cowork-bot: fix install/dispatch exception handling — bare except Exception no longer swallows typer.Exit (double error print on pip failure); OSError reported cleanly in install + dispatch; Ctrl-C exits 130; +3 regression tests (27 pass, ruff clean)

Author: cowork-bot

src/devforge/cli.py

@@ -102,16 +102,21 @@ def install(
     repo_url = "https://github.com/Coding-Dev-Tools/devforge-cli.git"
     pkg = f"git+{repo_url}[{extras}]"
     console.print(f"[yellow]Installing {pkg}...[/yellow]")
+    # Only catch OS-level failures here. A bare `except Exception` would also
+    # swallow the typer.Exit raised below (typer.Exit subclasses Exception),
+    # double-printing an error line ("Error: 1") after the failure message.
     try:
-        result = subprocess.run([sys.executable, "-m", "pip", "install", pkg], capture_output=True, text=True)
-        if result.returncode == 0:
-            console.print(f"[green]Successfully installed:[/green] {', '.join(targets)}")
-        else:
-            console.print(f"[red]Installation failed:[/red] {result.stderr[:500]}")
-            raise typer.Exit(code=1)
-    except Exception as e:
-        console.print(f"[red]Error: {e}[/red]")
+        result = subprocess.run(
+            [sys.executable, "-m", "pip", "install", pkg], capture_output=True, text=True
+        )
+    except OSError as e:
+        console.print(f"[red]Error running pip:[/red] {e}")
         raise typer.Exit(code=1) from e
+    if result.returncode == 0:
+        console.print(f"[green]Successfully installed:[/green] {', '.join(targets)}")
+    else:
+        console.print(f"[red]Installation failed:[/red] {result.stderr[:500]}")
+        raise typer.Exit(code=1)
 
 
 @app.command(name="versions")
@@ -188,11 +193,19 @@ def dispatch(ctx: typer.Context):
         # `--config file.yaml`) reach the underlying CLI instead of being
         # rejected by typer as "No such option".
         forwarded = list(ctx.args)
-        result = subprocess.run(
-            [sys.executable, "-m", module_name] + forwarded,
-            capture_output=True,
-            text=True,
-        )
+        try:
+            result = subprocess.run(
+                [sys.executable, "-m", module_name] + forwarded,
+                capture_output=True,
+                text=True,
+            )
+        except OSError as e:
+            console.print(f"[red]Error launching {tool_name}:[/red] {e}")
+            raise typer.Exit(code=1) from e
+        except KeyboardInterrupt:
+            # Forward Ctrl-C as a conventional 130 exit, not a raw traceback.
+            console.print("[yellow]Interrupted.[/yellow]")
+            sys.exit(130)
         if result.stdout:
             sys.stdout.write(result.stdout)
         if result.stderr:

tests/test_cli.py

@@ -208,3 +208,33 @@ def test_versions_reports_error(self, _mock):
         result = runner.invoke(app, ["versions", "guard"])
         assert result.exit_code == 0
         assert "error checking" in result.stdout
+
+
+class TestInstallErrorHandling:
+    @mock.patch("devforge.cli.subprocess.run")
+    def test_install_failure_no_double_error(self, mock_run):
+        """A failed pip install must print exactly one failure message.
+
+        Regression guard: the old `except Exception` also caught the
+        typer.Exit raised after 'Installation failed', printing a spurious
+        second line ('Error: 1').
+        """
+        mock_run.return_value = mock.MagicMock(returncode=1, stdout="", stderr="boom")
+        result = runner.invoke(app, ["install", "guard"])
+        assert result.exit_code == 1
+        assert "Installation failed" in result.stdout
+        assert "Error: 1" not in result.stdout
+
+    @mock.patch("devforge.cli.subprocess.run", side_effect=OSError("pip missing"))
+    def test_install_oserror_reported(self, mock_run):
+        result = runner.invoke(app, ["install", "guard"])
+        assert result.exit_code == 1
+        assert "Error running pip" in result.stdout
+
+    @mock.patch("devforge.cli._is_tool_installed", return_value=True)
+    @mock.patch("devforge.cli.subprocess.run", side_effect=OSError("python gone"))
+    def test_dispatch_oserror_reported(self, mock_run, _mock_installed):
+        """OSError from the tool subprocess gets a clear message, not a traceback."""
+        result = runner.invoke(app, ["guard"])
+        assert result.exit_code == 1
+        assert "Error launching guard" in result.stdout