fs: do not use DvcException in filesystems

* Refactor check_requires, move UI messages to dvc.cli
* Refactor link related error

dvc/cli/__init__.py

@@ -39,7 +39,38 @@ def parse_args(argv=None):
 def _log_exceptions(exc: Exception):
     """Try to log some known exceptions, that are not DVCExceptions."""
     from dvc.objects.cache import DiskError
-    from dvc.utils import error_link
+    from dvc.objects.fs.base import RemoteMissingDepsError
+    from dvc.utils import error_link, format_link
+
+    if isinstance(exc, RemoteMissingDepsError):
+        from dvc.utils.pkg import PKG
+
+        proto = exc.protocol
+        by_pkg = {
+            "pip": f"pip install 'dvc[{proto}]'",
+            "conda": f"conda install -c conda-forge dvc-{proto}",
+        }
+
+        cmd = by_pkg.get(PKG)
+        if cmd:
+            link = format_link("https://dvc.org/doc/install")
+            hint = (
+                f"To install dvc with those dependencies, run:\n"
+                "\n"
+                f"\t{cmd}\n"
+                "\n"
+                f"See {link} for more info."
+            )
+        else:
+            link = format_link("https://github.com/iterative/dvc/issues")
+            hint = f"\nPlease report this bug to {link}. Thank you!"
+
+        logger.exception(
+            f"URL '{exc.url}' is supported but requires these missing "
+            f"dependencies: {exc.missing_deps}. {hint}",
+            extra={"tb_only": True},
+        )
+        return
 
     if isinstance(exc, DiskError):
         from dvc.utils import relpath

dvc/objects/fs/base.py

@@ -19,8 +19,6 @@ from typing import (
 
 from funcy import cached_property
 
-from dvc.exceptions import DvcException
-
 from ..executors import ThreadPoolExecutor
 from ._callback import DEFAULT_CALLBACK, FsspecCallback
 
@@ -42,14 +40,32 @@ AnyFSPath = str
 Entry = Dict[str, Any]
 
 
-class RemoteActionNotImplemented(DvcException):
-    def __init__(self, action, scheme):
-        m = f"{action} is not supported for {scheme} remotes"
-        super().__init__(m)
+class LinkError(OSError):
+    def __init__(self, link: str, fs: "FileSystem", path: str) -> None:
+        import errno
+
+        super().__init__(
+            errno.EPERM,
+            f"{link} is not supported for {fs.protocol} by {type(fs)}",
+            path,
+        )
 
 
-class RemoteMissingDepsError(DvcException):
-    pass
+class RemoteMissingDepsError(Exception):
+    def __init__(
+        self,
+        fs: "FileSystem",
+        protocol: str,
+        url: str,
+        missing: List[str] = None,
+    ) -> None:
+        self.protocol = protocol
+        self.fs = fs
+        self.url = url
+        self.missing_deps = missing or []
+        super().__init__(
+            f"filesystem for '{protocol}': '{type(fs)}' missing dependencies"
+        )
 
 
 class FileSystem:
@@ -131,44 +147,18 @@ class FileSystem:
         return missing
 
     def _check_requires(self, **kwargs):
-        from dvc.utils import format_link
-        from dvc.utils.pkg import PKG
-
         from .scheme import Schemes
 
         missing = self.get_missing_deps()
         if not missing:
             return
 
+        proto = self.protocol
+        if proto == Schemes.WEBDAVS:
+            proto = Schemes.WEBDAV
+
         url = kwargs.get("url", f"{self.protocol}://")
-
-        scheme = self.protocol
-        if scheme == Schemes.WEBDAVS:
-            scheme = Schemes.WEBDAV
-
-        by_pkg = {
-            "pip": f"pip install 'dvc[{scheme}]'",
-            "conda": f"conda install -c conda-forge dvc-{scheme}",
-        }
-
-        cmd = by_pkg.get(PKG)
-        if cmd:
-            link = format_link("https://dvc.org/doc/install")
-            hint = (
-                f"To install dvc with those dependencies, run:\n"
-                "\n"
-                f"\t{cmd}\n"
-                "\n"
-                f"See {link} for more info."
-            )
-        else:
-            link = format_link("https://github.com/iterative/dvc/issues")
-            hint = f"Please report this bug to {link}. Thank you!"
-
-        raise RemoteMissingDepsError(
-            f"URL '{url}' is supported but requires these missing "
-            f"dependencies: {missing}. {hint}"
-        )
+        raise RemoteMissingDepsError(self, proto, url, missing)
 
     def isdir(self, path: AnyFSPath) -> bool:
         return self.fs.isdir(path)
@@ -295,19 +285,19 @@ class FileSystem:
         try:
             return self.fs.symlink(from_info, to_info)
         except AttributeError:
-            raise RemoteActionNotImplemented("symlink", self.protocol)
+            raise LinkError("symlink", self, from_info)
 
     def hardlink(self, from_info: AnyFSPath, to_info: AnyFSPath) -> None:
         try:
             return self.fs.hardlink(from_info, to_info)
         except AttributeError:
-            raise RemoteActionNotImplemented("hardlink", self.protocol)
+            raise LinkError("symlink", self, from_info)
 
     def reflink(self, from_info: AnyFSPath, to_info: AnyFSPath) -> None:
         try:
             return self.fs.reflink(from_info, to_info)
         except AttributeError:
-            raise RemoteActionNotImplemented("reflink", self.protocol)
+            raise LinkError("symlink", self, from_info)
 
     def is_symlink(self, path: AnyFSPath) -> bool:
         try:

dvc/objects/fs/generic.py

@@ -4,7 +4,6 @@ import os
 from typing import TYPE_CHECKING, List, Optional
 
 from ._callback import DEFAULT_CALLBACK
-from .base import RemoteActionNotImplemented
 from .implementations.local import LocalFileSystem
 from .utils import as_atomic
 
