Repository: omni-us/jsonargparse

Issue:
Instantiation fails with TypeError only when fail_untyped=False
<!-- If you like this project, please ⭐ star it https://github.com/omni-us/jsonargparse/ -->

## 🐛 Bug report

I'm trying to instantiate a config class from Huggingface with CLI and it fails when `fail_untyped=False`. The fail_untyped is important because I'm doing this as part of a project that is written within the lightning framework, where we make heavy use of lightning cli, which sets fail_untyped to False and you can't change it. Most of our project is written internally by us and is not HuggingFace based, but we want to make use from time to time of some external models in the open source community (like for example HuggingFace). 

I created an isolated example just with jsonargparse (see below). It only fails when `fail_untyped=False` . I stepped through the instantiation and I'm quite confused of what's happening. `num_labels` is not set, and through kwargs.pop("num_labels", 2) it should become 2, which is an int.

```
File "/opt/pyenv/versions/3.10.12/lib/python3.10/site-packages/transformers/configuration_utils.py", line 331, in __init__
    self.num_labels = kwargs.pop("num_labels", 2)

File "/opt/pyenv/versions/3.10.12/lib/python3.10/site-packages/transformers/configuration_utils.py", line 256, in __setattr__
    super().__setattr__(key, value)

File "/opt/pyenv/versions/3.10.12/lib/python3.10/site-packages/transformers/configuration_utils.py", line 420, in num_labels
    self.id2label = {i: f"LABEL_{i}" for i in range(num_labels)}

TypeError: 'NoneType' object cannot be interpreted as an integer
```

As a side note I am planning to submit a PR soon to allow people to set fail_untyped in lightning https://github.com/Lightning-AI/lightning/issues/18285  . 

### To reproduce
```python
from jsonargparse import CLI
from dataclasses import dataclass
from transformers.models.perceiver.configuration_perceiver import PerceiverConfig


@dataclass
class Test:
    cfg: PerceiverConfig


print(CLI(Test, fail_untyped=False))
```

Config
```yaml
cfg:
  class_path: transformers.models.perceiver.configuration_perceiver.PerceiverConfig 
```

Command
```
python perceiver.py --config perceiver_config.yaml
``` 

### Expected behavior

No TypeError

### Environment

<!-- Fill in the list below. -->

- jsonargparse version:  4.23.1
- Python version: 3.10.12
- How jsonargparse was installed: `pip install jsonargparse[signatures,typing-extensions]==4.23.1`
- Huggingface transformers package: transformers==4.31.0
- OS: Ubuntu 22.04.2 LTS


Discussion:
sonarcloud[bot]: Kudos, SonarCloud Quality Gate passed!&nbsp; &nbsp; [![Quality Gate passed](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/QualityGateBadge/passed-16px.png 'Quality Gate passed')](https://sonarcloud.io/dashboard?id=omni-us_jsonargparse&pullRequest=364)

[![Bug](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/common/bug-16px.png 'Bug')](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=BUG) [![A](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/RatingBadge/A-16px.png 'A')](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=BUG) [0 Bugs](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=BUG)  
[![Vulnerability](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/common/vulnerability-16px.png 'Vulnerability')](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=VULNERABILITY) [![A](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/RatingBadge/A-16px.png 'A')](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=VULNERABILITY) [0 Vulnerabilities](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=VULNERABILITY)  
[![Security Hotspot](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/common/security_hotspot-16px.png 'Security Hotspot')](https://sonarcloud.io/project/security_hotspots?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=SECURITY_HOTSPOT) [![A](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/RatingBadge/A-16px.png 'A')](https://sonarcloud.io/project/security_hotspots?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=SECURITY_HOTSPOT) [0 Security Hotspots](https://sonarcloud.io/project/security_hotspots?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=SECURITY_HOTSPOT)  
[![Code Smell](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/common/code_smell-16px.png 'Code Smell')](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=CODE_SMELL) [![A](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/RatingBadge/A-16px.png 'A')](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=CODE_SMELL) [0 Code Smells](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=CODE_SMELL)

