Add exit codes that indicate what went wrong.

sno/branch.py

@@ -5,6 +5,7 @@
 import pygit2
 
 from .cli_util import do_json_option
+from .exceptions import InvalidOperation
 from .exec import execvp
 
 
@@ -33,7 +34,7 @@ def branch(ctx, do_json, args):
     if sargs & {"-d", "--delete", "-D"}:
         branch = repo.head.shorthand
         if branch in sargs:
-            raise click.ClickException(
+            raise InvalidOperation(
                 f"Cannot delete the branch '{branch}' which you are currently on."
             )
 

sno/checkout.py

@@ -4,6 +4,7 @@
 import click
 import pygit2
 
+from .exceptions import InvalidOperation, NotFound, NO_WORKING_COPY
 from .structure import RepositoryStructure
 from .working_copy import WorkingCopy
 
@@ -66,7 +67,7 @@ def checkout(ctx, branch, fmt, force, path, datasets, refish):
     wc = repo_structure.working_copy
     if wc:
         if path is not None:
-            raise click.ClickException(
+            raise InvalidOperation(
                 f"This repository already has a working copy at: {wc.path}",
             )
 
@@ -221,7 +222,7 @@ def restore(ctx, source, pathspec):
     repo_structure = RepositoryStructure(repo)
     working_copy = repo_structure.working_copy
     if not working_copy:
-        raise click.ClickException("You don't have a working copy")
+        raise NotFound("You don't have a working copy", exit_code=NO_WORKING_COPY)
 
     head_commit = repo.head.peel(pygit2.Commit)
 
@@ -246,7 +247,7 @@ def workingcopy_set_path(ctx, new):
 
     repo_cfg = repo.config
     if "sno.workingcopy.path" not in repo_cfg:
-        raise click.ClickException("No working copy? Try `sno checkout`")
+        raise NotFound("No working copy? Try `sno checkout`", exit_code=NO_WORKING_COPY)
 
     new = Path(new)
     # TODO: This doesn't seem to do anything?

sno/cli.py

@@ -13,6 +13,7 @@
     clone,
     commit,
     diff,
+    exceptions,
     init,
     fsck,
     merge,
@@ -25,6 +26,9 @@
 from .exec import execvp
 
 
+click.exceptions.UsageError.exit_code = exceptions.INVALID_ARGUMENT
+
+
 def print_version(ctx, param, value):
     if not value or ctx.resilient_parsing:
         return

sno/commit.py

@@ -13,6 +13,7 @@
 from . import is_windows
 from .core import check_git_user
 from .diff import Diff
+from .exceptions import NotFound, SubprocessError, NO_CHANGES, NO_DATA, NO_WORKING_COPY
 from .status import (
     get_branch_status_message,
     get_diff_status_message,
@@ -64,8 +65,9 @@ def commit(ctx, message, message_file, allow_empty, do_json):
     repo = ctx.obj.repo
 
     if repo.is_empty:
-        raise click.UsageError(
-            'Empty repository.\n  (use "sno import" to add some data)'
+        raise NotFound(
+            'Empty repository.\n  (use "sno import" to add some data)',
+            exit_code=NO_DATA,
         )
 
     check_git_user(repo)
@@ -75,7 +77,7 @@ def commit(ctx, message, message_file, allow_empty, do_json):
 
     working_copy = WorkingCopy.open(repo)
     if not working_copy:
-        raise click.UsageError("No working copy, use 'checkout'")
+        raise NotFound("No working copy, use 'checkout'", exit_code=NO_WORKING_COPY)
 
     working_copy.assert_db_tree_match(tree)
 
@@ -88,7 +90,7 @@ def commit(ctx, message, message_file, allow_empty, do_json):
         wc_changes[dataset.path] = diff.counts(dataset)
 
     if not wcdiff and not allow_empty:
-        raise click.ClickException("No changes to commit")
+        raise NotFound("No changes to commit", exit_code=NO_CHANGES)
 
     if message_file:
         commit_msg = message_file.read().strip()
@@ -98,7 +100,7 @@ def commit(ctx, message, message_file, allow_empty, do_json):
         commit_msg = get_commit_message(repo, wc_changes, quiet=do_json)
 
     if not commit_msg:
-        raise click.Abort()
+        raise click.UsageError("No commit message")
 
     rs.commit(wcdiff, commit_msg, allow_empty=allow_empty)
 
@@ -152,7 +154,7 @@ def get_commit_message(repo, wc_changes, quiet=False):
     try:
         subprocess.check_call(editor_cmd, shell=True)
     except subprocess.CalledProcessError as e:
-        raise click.ClickException(
+        raise SubprocessError(
             f"There was a problem with the editor '{editor}': {e}"
         ) from e
 

sno/context.py

@@ -1,8 +1,9 @@
 from pathlib import Path
 
-import click
 import pygit2
 
+from .exceptions import NotFound, NO_REPOSITORY
+
 
 class Context(object):
     DEFAULT_REPO_PATH = Path()
@@ -41,11 +42,12 @@ def repo(self):
 
         if not self._repo or not self._repo.is_bare:
             if self.has_repo_path:
-                raise click.BadParameter(
-                    "Not an existing repository", param_hint="--repo"
-                )
+                message = "Not an existing repository"
+                param_hint = "repo"
             else:
-                raise click.UsageError(
-                    "Current directory is not an existing repository"
-                )
+                message = "Current directory is not an existing repository"
+                param_hint = None
+
+            raise NotFound(message, exit_code=NO_REPOSITORY, param_hint=param_hint)
+
         return self._repo

sno/core.py

@@ -1,7 +1,5 @@
-import os
-
 import pygit2
-from click import ClickException
+from .exceptions import NotFound, NO_USER
 
 
 def walk_tree(top, path="", topdown=True):
@@ -99,4 +97,4 @@ def check_git_user(repo=None):
 
     msg.append("\n(sno uses the same credentials and configuration as git)")
 
