exceptions import DvcException, InvalidArgumentError
-from dvc.repo.experiments import Experiments
-from dvc.scm.git import Git
 from dvc.utils.flatten import flatten
 
 logger = logging.getLogger(__name__)
@@ -109,6 +107,8 @@ def _collect_rows(
     sort_by=None,
     sort_order=None,
 ):
+    from dvc.scm.git import Git
+
     if sort_by:
         if sort_by in metric_names:
             sort_type = "metrics"
@@ -601,6 +601,7 @@ class CmdExperimentsPull(CmdBase):
 
 def add_parser(subparsers, parent_parser):
     EXPERIMENTS_HELP = "Commands to run and compare experiments."
+    LAST_CHECKPOINT = ":last"
 
     experiments_parser = subparsers.add_parser(
         "experiments",
@@ -831,7 +832,7 @@ def add_parser(subparsers, parent_parser):
         "-r",
         "--rev",
         type=str,
-        default=Experiments.LAST_CHECKPOINT,
+        default=LAST_CHECKPOINT,
         dest="checkpoint_resume",
         help=(
             "Continue the specified checkpoint experiment. "

dvc/command/repro.py

@@ -5,7 +5,6 @@ from dvc.command import completion
 from dvc.command.base import CmdBase, append_doc_link
 from dvc.command.metrics import _show_metrics
 from dvc.command.status import CmdDataStatus
-from dvc.dvcfile import PIPELINE_FILE
 
 logger = logging.getLogger(__name__)
 
@@ -50,7 +49,7 @@ def add_arguments(repro_parser):
     repro_parser.add_argument(
         "targets",
         nargs="*",
-        help=f"Stages to reproduce. '{PIPELINE_FILE}' by default.",
+        help="Stages to reproduce. 'dvc.yaml' by default.",
     ).complete = completion.DVC_FILE
     repro_parser.add_argument(
         "-f",

dvc/command/version.py

@@ -2,13 +2,14 @@ import argparse
 import logging
 
 from dvc.command.base import CmdBaseNoRepo, append_doc_link
-from dvc.info import get_dvc_info
 
 logger = logging.getLogger(__name__)
 
 
 class CmdVersion(CmdBaseNoRepo):
     def run(self):
+        from dvc.info import get_dvc_info
+
         dvc_info = get_dvc_info()
         logger.info(dvc_info)
         return 0

dvc/dvcfile.py

@@ -14,7 +14,6 @@ from dvc.stage.exceptions import (
     StageFileFormatError,
     StageFileIsNotDvcFileError,
 )
-from dvc.stage.loader import SingleStageLoader, StageLoader
 from dvc.utils import relpath
 from dvc.utils.collections import apply_diff
 from dvc.utils.serialize import (
@@ -137,16 +136,17 @@ class FileMixin:
 
 class SingleStageFile(FileMixin):
     from dvc.schema import COMPILED_SINGLE_STAGE_SCHEMA as SCHEMA
+    from dvc.stage.loader import SingleStageLoader as LOADER
 
     @property
     def stage(self):
         data, raw = self._load()
-        return SingleStageLoader.load_stage(self, data, raw)
+        return self.LOADER.load_stage(self, data, raw)
 
     @property
     def stages(self):
         data, raw = self._load()
-        return SingleStageLoader(self, data, raw)
+        return self.LOADER(self, data, raw)
 
     def dump(self, stage, **kwargs):
         """Dumps given stage appropriately in the dvcfile."""
@@ -177,6 +177,7 @@ class PipelineFile(FileMixin):
     """Abstraction for pipelines file, .yaml + .lock combined."""
 
     from dvc.schema import COMPILED_MULTI_STAGE_SCHEMA as SCHEMA
+    from dvc.stage.loader import StageLoader as LOADER
 
     @property
     def _lockfile(self):
@@ -239,7 +240,7 @@ class PipelineFile(FileMixin):
     def stages(self):
         data, _ = self._load()
         lockfile_data = self._lockfile.load()
-        return StageLoader(self, data, lockfile_data)
+        return self.LOADER(self, data, lockfile_data)
 
     def remove(self, force=False):
         if not force:

dvc/exceptions.py

@@ -3,8 +3,6 @@ from typing import List
 
 from funcy import first
 
-from dvc.utils import error_link, format_link, relpath
-
 
 class DvcException(Exception):
     """Base class for all dvc exceptions."""
@@ -51,6 +49,8 @@ class OutputNotFoundError(DvcException):
     """
 
     def __init__(self, output, repo=None):
+        from dvc.utils import relpath
+
         self.output = output
         self.repo = repo
         super().__init__(
@@ -253,6 +253,8 @@ class DvcIgnoreInCollectedDirError(DvcException):
 
 class GitHookAlreadyExistsError(DvcException):
     def __init__(self, hook_name):
+        from dvc.utils import format_link
+
         super().__init__(
             "Hook '{}' already exists. Please refer to {} for more "
             "info.".format(
@@ -277,6 +279,8 @@ class UploadError(DvcException):
 
 class CheckoutError(DvcException):
     def __init__(self, target_infos, stats=None):
+        from dvc.utils import error_link
+
         self.target_infos = target_infos
         self.stats = stats
         targets = [str(t) for t in target_infos]
@@ -302,6 +306,8 @@ class NoRemoteInExternalRepoError(DvcException):
 
 class NoOutputInExternalRepoError(DvcException):
     def __init__(self, path, external_repo_path, external_repo_url):
+        from dvc.utils import relpath
+
         super().__init__(
             "Output '{}' not found in target repository '{}'".format(
                 relpath(path, external_repo_path), external_repo_url
@@ -332,6 +338,8 @@ class PathMissingError(DvcException):
 
 class RemoteCacheRequiredError(DvcException):
     def __init__(self, path_info):
+        from dvc.utils import format_link
+
         super().__init__(
             (
                 "Current operation was unsuccessful because '{}' requires "
@@ -366,6 +374,8 @@ class MergeError(DvcException):
 
 
 class CacheLinkError(DvcException):
+    from dvc.utils import format_link
+
     SUPPORT_LINK = "See {} for more information.".format(
         format_link(
             "https://dvc.org/doc/user-guide/troubleshooting#cache-types"

dvc/utils/flatten.py

@@ -1,9 +1,10 @@
-import flatten_dict
-
-
 def flatten(d):
+    import flatten_dict
+
     return flatten_dict.flatten(d, reducer="dot")
 
 
 def unflatten(d):
+    import flatten_dict
+
     return flatten_dict.unflatten(d, splitter="dot")