[![No Coverage information](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/CoverageChart/NoCoverageInfo-16px.png 'No Coverage information')](https://sonarcloud.io/component_measures?id=omni-us_jsonargparse&pullRequest=364) No Coverage information  
[![0.0%](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/Duplications/3-16px.png '0.0%')](https://sonarcloud.io/component_measures?id=omni-us_jsonargparse&pullRequest=364&metric=new_duplicated_lines_density&view=list) [0.0% Duplication](https://sonarcloud.io/component_measures?id=omni-us_jsonargparse&pullRequest=364&metric=new_duplicated_lines_density&view=list)


codecov[bot]: ## [Codecov](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364?src=pr&el=h1&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) Report
Patch coverage: **`100.00%`** and project coverage change: **`-0.04%`** :warning:
> Comparison is base [(`8356fdf`)](https://app.codecov.io/gh/omni-us/jsonargparse/commit/8356fdff453de4d044ba01d0119724481dcddc2b?el=desc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) 100.00% compared to head [(`27dfddd`)](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364?src=pr&el=desc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) 99.96%.

<details><summary>Additional details and impacted files</summary>


```diff
@@             Coverage Diff             @@
##              main     #364      +/-   ##
===========================================
- Coverage   100.00%   99.96%   -0.04%     
===========================================
  Files           21       21              
  Lines         5714     5714              
===========================================
- Hits          5714     5712       -2     
- Misses           0        2       +2     
```

| [Flag](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | Coverage Δ | |
|---|---|---|
| [py3.10](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | `?` | |
| [py3.10_all](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | `?` | |
| [py3.10_types](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | `?` | |
| [py3.11](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | `?` | |
| [py3.11_all](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | `?` | |
| [py3.11_types](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | `?` | |
| [py3.6](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | `85.06% <100.00%> (+0.07%)` | :arrow_up: |
| [py3.6_all](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | `96.64% <100.00%> (+0.01%)` | :arrow_up: |
| [py3.7](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | `88.15% <100.00%> (ø)` | |
| [py3.7_all](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | `99.52% <100.00%> (ø)` | |
| [py3.7_types](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | `99.50% <100.00%> (ø)` | |
| [py3.8](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | `88.32% <100.00%> (ø)` | |
| [py3.8_all](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | `99.59% <100.00%> (ø)` | |
| [py3.8_types](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | `99.57% <100.00%> (ø)` | |
| [py3.9](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | `?` | |
| [py3.9_all](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | `?` | |
| [py3.9_types](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | `?` | |

Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us#carryforward-flags-in-the-pull-request-comment) to find out more.

| [Files Changed](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us) | Coverage Δ | |
|---|---|---|
| [jsonargparse/\_parameter\_resolvers.py](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us#diff-anNvbmFyZ3BhcnNlL19wYXJhbWV0ZXJfcmVzb2x2ZXJzLnB5) | `100.00% <100.00%> (ø)` | |

... and [2 files with indirect coverage changes](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us)


</details>

[:umbrella: View full report in Codecov by Sentry](https://app.codecov.io/gh/omni-us/jsonargparse/pull/364?src=pr&el=continue&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us).   
:loudspeaker: Have feedback on the report? [Share it here](https://about.codecov.io/codecov-pr-comment-feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=omni-us).

sonarcloud[bot]: Kudos, SonarCloud Quality Gate passed!&nbsp; &nbsp; [![Quality Gate passed](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/QualityGateBadge/passed-16px.png 'Quality Gate passed')](https://sonarcloud.io/dashboard?id=omni-us_jsonargparse&pullRequest=364)

