bugfix: show-config command (#1846)

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## 📌 Description

I believe the show-config command line option was broken by #1794,
because it change the return type of `get_artifacts_status` from a list
of size 3 tuples to a tuple of size 2 tuples. This code in `__main__.py`
expects the former:

```
    status = get_artifacts_status()
    num_downloaded = sum(1 for _, _, exists in status if exists)
    total_cubins = len(status)
```

This PR has a fix and a test to protect against future breaks.

## 🔍 Related Issues

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## 🧪 Tests

- [x] Tests have been added or updated as needed.
- [x] All tests are passing (`unittest`, etc.).

## Reviewer Notes

Is this the right place to add CLI tests? Note that I've added a
`tests/cli` subdirectory.

Author: sricketts

flashinfer/__main__.py

@@ -114,7 +114,7 @@ def show_config_cmd():
     click.secho("=== Downloaded Cubins ===", fg="yellow")
 
     status = get_artifacts_status()
-    num_downloaded = sum(1 for _, _, exists in status if exists)
+    num_downloaded = sum(1 for _, exists in status if exists)
     total_cubins = len(status)
 
     click.secho(f"Downloaded {num_downloaded}/{total_cubins} cubins", fg="cyan")
@@ -137,10 +137,10 @@ def list_cubins_cmd():
     """List downloaded cubins"""
     status = get_artifacts_status()
     table_data = []
-    for name, extension, exists in status:
+    for file_name, exists in status:
         status_str = "Downloaded" if exists else "Missing"
         color = "green" if exists else "red"
-        table_data.append([f"{name}{extension}", click.style(status_str, fg=color)])
+        table_data.append([file_name, click.style(status_str, fg=color)])
 
     click.echo(tabulate(table_data, headers=["Cubin", "Status"], tablefmt="github"))
     click.secho("", fg="white")

tests/cli/test_cli_show_config.py

@@ -0,0 +1,16 @@
+from click.testing import CliRunner
+
+from flashinfer.__main__ import cli
+
+
+def test_show_config_cmd_smoke(monkeypatch):
+    runner = CliRunner()
+    result = runner.invoke(cli, ["show-config"])
+    assert result.exit_code == 0, result.output
+    out = result.output
+
+    # Basic sections present
+    assert "=== Torch Version Info ===" in out
+    assert "=== Environment Variables ===" in out
+    assert "=== Artifact Path ===" in out
+    assert "=== Downloaded Cubins ===" in out