@@ -25,15 +24,8 @@ def _link(
     if not isinstance(from_fs, type(to_fs)):
         raise OSError(errno.EXDEV, "can't link across filesystems")
 
-    try:
-        func = getattr(to_fs, link)
-        func(from_path, to_path)
-    except (OSError, AttributeError, RemoteActionNotImplemented) as exc:
-        # NOTE: there are so many potential error codes that a link call can
-        # throw, that is safer to just catch them all and try another link.
-        raise OSError(
-            errno.ENOTSUP, f"'{link}' is not supported by {type(from_fs)}"
-        ) from exc
+    func = getattr(to_fs, link)
+    func(from_path, to_path)
 
 
 def copy(
@@ -75,7 +67,7 @@ def _try_links(
         try:
             return _link(link, from_fs, from_path, to_fs, to_path)
         except OSError as exc:
-            if exc.errno not in [errno.ENOTSUP, errno.EXDEV]:
+            if exc.errno not in [errno.EPERM, errno.ENOTSUP, errno.EXDEV]:
                 raise
             error = exc
 

dvc/output.py

@@ -893,7 +893,7 @@ class Output:
 
         try:
             self.get_dir_cache(jobs=jobs, remote=remote)
-        except RemoteMissingDepsError:
+        except RemoteMissingDepsError:  # pylint: disable=try-except-raise
             raise
         except DvcException:
             logger.debug(f"failed to pull cache for '{self}'")

tests/unit/cli/test_main.py

@@ -1,9 +1,11 @@
 from argparse import Namespace
 
+import pytest
 from funcy import raiser
 
 from dvc.cli import main
 from dvc.objects.cache import DiskError
+from dvc.objects.fs.base import FileSystem, RemoteMissingDepsError
 
 
 def test_state_pickle_errors_are_correctly_raised(tmp_dir, caplog, mocker):
@@ -24,3 +26,45 @@ def test_state_pickle_errors_are_correctly_raised(tmp_dir, caplog, mocker):
         "and then retry this command.\n"
         "See <https://error.dvc.org/pickle> for more information."
     ) in caplog.text
+
+
+@pytest.mark.parametrize(
+    "pkg, msg",
+    [
+        (None, "Please report this bug to"),
+        ("pip", "pip install 'dvc[proto]'"),
+        ("conda", "conda install -c conda-forge dvc-proto"),
+    ],
+)
+def test_remote_missing_deps_are_correctly_reported(
+    tmp_dir, caplog, mocker, pkg, msg
+):
+    error = RemoteMissingDepsError(FileSystem(), "proto", "proto://", ["deps"])
+    mocker.patch("dvc.utils.pkg.PKG", pkg)
+    mocker.patch(
+        "dvc.cli.parse_args",
+        return_value=Namespace(
+            func=raiser(error),
+            quiet=False,
+            verbose=True,
+        ),
+    )
+
+    assert main() == 255
+    expected = (
+        "URL 'proto://' is supported but requires these missing dependencies: "
+        "['deps']. "
+    )
+    if pkg:
+        expected += (
+            "To install dvc with those dependencies, run:\n\n"
+            f"\t{msg}\n\n"
+            "See <https://dvc.org/doc/install> for more info."
+        )
+    else:
+        expected += (
+            "\nPlease report this bug to "
+            "<https://github.com/iterative/dvc/issues>. "
+            "Thank you!"
+        )
+    assert expected in caplog.text

tests/unit/fs/test_base.py

@@ -3,17 +3,8 @@ import pytest
 from dvc.fs import FileSystem, RemoteMissingDepsError
 
 
-@pytest.mark.parametrize(
-    "pkg, msg",
-    [
-        (None, "Please report this bug to"),
-        ("pip", "pip install"),
-        ("conda", "conda install"),
-    ],
-)
-def test_missing_deps(pkg, msg, mocker):
+def test_missing_deps(mocker):
     requires = {"missing": "missing"}
     mocker.patch.object(FileSystem, "REQUIRES", requires)
-    mocker.patch("dvc.utils.pkg.PKG", pkg)
-    with pytest.raises(RemoteMissingDepsError, match=msg):
+    with pytest.raises(RemoteMissingDepsError, match="missing dependencies"):
         FileSystem()

tests/unit/output/test_output.py

@@ -115,7 +115,7 @@ def test_remote_missing_depenency_on_dir_pull(tmp_dir, scm, dvc, mocker):
 
     with mocker.patch(
         "dvc.data_cloud.DataCloud.get_remote_odb",
-        side_effect=RemoteMissingDepsError("remote missing"),
+        side_effect=RemoteMissingDepsError(dvc.fs, "azure", "azure://", []),
     ):
         with pytest.raises(RemoteMissingDepsError):
             dvc.pull()