[PATCH] selftests: tc-testing: fix list_categories() crash on list type

[PATCH] selftests: tc-testing: fix list_categories() crash on list type

[mr.navi8680]

From: Naveen Anandhan <mr.navi8680@gmail.com>

list_categories() builds a set directly from the 'category'
field of each test case. Since 'category' is a list,
set(map(...)) attempts to insert lists into a set, which
raises:

  TypeError: unhashable type: 'list'

Flatten category lists and collect unique category names
using set.update() instead.

Signed-off-by: Naveen Anandhan <mr.navi8680@gmail.com>
---
 tools/testing/selftests/tc-testing/tdc_helper.py | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/tc-testing/tdc_helper.py b/tools/testing/selftests/tc-testing/tdc_helper.py
index e06f03c0fb5d..adb52fe3acc1 100644
--- a/tools/testing/selftests/tc-testing/tdc_helper.py
+++ b/tools/testing/selftests/tc-testing/tdc_helper.py
@@ -38,10 +38,14 @@ def list_test_cases(testlist):
 
 
 def list_categories(testlist):
-    """ Show all categories that are present in a test case file. """
-    categories = set(map(lambda x: x['category'], testlist))
+    """Show all unique categories present in the test cases."""
+    categories = set()
+    for t in testlist:
+        if 'category' in t:
+            categories.update(t['category'])
+
     print("Available categories:")
-    print(", ".join(str(s) for s in categories))
+    print(", ".join(sorted(categories)))
     print("")
 
 
-- 
2.43.0

Re: [PATCH] selftests: tc-testing: fix list_categories() crash on list type

[Jakub Kicinski]

On Sat, 28 Feb 2026 13:17:35 +0530 mr.navi8680@gmail.com wrote:
> list_categories() builds a set directly from the 'category'
> field of each test case. Since 'category' is a list,
> set(map(...)) attempts to insert lists into a set, which
> raises:
> 
>   TypeError: unhashable type: 'list'
> 
> Flatten category lists and collect unique category names
> using set.update() instead.

How did you find this issue?

I can't figure out what's calling this function in the first place.
-- 
pw-bot: cr

Re: [PATCH] selftests: tc-testing: fix list_categories() crash on list type

[Naveen A]

> How did you find this issue? I can't figure out what's calling this
> function in the first place.

I encountered this while running the tc-testing selftests locally.

The script raised the error:

TypeError: unhashable type: 'list'

The traceback pointed to list_categories(), where a set(map(...))
was being created from the 'category' field.

Since 'category' is a list in the test cases, Python attempts to
insert the list itself into the set, which raises the unhashable
type error. After tracing this, I updated the logic to flatten the
category lists and collect unique category names using set.update().


On Wed, 4 Mar 2026 at 07:47, Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Sat, 28 Feb 2026 13:17:35 +0530 mr.navi8680@gmail.com wrote:
> > list_categories() builds a set directly from the 'category'
> > field of each test case. Since 'category' is a list,
> > set(map(...)) attempts to insert lists into a set, which
> > raises:
> >
> >   TypeError: unhashable type: 'list'
> >
> > Flatten category lists and collect unique category names
> > using set.update() instead.
>
> How did you find this issue?
>
> I can't figure out what's calling this function in the first place.
> --
> pw-bot: cr

Re: [PATCH] selftests: tc-testing: fix list_categories() crash on list type

[Jakub Kicinski]

On Wed, 4 Mar 2026 08:04:18 +0530 Naveen A wrote:
> > How did you find this issue? I can't figure out what's calling this
> > function in the first place.  
> 
> I encountered this while running the tc-testing selftests locally.

Running locally meaning? via tdc.py ? Or some other way ?

$ git grep list_categories
tools/testing/selftests/tc-testing/tdc_helper.py:def list_categories(testlist):

I guess I don't understand what the purpose if tdc_helper.py is
but the function you're polishing appears not to be called today..

Re: [PATCH] selftests: tc-testing: fix list_categories() crash on list type

[Naveen A]

You're right — after checking with git grep, it looks like
list_categories() is not currently called anywhere in the
tc-testing framework.

I originally noticed the issue while manually testing the helper
function in a small Python snippet, which triggered the error:

TypeError: unhashable type: 'list'

since the test definitions use a list for category, e.g.:

"category": ["filter", "fw"]

So the patch was intended to make the helper handle that format
correctly. But since the function appears unused today.

Thanks for pointing that out.

On Wed, 4 Mar 2026 at 08:19, Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Wed, 4 Mar 2026 08:04:18 +0530 Naveen A wrote:
> > > How did you find this issue? I can't figure out what's calling this
> > > function in the first place.
> >
> > I encountered this while running the tc-testing selftests locally.
>
> Running locally meaning? via tdc.py ? Or some other way ?
>
> $ git grep list_categories
> tools/testing/selftests/tc-testing/tdc_helper.py:def list_categories(testlist):
>
> I guess I don't understand what the purpose if tdc_helper.py is
> but the function you're polishing appears not to be called today..

Re: [PATCH] selftests: tc-testing: fix list_categories() crash on list type

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by David S. Miller <davem@davemloft.net>:

On Sat, 28 Feb 2026 13:17:35 +0530 you wrote:
> From: Naveen Anandhan <mr.navi8680@gmail.com>
> 
> list_categories() builds a set directly from the 'category'
> field of each test case. Since 'category' is a list,
> set(map(...)) attempts to insert lists into a set, which
> raises:
> 
> [...]

Here is the summary with links:
  - selftests: tc-testing: fix list_categories() crash on list type
    https://git.kernel.org/netdev/net/c/fbdfa8da05b6

You are awesome, thank you!
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