Improve error messages

spacy/cli/project.py

@@ -1,4 +1,4 @@
-from typing import List, Dict, Any, Optional
+from typing import List, Dict, Any, Optional, Sequence
 import typer
 import srsly
 from pathlib import Path
@@ -372,8 +372,7 @@ def print_run_help(project_dir: Path, subcommand: Optional[str] = None) -> None:
     config_commands = config.get("commands", [])
     commands = {cmd["name"]: cmd for cmd in config_commands}
     if subcommand:
-        if subcommand not in commands:
-            msg.fail(f"Can't find command '{subcommand}' in project config", exits=1)
+        validate_subcommand(commands.keys(), subcommand)
         print(f"Usage: {COMMAND} project run {project_dir} {subcommand}")
         help_text = commands[subcommand].get("help")
         if help_text:
@@ -401,8 +400,7 @@ def project_run(project_dir: Path, subcommand: str, *dvc_args) -> None:
     config_commands = config.get("commands", [])
     variables = config.get("variables", {})
     commands = {cmd["name"]: cmd for cmd in config_commands}
-    if subcommand not in commands:
-        msg.fail(f"Can't find command '{subcommand}' in project config", exits=1)
+    validate_subcommand(commands.keys(), subcommand)
     if subcommand in config.get("run", []):
         # This is one of the pipeline commands tracked in DVC
         dvc_cmd = ["dvc", "repro", subcommand, *dvc_args]
@@ -448,10 +446,14 @@ def load_project_config(path: Path) -> Dict[str, Any]:
     config_path = path / CONFIG_FILE
     if not config_path.exists():
         msg.fail("Can't find project config", config_path, exits=1)
-    config = srsly.read_yaml(config_path)
+    invalid_err = f"Invalid project config in {CONFIG_FILE}"
+    try:
+        config = srsly.read_yaml(config_path)
+    except ValueError as e:
+        msg.fail(invalid_err, e, exits=1)
     errors = validate(ProjectConfigSchema, config)
     if errors:
-        msg.fail(f"Invalid project config in {CONFIG_FILE}", "\n".join(errors), exits=1)
+        msg.fail(invalid_err, "\n".join(errors), exits=1)
     return config
 
 
@@ -490,8 +492,7 @@ def update_dvc_config(
     # commands in project.yml and should be run in sequence
     config_commands = {cmd["name"]: cmd for cmd in config.get("commands", [])}
     for name in config.get("run", []):
-        if name not in config_commands:
-            msg.fail(f"Can't find command '{name}' in project config", exits=1)
+        validate_subcommand(config_commands.keys(), name)
         command = config_commands[name]
         deps = command.get("deps", [])
         outputs = command.get("outputs", [])
@@ -634,6 +635,20 @@ def check_clone(name: str, dest: Path, repo: str) -> None:
         )
 
 
+def validate_subcommand(commands: Sequence[str], subcommand: str) -> None:
+    """Check that a subcommand is valid and defined. Raises an error otherwise.
+
+    commands (Sequence[str]): The available commands.
+    subcommand (str): The subcommand.
+    """
+    if subcommand not in commands:
+        msg.fail(
+            f"Can't find command '{subcommand}' in {CONFIG_FILE}. "
+            f"Available commands: {', '.join(commands)}",
+            exits=1,
+        )
+
+
 def download_file(url: str, dest: Path, chunk_size: int = 1024) -> None:
     """Download a file using requests.