[ShousenZHANG]

Summary

Refs #24645, following #45221.

Enable strict Pyrefly checking for the plugin model backwards-invocation and chunk-merger tests. Annotate the existing tests, use the model types exercised by the parameterized cases, and explicitly check that resolved token limits exist before reading their fields.

 tests/unit_tests/pyrefly.toml — project-excludes
- core/plugin/backwards_invocation/test_model.py
- core/plugin/utils/test_chunk_merger.py

Existing cases, assertions and dependency patches are preserved. The converter's empty-list input now has an explicit element type.

Evidence

• Pyrefly 1.4.0: 37 errors and seven warnings before, zero diagnostics after. Full unit-test, container-test and production type checks pass.
• Both target files reach 100% type coverage: model backwards invocation 8/24 → 24/24 typed symbols; chunk merger 0/20 → 20/20. Together they add 36 typed symbols.
• All 61 tests pass on main and this branch, with identical ordered test IDs. All 99 existing assertion predicates are unchanged; three non-null assertions make their existing precondition explicit.
• Full Ruff format/check, 78 import contracts, response-contract lint, generated billing-client verification and all eight CI guards pass. Guards compare against the merge base.

Production type checking uses the Tencent provider source path for the Windows worktree. Tests run through the local Windows wrapper for readline/libmagic.

Merge Danger

Reversible; scope is two test modules and their strict-check exclusions. With the existing fixtures and parameterized inputs, the tests keep their invocation, billing, MIME, conversion and chunk-integrity assertions. Production behavior is unchanged.

Screenshots

Before	After
N/A: test typing and check configuration	N/A

Checklist

• This change requires a documentation update, included: Dify Document
• I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• I've verified the change and added or updated tests where meaningful regression risk justifies coverage.
• I've updated the documentation accordingly.
• I ran make lint && make type-check (backend) and vp staged (frontend) to appease the lint gods

Backend commands were run individually on Windows; there are no frontend or documentation changes.

From Codex

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[github-actions]

Pyrefly Diff

base → PR

--- /tmp/pyrefly_base.txt	2026-11-01 04:54:31.546507941 +0000
+++ /tmp/pyrefly_pr.txt	2026-11-01 04:54:06.050435054 +0000
@@ -4140,20 +4140,6 @@
    --> tests/unit_tests/core/plugin/backwards_invocation/test_app.py:439:16
 ERROR Object of class `Account` has no attribute `app_id` [missing-attribute]
    --> tests/unit_tests/core/plugin/backwards_invocation/test_app.py:440:16
-ERROR Object of class `NoneType` has no attribute `context_tokens` [missing-attribute]
-   --> tests/unit_tests/core/plugin/backwards_invocation/test_model.py:408:12
-ERROR Object of class `NoneType` has no attribute `max_output_tokens` [missing-attribute]
-   --> tests/unit_tests/core/plugin/backwards_invocation/test_model.py:409:12
-ERROR Object of class `NoneType` has no attribute `output_parameter` [missing-attribute]
-   --> tests/unit_tests/core/plugin/backwards_invocation/test_model.py:410:12
-ERROR Object of class `NoneType` has no attribute `context_tokens` [missing-attribute]
-   --> tests/unit_tests/core/plugin/backwards_invocation/test_model.py:434:12
-ERROR Object of class `NoneType` has no attribute `max_output_tokens` [missing-attribute]
-   --> tests/unit_tests/core/plugin/backwards_invocation/test_model.py:435:12
-ERROR Object of class `NoneType` has no attribute `max_output_tokens` [missing-attribute]
-   --> tests/unit_tests/core/plugin/backwards_invocation/test_model.py:454:12
-ERROR Object of class `NoneType` has no attribute `output_parameter` [missing-attribute]
-   --> tests/unit_tests/core/plugin/backwards_invocation/test_model.py:455:12
 ERROR Argument `TestPluginDaemonEntities.test_credential_type_helpers._FakeCredential` is not assignable to parameter `self` with type `CredentialType` in function `core.plugin.entities.plugin_daemon.CredentialType.get_name` [bad-argument-type]
    --> tests/unit_tests/core/plugin/entities/test_plugin_daemon.py:313:40
 ERROR Argument `object` is not assignable to parameter `method` with type `str` in function `httpx._api.request` [bad-argument-type]

[github-actions]

Pyrefly Type Coverage

Metric	Base	PR	Delta
Type coverage	81.60%	81.64%	+0.03%
Strict coverage	81.25%	81.28%	+0.03%
Typed symbols	85,638	85,674	+36
Untyped symbols	19,389	19,353	-36
Modules	4396	4396	0

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.85%. Comparing base (170dbae) to head (f706481).

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #45230   +/-   ##
=======================================
  Coverage   89.85%   89.85%           
=======================================
  Files        6249     6249           
  Lines      398125   398125           
  Branches    80223    80223           
=======================================
+ Hits       357739   357744    +5     
+ Misses      34076    34070    -6     
- Partials     6310     6311    +1     

Flag	Coverage Δ
api	89.72% <ø> (+0.01%)	⬆️

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