[![Bug](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/common/bug-16px.png 'Bug')](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=BUG) [![A](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/RatingBadge/A-16px.png 'A')](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=BUG) [0 Bugs](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=BUG)  
[![Vulnerability](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/common/vulnerability-16px.png 'Vulnerability')](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=VULNERABILITY) [![A](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/RatingBadge/A-16px.png 'A')](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=VULNERABILITY) [0 Vulnerabilities](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=VULNERABILITY)  
[![Security Hotspot](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/common/security_hotspot-16px.png 'Security Hotspot')](https://sonarcloud.io/project/security_hotspots?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=SECURITY_HOTSPOT) [![A](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/RatingBadge/A-16px.png 'A')](https://sonarcloud.io/project/security_hotspots?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=SECURITY_HOTSPOT) [0 Security Hotspots](https://sonarcloud.io/project/security_hotspots?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=SECURITY_HOTSPOT)  
[![Code Smell](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/common/code_smell-16px.png 'Code Smell')](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=CODE_SMELL) [![A](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/RatingBadge/A-16px.png 'A')](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=CODE_SMELL) [0 Code Smells](https://sonarcloud.io/project/issues?id=omni-us_jsonargparse&pullRequest=364&resolved=false&types=CODE_SMELL)

[![No Coverage information](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/CoverageChart/NoCoverageInfo-16px.png 'No Coverage information')](https://sonarcloud.io/component_measures?id=omni-us_jsonargparse&pullRequest=364) No Coverage information  
[![0.0%](https://sonarsource.github.io/sonarcloud-github-static-resources/v2/checks/Duplications/3-16px.png '0.0%')](https://sonarcloud.io/component_measures?id=omni-us_jsonargparse&pullRequest=364&metric=new_duplicated_lines_density&view=list) [0.0% Duplication](https://sonarcloud.io/component_measures?id=omni-us_jsonargparse&pullRequest=364&metric=new_duplicated_lines_density&view=list)



Patch:
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 73f7a38..db9cf3f 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -21,6 +21,9 @@ Fixed
   <https://github.com/omni-us/jsonargparse/issues/317>`__).
 - Dataclass nested in list not setting defaults (`#357
   <https://github.com/omni-us/jsonargparse/issues/357>`__)
+- AST resolver ``kwargs.pop()`` with conflicting defaults not setting the
+  conditional default (`#362
+  <https://github.com/omni-us/jsonargparse/issues/362>`__).
 
 
 v4.24.0 (2023-08-23)
diff --git a/DOCUMENTATION.rst b/DOCUMENTATION.rst
index 9d12594..f68a386 100644
--- a/DOCUMENTATION.rst
+++ b/DOCUMENTATION.rst
@@ -1693,11 +1693,11 @@ A special case which is supported but with caveats, is multiple calls that use
 
 The resolved parameters that have the same type hint and default across all
 calls are supported normally. When there is a discrepancy between the calls, the
-parameters behave differently and are shown in the help in special "Conditional
-arguments" sections. The main difference is that these arguments are not
-included in :py:meth:`.ArgumentParser.get_defaults` or the output of
-``--print_config``. This is necessary because the parser does not know which of
-the calls will be used at runtime, and adding them would cause
+parameters behave differently and are shown in the help with the default like
+``Conditional<ast-resolver> {DEFAULT_1, ...}``. The main difference is that
+these parameters are not included in :py:meth:`.ArgumentParser.get_defaults` or
+the output of ``--print_config``. This is necessary because the parser does not
+know which of the calls will be used at runtime, and adding them would cause
 :py:meth:`.ArgumentParser.instantiate_classes` to fail due to unexpected keyword
 arguments.
 
@@ -1747,6 +1747,10 @@ Without the stubs resolver, the
 given to the ``a`` and ``b`` arguments, instead of ``float``. And this means
 that the parser would not fail if given an invalid value, for instance a string.
 
+It is not possible to know the defaults of parameters discovered only because of
+the stubs. In these cases in the parser help the default is shown as
+``Unknown<stubs-resolver>`` and not included in
+:py:meth:`.ArgumentParser.get_defaults` or the output of ``--print_config``.
 
