cmd: imports lazy (#5226)

They are not a major pain point though

dvc/command/check_ignore.py

@@ -3,7 +3,6 @@ import logging
 
 from dvc.command import completion
 from dvc.command.base import CmdBase, append_doc_link
-from dvc.exceptions import DvcException
 
 logger = logging.getLogger(__name__)
 
@@ -55,6 +54,8 @@ class CmdCheckIgnore(CmdBase):
         return ret
 
     def _check_args(self):
+        from dvc.exceptions import DvcException
+
         if not self.args.stdin and not self.args.targets:
             raise DvcException("`targets` or `--stdin` needed")
 

dvc/command/checkout.py

@@ -7,7 +7,6 @@ import colorama
 from dvc.command import completion
 from dvc.command.base import CmdBase, append_doc_link
 from dvc.exceptions import CheckoutError
-from dvc.utils.humanize import get_summary
 
 logger = logging.getLogger(__name__)
 
@@ -39,6 +38,8 @@ def log_changes(stats):
 
 class CmdCheckout(CmdBase):
     def run(self):
+        from dvc.utils.humanize import get_summary
+
         stats, exc = None, None
         try:
             stats = self.repo.checkout(

dvc/command/commit.py

@@ -3,13 +3,14 @@ import logging
 
 from dvc.command import completion
 from dvc.command.base import CmdBase, append_doc_link
-from dvc.exceptions import DvcException
 
 logger = logging.getLogger(__name__)
 
 
 class CmdCommit(CmdBase):
     def run(self):
+        from dvc.exceptions import DvcException
+
         if not self.args.targets:
             self.args.targets = [None]
 

dvc/command/data_sync.py

@@ -3,25 +3,28 @@ import logging
 
 from dvc.command import completion
 from dvc.command.base import CmdBase, append_doc_link
-from dvc.command.checkout import log_changes
-from dvc.exceptions import CheckoutError, DvcException
-from dvc.utils.humanize import get_summary
 
 logger = logging.getLogger(__name__)
 
 
 class CmdDataBase(CmdBase):
     def log_summary(self, stats):
+        from dvc.utils.humanize import get_summary
+
         default_msg = "Everything is up to date."
         logger.info(get_summary(stats.items()) or default_msg)
 
 
 class CmdDataPull(CmdDataBase):
     def log_summary(self, stats):
+        from dvc.command.checkout import log_changes
+
         log_changes(stats)
         super().log_summary(stats)
 
     def run(self):
+        from dvc.exceptions import CheckoutError, DvcException
+
         try:
             stats = self.repo.pull(
                 targets=self.args.targets,
@@ -46,6 +49,8 @@ class CmdDataPull(CmdDataBase):
 
 class CmdDataPush(CmdDataBase):
     def run(self):
+        from dvc.exceptions import DvcException
+
         try:
             processed_files_count = self.repo.push(
                 targets=self.args.targets,
@@ -68,6 +73,8 @@ class CmdDataPush(CmdDataBase):
 
 class CmdDataFetch(CmdDataBase):
     def run(self):
+        from dvc.exceptions import DvcException
+
         try:
             processed_files_count = self.repo.fetch(
                 targets=self.args.targets,

dvc/command/destroy.py

@@ -3,13 +3,14 @@ import logging
 
 import dvc.prompt as prompt
 from dvc.command.base import CmdBase, append_doc_link
-from dvc.exceptions import DvcException
 
 logger = logging.getLogger(__name__)
 
 
 class CmdDestroy(CmdBase):
     def run(self):
+        from dvc.exceptions import DvcException
+
         try:
             statement = (
                 "This will destroy all information about your pipelines,"

dvc/command/diff.py

@@ -7,7 +7,6 @@ import colorama
 
 from dvc.command import completion
 from dvc.command.base import CmdBase, append_doc_link
-from dvc.exceptions import DvcException
 
 logger = logging.getLogger(__name__)
 
@@ -127,6 +126,8 @@ class CmdDiff(CmdBase):
         return "\n\n".join(groups)
 
     def run(self):
+        from dvc.exceptions import DvcException
+
         try:
             diff = self.repo.diff(
                 self.args.a_rev, self.args.b_rev, self.args.targets