Usage of a != version specifier causes a parsing exception

[gforsyth]

What happened?

A recipe that uses a != comparison to filter a version causes an Exception:

EXCEPTION: An exception occurred while parsing the recipe file
while parsing a flow mapping
  in "<unicode string>", line 1, column 4
did not find expected ',' or '}'
  in "<unicode string>", line 1, column 24
0 errors and 0 warnings were found.

The diff below is a workaround for the same behavior:

@@ -79,7 +79,7 @@ outputs:
       string: cuda{{ cuda_major }}_{{ date_string }}_{{ GIT_DESCRIBE_HASH }}_{{ GIT_DESCRIBE_NUMBER }}
       ignore_run_exports_from:
         - {{ compiler('cuda') }}
-        - {{ "cuda-cudart-dev" if cuda_major != "11" else "cuda-version" }}
+        - {{ "cuda-cudart-dev" if not (cuda_major == "11") else "cuda-version" }}
     requirements:
       build:
         - cmake {{ cmake_version }}

To Reproduce

Steps to reproduce the behavior:

I've pasted a recipe below that has a != -- changing it as per the diff above allows the recipe converter to complete.

# Copyright (c) 2018-2025, NVIDIA CORPORATION.

{% set version = environ['RAPIDS_PACKAGE_VERSION'].lstrip('v') %}
{% set cuda_version = '.'.join(environ['RAPIDS_CUDA_VERSION'].split('.')[:2]) %}
{% set cuda_major = cuda_version.split('.')[0] %}
{% set date_string = environ['RAPIDS_DATE_STRING'] %}

package:
  name: librmm-split

source:
  path: ../../..

requirements:
  build:
    - cmake {{ cmake_version }}
    - ninja
    - {{ compiler('c') }}
    - {{ compiler('cxx') }}
    - {{ compiler('cuda') }} {{ cuda_version }} if cuda_major == "11" else compiler('cuda') }}
    - cuda-version ={{ cuda_version }}
    - {{ stdlib("c") }}
  host:
    - cuda-version ={{ cuda_version }}
    - fmt {{ fmt_version }}
    - spdlog {{ spdlog_version }}

build:
  script_env:
    - AWS_ACCESS_KEY_ID
    - AWS_SECRET_ACCESS_KEY
    - AWS_SESSION_TOKEN
    - CMAKE_C_COMPILER_LAUNCHER
    - CMAKE_CUDA_COMPILER_LAUNCHER
    - CMAKE_CXX_COMPILER_LAUNCHER
    - CMAKE_GENERATOR
    - PARALLEL_LEVEL
    - SCCACHE_BUCKET
    - SCCACHE_IDLE_TIMEOUT
    - SCCACHE_REGION
    - SCCACHE_S3_KEY_PREFIX=librmm-aarch64 # [aarch64]
    - SCCACHE_S3_KEY_PREFIX=librmm-linux64 # [linux64]
    - SCCACHE_S3_USE_SSL
    - SCCACHE_S3_NO_CREDENTIALS

outputs:
  - name: librmm
    version: {{ version }}
    script: install_librmm.sh
    build:
      number: {{ GIT_DESCRIBE_NUMBER }}
      string: cuda{{ cuda_major }}_{{ date_string }}_{{ GIT_DESCRIBE_HASH }}_{{ GIT_DESCRIBE_NUMBER }}
      run_exports:
        - {{ pin_subpackage("librmm", max_pin="x.x") }}
      ignore_run_exports_from:
        - {{ compiler('cuda') }}
    requirements:
      build:
        - cmake {{ cmake_version }}
      host:
        - cuda-version ={{ cuda_version }}
      run:
        - {{ pin_compatible('cuda-version', max_pin='x', min_pin='x') }}
        - {{ "cudatoolkit" if cuda_major == "11" else "cuda-version" }}
        - fmt {{ fmt_version }}
        - spdlog {{ spdlog_version }}
    test:
      commands:
        - test -d "${PREFIX}/include/rmm"
    about:
      home: https://rapids.ai/
      license: Apache-2.0
      summary: librmm library
  - name: librmm-tests
    version: {{ version }}
    script: install_librmm_tests.sh
    build:
      number: {{ GIT_DESCRIBE_NUMBER }}
      string: cuda{{ cuda_major }}_{{ date_string }}_{{ GIT_DESCRIBE_HASH }}_{{ GIT_DESCRIBE_NUMBER }}
      ignore_run_exports_from:
        - {{ compiler('cuda') }}
        - {{ "cuda-cudart-dev" if cuda_major != "11" else "cuda-version" }}
    requirements:
      build:
        - cmake {{ cmake_version }}
      host:
        - cuda-version ={{ cuda_version }}
        - {{ "cudatoolkit" if cuda_major == "11" else "cuda-cudart-dev" }}
      run:
        - {{ "cudatoolkit" if cuda_major == "11" else "cuda-cudart" }}
        - {{ pin_compatible('cuda-version', max_pin='x', min_pin='x') }}
        - {{ pin_subpackage('librmm', exact=True) }}
    about:
      home: https://rapids.ai/
      license: Apache-2.0
      summary: librmm test & benchmark executables

Additional Details (please complete the following information):

• OS: Linux, Ubuntu 24.04
• Conda Recipe Manager version: 0.4.1
• Any other context about the problem that was found.

[schuylermartin45]

Support for these in-line ternary statements is very new, so I'm glad you reported this. The ! likely breaks the nasty regex used to handle these ternary JINJA statements.

#285 Tracks full "support" for this logic by the parser, but I doubt we'll add it at this point.