 .. _sub-classes:
 
diff --git a/jsonargparse/_parameter_resolvers.py b/jsonargparse/_parameter_resolvers.py
index c59ebe2..85a7c4c 100644
--- a/jsonargparse/_parameter_resolvers.py
+++ b/jsonargparse/_parameter_resolvers.py
@@ -40,8 +40,7 @@ ParamList = List[ParamData]
 parameter_attributes = [s[1:] for s in inspect.Parameter.__slots__]  # type: ignore
 kinds = inspect._ParameterKind
 ast_assign_type: Tuple[Type[ast.AST], ...] = (ast.AnnAssign, ast.Assign)
-param_kwargs_get = "**.get()"
-param_kwargs_pop = "**.pop()"
+param_kwargs_pop_or_get = "**.pop|get():"
 
 
 class SourceNotAvailable(Exception):
@@ -304,29 +303,6 @@ def add_stub_types(stubs: Optional[Dict[str, Any]], params: ParamList, component
 ast_literals = {ast.dump(ast.parse(v, mode="eval").body): partial(ast.literal_eval, v) for v in ["{}", "[]"]}
 
 
-def get_kwargs_pop_or_get_parameter(node, component, parent, doc_params, log_debug):
-    name = ast_get_constant_value(node.args[0])
-    if ast_is_constant(node.args[1]):
-        default = ast_get_constant_value(node.args[1])
-    else:
-        default = ast.dump(node.args[1])
-        if default in ast_literals:
-            default = ast_literals[default]()
-        else:
-            default = None
-            log_debug(f"unsupported kwargs pop/get default: {ast_str(node)}")
-    return ParamData(
-        name=name,
-        annotation=inspect._empty,
-        default=default,
-        kind=kinds.KEYWORD_ONLY,
-        doc=doc_params.get(name),
-        parent=parent,
-        component=component,
-        origin=param_kwargs_get if node.func.attr == "get" else param_kwargs_pop,
-    )
-
-
 def is_param_subclass_instance_default(param: ParamData) -> bool:
     if is_dataclass_like(type(param.default)):
         return False
@@ -368,31 +344,27 @@ def group_parameters(params_list: List[ParamList]) -> ParamList:
                 param.origin = None
         return params_list[0]
     grouped = []
-    params_count = 0
-    params_skip = set()
+    non_get_pop_count = 0
     params_dict = defaultdict(lambda: [])
     for params in params_list:
-        if params[0].origin not in {param_kwargs_get, param_kwargs_pop}:
-            params_count += 1
+        if not (params[0].origin or "").startswith(param_kwargs_pop_or_get):  # type: ignore
+            non_get_pop_count += 1
         for param in params:
-            if param.name not in params_skip and param.kind != kinds.POSITIONAL_ONLY:
+            if param.kind != kinds.POSITIONAL_ONLY:
                 params_dict[param.name].append(param)
-                if param.origin == param_kwargs_pop:
-                    params_skip.add(param.name)
     for params in params_dict.values():
         gparam = params[0]
         types = unique(p.annotation for p in params if p.annotation is not inspect._empty)
         defaults = unique(p.default for p in params if p.default is not inspect._empty)
-        if len(params) >= params_count and len(types) <= 1 and len(defaults) <= 1:
+        if len(params) >= non_get_pop_count and len(types) <= 1 and len(defaults) <= 1:
             gparam.origin = None
         else:
             gparam.parent = tuple(p.parent for p in params)
             gparam.component = tuple(p.component for p in params)
             gparam.origin = tuple(p.origin for p in params)
-            gparam.default = ConditionalDefault(
-                "ast-resolver",
-                (p.default for p in params) if len(defaults) > 1 else defaults,
-            )
+            if len(params) < non_get_pop_count:
+                defaults += ["NOT_ACCEPTED"]
+            gparam.default = ConditionalDefault("ast-resolver", defaults)
             if len(types) > 1:
                 gparam.annotation = Union[tuple(types)] if types else inspect._empty
         docs = [p.doc for p in params if p.doc]
@@ -644,6 +616,28 @@ class ParametersVisitor(LoggerProperty, ast.NodeVisitor):
         default_nodes = [d for n, d in enumerate(default_nodes) if arg_nodes[n].arg in param_names]
         return default_nodes
 
