ui: simplify/shorten error messages (#3730)

* ui: simplify/shorten error messages

* address efiop's review

dvc/command/run.py

@@ -54,7 +54,7 @@ def run(self):
                 name=self.args.name,
             )
         except DvcException:
-            logger.exception("failed to run command")
+            logger.exception("")
             return 1
 
         return 0

dvc/exceptions.py

@@ -1,11 +1,16 @@
 """Exceptions raised by the dvc."""
+from funcy import first
 
 from dvc.utils import relpath, format_link
 
 
 class DvcException(Exception):
     """Base class for all dvc exceptions."""
 
+    def __init__(self, msg, *args):
+        assert msg
+        super().__init__(msg, *args)
+
 
 class InvalidArgumentError(ValueError, DvcException):
     """Thrown if arguments are invalid."""
@@ -23,13 +28,15 @@ class OutputDuplicationError(DvcException):
     def __init__(self, output, stages):
         assert isinstance(output, str)
         assert all(hasattr(stage, "relpath") for stage in stages)
-        msg = (
-            "file/directory '{}' is specified as an output in more than one "
-            "stage: \n{}\n"
-            "This is not allowed. Consider using a different output name."
-        ).format(
-            output, "\n".join("\t{}".format(s.addressing) for s in stages)
-        )
+        if len(stages) == 1:
+            msg = "output '{}' is already specified in {}.".format(
+                output, first(stages)
+            )
+        else:
+            msg = "output '{}' is already specified in stages:\n{}".format(
+                output,
+                "\n".join("\t- {}".format(s.addressing) for s in stages),
+            )
         super().__init__(msg)
         self.stages = stages
         self.output = output
@@ -81,10 +88,7 @@ class CircularDependencyError(DvcException):
     def __init__(self, dependency):
         assert isinstance(dependency, str)
 
-        msg = (
-            "file/directory '{}' is specified as an output and as a "
-            "dependency."
-        )
+        msg = "'{}' is specified as an output and as a dependency."
         super().__init__(msg.format(dependency))
 
 
@@ -133,22 +137,16 @@ def __init__(self):
 class CyclicGraphError(DvcException):
     def __init__(self, stages):
         assert isinstance(stages, list)
-        stages = "\n".join(
-            "\t- {}".format(stage.addressing) for stage in stages
-        )
-        msg = (
-            "you've introduced a cycle in your pipeline that involves "
-            "the following stages:"
-            "\n"
-            "{stages}".format(stages=stages)
+        msg = "Pipeline has a cycle involving: {}.".format(
+            ", ".join(s.addressing for s in stages)
         )
         super().__init__(msg)
 
 
 class ConfirmRemoveError(DvcException):
     def __init__(self, path):
         super().__init__(
-            "unable to remove '{}' without a confirmation from the user. Use "
+            "unable to remove '{}' without a confirmation. Use "
             "`-f` to force.".format(path)
         )
 

dvc/main.py

@@ -6,7 +6,7 @@
 from dvc import analytics
 from dvc.cli import parse_args
 from dvc.config import ConfigError
-from dvc.exceptions import DvcParserError
+from dvc.exceptions import DvcParserError, DvcException
 from dvc.exceptions import NotDvcRepoError
 from dvc.external_repo import clean_repos
 from dvc.logger import disable_other_loggers, FOOTER
@@ -58,6 +58,9 @@ def main(argv=None):
         ret = 253
     except DvcParserError:
         ret = 254
+    except DvcException:
+        ret = 255
+        logger.exception("")
     except Exception as exc:  # pylint: disable=broad-except
         if isinstance(exc, OSError) and exc.errno == errno.EMFILE:
             logger.exception(

dvc/stage/__init__.py

@@ -617,8 +617,9 @@ def _run(self):
             if old_handler:
                 signal.signal(signal.SIGINT, old_handler)
 
-        if (p is None) or (p.returncode != 0):
-            raise StageCmdFailedError(self)
+        retcode = None if not p else p.returncode
+        if retcode != 0:
+            raise StageCmdFailedError(self, retcode)
 
     @rwlocked(read=["deps"], write=["outs"])
     def run(

dvc/stage/exceptions.py

@@ -2,8 +2,10 @@
 
 
 class StageCmdFailedError(DvcException):
-    def __init__(self, stage):
-        msg = "{} cmd '{}' failed".format(stage, stage.cmd)
+    def __init__(self, stage, status=None):
+        msg = "failed to run: {}".format(stage.cmd)
+        if status is not None:
+            msg += ", exited with {}".format(status)
         super().__init__(msg)
 
 
@@ -88,9 +90,7 @@ def __init__(self, missing_files):
 class StageNotFound(KeyError, DvcException):
     def __init__(self, file, name):
         super().__init__(
-            "Stage with '{}' name not found inside '{}' file".format(
-                name, file.relpath
-            )
+            "Stage '{}' not found inside '{}' file".format(name, file.relpath)
         )
 
 
@@ -105,7 +105,7 @@ def __init__(self, file):
 class DuplicateStageName(DvcException):
     def __init__(self, name, file):
         super().__init__(
-            "Stage with name '{name}' already exists in '{relpath}'.".format(
+            "Stage '{name}' already exists in '{relpath}'.".format(
                 name=name, relpath=file.relpath
             )
         )