fix: avoid TypeError on CommaDelimitedList parameter / logical ID collision

[vishwakt]

Which issue(s) does this change fix?

Fixes #8627

Why is this change necessary?

sam deploy --guided (and any other command path that resolves a template) crashes with TypeError: unhashable type: 'list' when a CloudFormation template contains a CommaDelimitedList parameter whose name collides with a Resource or Output logical ID of the same name.

Minimal repro template (from the issue thread):

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31

Parameters:
  AppName:
    Type: CommaDelimitedList
    Default: "hello, world"

Resources:
  MyFunction:
    Type: AWS::Serverless::Function
    Properties:
      Runtime: python3.12
      Handler: index.handler
      InlineCode: |
        def handler(event, context):
            return "hi"

Outputs:
  AppName:
    Value: !Ref AppName

How does it address the issue?

In samcli/lib/intrinsic_resolver/intrinsic_property_resolver.py, resolve_attribute() was using get_translation(key) or key to derive the processed key for Resources/Outputs. For a CommaDelimitedList parameter, IntrinsicsSymbolTable.get_translation() deliberately returns a Python list (e.g. ["hello", "world"]). That list was then assigned as a dictionary key on the next line, which is what raised TypeError: unhashable type: 'list'.

The fix narrows the use of the translated key to the case it was actually designed for — string renames (e.g. RestApi.Deployment → RestApi via logical_id_translator) — and falls back to the original key when the translation is anything other than a string:

translated_key = self._symbol_resolver.get_translation(key)
processed_key = translated_key if isinstance(translated_key, str) else key

Refs from the existing test suite (TestIntrinsicAttribteResolution) verify the logical-ID renaming path still works, since those translations resolve to strings.

What side effects does this change have?

• No behavior change for templates without a name collision.
• No behavior change for legitimate logical-ID renaming via logical_id_translator, which always returns a string for that path.
• Templates that previously crashed now resolve normally: the Output/Resource key is preserved as-is, and !Ref <CommaDelimitedListParam> values continue to expand into a list as expected.

Mandatory Checklist

PRs will only be reviewed after checklist is complete

• Review the generative AI contribution guidelines
• Add input/output type hints to new functions/methods (no new functions added)
• Write design document if needed (Do I need to write a design document?) — not needed for a bug fix
• Write/update unit tests
• Write/update integration tests — bug is fully reproducible at the unit level
• Write/update functional tests if needed
• make pr passes
• make update-reproducible-reqs if dependencies were changed — no dependency changes
• Write documentation — no user-facing API change

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[vishwakt]

@reedham-aws Could you please re-trigger the workflow when you have a moment? Thanks for taking a look.

the CI failure was a black --check flagging one line in the new test

[roger-zhangg]

LGTM. The fix is minimal, correct, and well-tested.

Root cause confirmed: get_translation() in IntrinsicsSymbolTable returns a list when a CommaDelimitedList parameter name collides with a Resource/Output logical ID (line 347 of intrinsics_symbol_table.py). Using that list as a dict key in resolve_attribute() raised TypeError: unhashable type: 'list'.

Fix verified: The isinstance(translated_key, str) guard correctly filters out the list case while preserving the legitimate string-rename path. The three tests cover:

1. Output name collision (the reported bug)
2. Resource name collision (same code path, same class of issue)
3. String-based logical-ID renaming still works (no regression)

All 289 unit tests in test_intrinsic_resolver.py pass.

I've also rebased this branch onto develop to resolve the "behind" state.