+    def get_kwargs_pop_or_get_parameter(self, node, component, parent, doc_params):
+        name = ast_get_constant_value(node.args[0])
+        if ast_is_constant(node.args[1]):
+            default = ast_get_constant_value(node.args[1])
+        else:
+            default = ast.dump(node.args[1])
+            if default in ast_literals:
+                default = ast_literals[default]()
+            else:
+                default = None
+                self.log_debug(f"unsupported kwargs pop/get default: {ast_str(node)}")
+        return ParamData(
+            name=name,
+            annotation=inspect._empty,
+            default=default,
+            kind=kinds.KEYWORD_ONLY,
+            doc=doc_params.get(name),
+            parent=parent,
+            component=component,
+            origin=param_kwargs_pop_or_get + self.get_node_origin(node),
+        )
+
     def get_parameters_args_and_kwargs(self) -> Tuple[ParamList, ParamList]:
         self.parse_source_tree()
         args_name = getattr(self.component_node.args.vararg, "arg", None)
@@ -664,9 +658,7 @@ class ParametersVisitor(LoggerProperty, ast.NodeVisitor):
         for node in [v for k, v in values_found if k == kwargs_name]:
             if isinstance(node, ast.Call):
                 if ast_is_kwargs_pop_or_get(node, kwargs_value_dump):
-                    param = get_kwargs_pop_or_get_parameter(
-                        node, self.component, self.parent, self.doc_params, self.log_debug
-                    )
+                    param = self.get_kwargs_pop_or_get_parameter(node, self.component, self.parent, self.doc_params)
                     params_list.append([param])
                     continue
                 kwarg = ast_get_call_kwarg_with_value(node, kwargs_value)
@@ -717,12 +709,15 @@ class ParametersVisitor(LoggerProperty, ast.NodeVisitor):
         self.log_debug(f"did not find use of {self.self_name}.{attr_name} in members of {self.parent}")
         return []
 
+    def get_node_origin(self, node) -> str:
+        return f"{get_parameter_origins(self.component, self.parent)}:{node.lineno}"
+
     def add_node_origins(self, params: ParamList, node) -> None:
         origin = None
         for param in params:
             if param.origin is None:
                 if not origin:
-                    origin = f"{get_parameter_origins(self.component, self.parent)}:{node.lineno}"
+                    origin = self.get_node_origin(node)
                 param.origin = origin
 
     def get_parameters_call_attr(self, attr_name: str, attr_value: ast.AST) -> Optional[ParamList]:


Test patch:
diff --git a/jsonargparse_tests/test_parameter_resolvers.py b/jsonargparse_tests/test_parameter_resolvers.py
index 0081fd5..03dcc3c 100644
--- a/jsonargparse_tests/test_parameter_resolvers.py
+++ b/jsonargparse_tests/test_parameter_resolvers.py
@@ -5,15 +5,15 @@ import inspect
 import xml.dom
 from calendar import Calendar
 from random import shuffle
-from typing import Any, Callable, Dict, List
+from typing import Any, Callable, Dict, List, Union
 from unittest.mock import patch
 
 import pytest
 
 from jsonargparse import Namespace, class_from_function
 from jsonargparse._optionals import docstring_parser_support
+from jsonargparse._parameter_resolvers import ConditionalDefault, is_lambda
 from jsonargparse._parameter_resolvers import get_signature_parameters as get_params
-from jsonargparse._parameter_resolvers import is_lambda
 from jsonargparse_tests.conftest import capture_logs, source_unavailable
 
 
@@ -383,6 +383,21 @@ def function_pop_get_from_kwargs(kn1: int = 0, **kw):
     kw.pop("pk1", "")
 
 
+def function_pop_get_conditional(p1: str, **kw):
+    """
+    Args:
+        p1: help for p1
+        p2: help for p2
+        p3: help for p3
+    """
+    kw.get("p3", "x")
+    if p1 == "a":
+        kw.pop("p2", None)
+    elif p1 == "b":
+        kw.pop("p2", 3)
+        kw.get("p3", "y")
+
+
 def function_with_bug(**kws):
     return does_not_exist(**kws)  # noqa: F821
 
