feat: ground function-local import calls in DiffGraph

[nia-sg-bot]

Summary

• preserve the lexical scope of Python imports during deterministic Tree-sitter extraction
• emit import_grounded call edges for direct calls to names imported inside a function
• keep local imports scoped so sibling functions cannot inherit their bindings

Validation

• python3 -m pytest -q (178 passed)
• git diff --check

Part of #22

Summary by CodeRabbit

• Bug Fixes

  • Improved call analysis for imports defined inside functions, methods, and class bodies.
  • Function-local imports now resolve calls only within their enclosing scope, preventing incorrect matches in sibling functions.
  • Class-body imports resolve calls made directly in the class body without affecting nested method lookups.
  • Module-level import rebinding is handled more accurately.

• Tests

  • Added coverage for scope-specific import resolution, including class-body and nested method behavior.

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📥 Commits

Reviewing files that changed from the base of the PR and between 7d74788 and 6e8f523.

📒 Files selected for processing (2)

• diffgraph/structural.py
• tests/test_structural.py

🚧 Files skipped from review as they are similar to previous changes (2)

• tests/test_structural.py
• diffgraph/structural.py

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Walkthrough

Import records now retain their enclosing function scope. Call resolution uses scope-specific histories for function, module, and initial class-body calls. A regression test verifies distinct class-body and nested-method targets.

Changes

Lexical import resolution

Layer / File(s)	Summary
Scoped import history diffgraph/structural.py	_Import records its enclosing function scope. _imported_call_targets groups histories by scope, records same-scope rebindings, records module rebindings, and sorts histories by source line.
Scoped call resolution diffgraph/structural.py, tests/test_structural.py	_resolve_call_target resolves function-local, module-level, and initial class-body imports. Method lookups skip class namespaces. The regression test verifies separate class-body and nested-method targets.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Feature

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 62.50% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 8 functions across 2 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the main change: resolving function-local import calls in DiffGraph. It is concise and specific.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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Actionable comments posted: 1

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Inline comments:
In `@diffgraph/structural.py`:
- Around line 574-577: The _resolve_call_target lookup must include the initial
class-body scope so calls use imports recorded under the class qualified name,
while method callers must continue skipping class scopes during outward lookup.
Update the caller-scope traversal to distinguish an initial class-body caller
from a method caller, and add regression coverage for both class-body resolution
and nested-method resolution where an enclosing function imports the same name.

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ℹ️ Review info

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Configuration used: Organization UI

Review profile: CHILL

Plan: Advanced

Run ID: 0b37e1b4-a19d-497c-aef5-c003d243a8e9

📥 Commits

Reviewing files that changed from the base of the PR and between 1d09250 and 7d74788.

📒 Files selected for processing (2)

• diffgraph/structural.py
• tests/test_structural.py

Included review availability: Your plan provides up to 1 included review per hour; 0 remain after this review.

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