-    raise ClickException("\n".join(msg))
+    raise NotFound("\n".join(msg), exit_code=NO_USER)

sno/diff.py

@@ -15,6 +15,13 @@
 
 from . import gpkg
 from .cli_util import MutexOption
+from .exceptions import (
+    InvalidOperation,
+    NotYetImplemented,
+    NotFound,
+    NO_WORKING_COPY,
+    UNCATEGORIZED_ERROR,
+)
 
 
 L = logging.getLogger("sno.diff")
@@ -456,7 +463,9 @@ def diff(ctx, output_format, output_path, exit_code, args):
             L.debug("commit_target=working-copy")
             working_copy = WorkingCopy.open(repo)
             if not working_copy:
-                raise click.UsageError("No working copy, use 'checkout'")
+                raise NotFound(
+                    "No working copy, use 'checkout'", exit_code=NO_WORKING_COPY
+                )
 
             working_copy.assert_db_tree_match(commit_head.peel(pygit2.Tree))
 
@@ -469,12 +478,12 @@ def diff(ctx, output_format, output_path, exit_code, args):
 
         if not merge_base:
             # there is no relation between the commits
-            raise click.ClickException(
+            raise InvalidOperation(
                 f"Commits {commit_base.id} and {c_target.id} aren't related."
             )
         elif merge_base not in (commit_base.id, c_target.id):
             # this needs a 3-way diff and we don't support them yet
-            raise click.ClickException(f"Sorry, 3-way diffs aren't supported yet.")
+            raise NotYetImplemented(f"Sorry, 3-way diffs aren't supported yet.")
 
         base_rs = RepositoryStructure(repo, commit_base)
         all_datasets = {ds.path for ds in base_rs}
@@ -519,35 +528,35 @@ def diff(ctx, output_format, output_path, exit_code, args):
                     diff_cc = base_ds.diff(
                         target_ds, pk_filter=(paths.get(dataset_path) or None), **params
                     )
-                    L.debug("commit<>commit diff (%s): %s", dataset.path, repr(diff_cc))
+                    L.debug("commit<>commit diff (%s): %s", dataset_path, repr(diff_cc))
                     diff += diff_cc
 
                 if commit_target is None:
                     # diff against working copy
                     target_ds = target_rs.get(dataset_path)
                     diff_wc = working_copy.diff_db_to_tree(
-                        target_ds, pk_filter=(paths.get(dataset.path) or None)
+                        target_ds, pk_filter=(paths.get(dataset_path) or None)
                     )
                     L.debug(
                         "commit<>working_copy diff (%s): %s",
-                        dataset.path,
+                        dataset_path,
                         repr(diff_wc),
                     )
                     diff += diff_wc
 
                 num_changes += len(diff)
-                L.debug("overall diff (%s): %s", dataset.path, repr(diff))
+                L.debug("overall diff (%s): %s", dataset_path, repr(diff))
                 w(dataset, diff[dataset])
     except click.ClickException as e:
         L.debug("Caught ClickException: %s", e)
-        if exit_code:
-            e.exit_code = 2
+        if exit_code and e.exit_code == 1:
+            e.exit_code = UNCATEGORIZED_ERROR
         raise
     except Exception as e:
         L.debug("Caught non-ClickException: %s", e)
         if exit_code:
             click.secho(f"Error: {e}", fg="red", file=sys.stderr)
-            raise SystemExit(2) from e
+            raise SystemExit(UNCATEGORIZED_ERROR) from e
         else:
             raise
     else:

sno/exceptions.py

@@ -0,0 +1,69 @@
+import click
+
+# Exit codes
+INVALID_ARGUMENT = 10
+
+INVALID_OPERATION = 20
+
+NOT_YET_IMPLEMENTED = 30
+
+NOT_FOUND = 40
+NO_REPOSITORY = 41
+NO_DATA = 42
+NO_BRANCH = 43
+NO_CHANGES = 44
+NO_WORKING_COPY = 45
+NO_USER = 46
+NO_IMPORT_SOURCE = 47
+NO_TABLE = 48
+
+SUBPROCESS_ERROR = 50
+
+UNCATEGORIZED_ERROR = 99
+
+
+class BaseException(click.ClickException):
+    """
+    A ClickException that can easily be constructed with any exit code,
+    and which can also optionally give a hint about which param lead to
+    the problem.
+    Providing a param hint or not can be done for any type of error -
+    an unparseable import path and an import path that points to a
+    corrupted database might both provide the same hint, but be
+    considered completely different types of errors.
+    """
+
+    exit_code = UNCATEGORIZED_ERROR
+
+    def __init__(self, message, exit_code=None, param=None, param_hint=None):
+        super(BaseException, self).__init__(message)
+
+        if exit_code is not None:
+            self.exit_code = exit_code
+
+        self.param_hint = None
+        if param_hint is not None:
+            self.param_hint = param_hint
+        elif param is not None:
+            self.param_hint = param.get_error_hint(None)
+
+    def format_message(self):
+        if self.param_hint is not None:
+            return f"Invalid value for {self.param_hint}: {self.message}"
+        return self.message
+
+
+class InvalidOperation(BaseException):
+    exit_code = INVALID_OPERATION
+
+
+class NotYetImplemented(BaseException):
+    exit_code = NOT_YET_IMPLEMENTED
+
+
+class NotFound(BaseException):
+    exit_code = NOT_FOUND
+
+
+class SubprocessError(BaseException):
+    exit_code = SUBPROCESS_ERROR