@@ -451,6 +466,7 @@ def assert_params(params, expected, origins={}):
     assert expected == [p.name for p in params]
     docs = [f"help for {p.name}" for p in params] if docstring_parser_support else [None] * len(params)
     assert docs == [p.doc for p in params]
+    assert all(isinstance(params[n].default, ConditionalDefault) for n in origins.keys())
     param_origins = {
         n: [o.split(f"{__name__}.", 1)[1] for o in p.origin] for n, p in enumerate(params) if p.origin is not None
     }
@@ -502,8 +518,9 @@ def test_get_params_class_with_kwargs_in_dict_attribute():
 
 
 def test_get_params_class_kwargs_in_attr_method_conditioned_on_arg():
+    params = get_params(ClassG)
     assert_params(
-        get_params(ClassG),
+        params,
         ["func", "kmg1", "kmg2", "kmg3", "kmg4"],
         {
             2: ["ClassG._run:3", "ClassG._run:5"],
@@ -511,6 +528,10 @@ def test_get_params_class_kwargs_in_attr_method_conditioned_on_arg():
             4: ["ClassG._run:5"],
         },
     )
+    assert params[2].annotation == Union[str, float]
+    assert str(params[2].default) == "Conditional<ast-resolver> {-, 2.3}"
+    assert str(params[3].default) == "Conditional<ast-resolver> {True, False}"
+    assert str(params[4].default) == "Conditional<ast-resolver> {4, NOT_ACCEPTED}"
     with source_unavailable():
         assert_params(get_params(ClassG), ["func"])
 
@@ -645,12 +666,31 @@ def test_get_params_function_call_classmethod():
 def test_get_params_function_pop_get_from_kwargs(logger):
     with capture_logs(logger) as logs:
         params = get_params(function_pop_get_from_kwargs, logger=logger)
-    assert_params(params, ["kn1", "k2", "kn2", "kn3", "kn4", "pk1"])
+    assert str(params[1].default) == "Conditional<ast-resolver> {2, 1}"
+    assert_params(
+        params,
+        ["kn1", "k2", "kn2", "kn3", "kn4", "pk1"],
+        {1: ["function_pop_get_from_kwargs:10", "function_pop_get_from_kwargs:15"]},
+    )
     assert "unsupported kwargs pop/get default" in logs.getvalue()
     with source_unavailable():
         assert_params(get_params(function_pop_get_from_kwargs), ["kn1"])
 
 
+def test_get_params_function_pop_get_conditional():
+    params = get_params(function_pop_get_conditional)
+    assert str(params[1].default) == "Conditional<ast-resolver> {x, y}"
+    assert str(params[2].default) == "Conditional<ast-resolver> {None, 3}"
+    assert_params(
+        params,
+        ["p1", "p3", "p2"],
+        {
+            1: ["function_pop_get_conditional:8", "function_pop_get_conditional:13"],
+            2: ["function_pop_get_conditional:10", "function_pop_get_conditional:12"],
+        },
+    )
+
+
 def test_get_params_function_module_class():
     params = get_params(function_module_class)
     assert ["firstweekday"] == [p.name for p in params]
diff --git a/jsonargparse_tests/test_signatures.py b/jsonargparse_tests/test_signatures.py
index 5f0e0b9..22567a7 100644
--- a/jsonargparse_tests/test_signatures.py
+++ b/jsonargparse_tests/test_signatures.py
@@ -298,7 +298,7 @@ def test_add_class_conditional_kwargs(parser):
             "help for kmg1 (type: int, default: 1)",
             "help for kmg2 (type: Union[str, float], default: Conditional<ast-resolver> {-, 2.3})",
             "help for kmg3 (type: bool, default: Conditional<ast-resolver> {True, False})",
-            "help for kmg4 (type: int, default: Conditional<ast-resolver> 4)",
+            "help for kmg4 (type: int, default: Conditional<ast-resolver> {4, NOT_ACCEPTED})",
         ]
     for value in expected:
         assert value in help_str