Stabilize flaky Windows tests

[Bill Schnurr (bschnurr)]

Summary

• use the standard-library typing.ReadOnly in the diagnostic-category sample so it does not depend on an installed typing_extensions runtime file
• increase the MCP preflight Jest timeout to cover its 60-second internal timeout
• increase the nested harness process timeout to tolerate Windows runner contention

Validation

• pnpm run check:eslint
• pnpm run check:prettier
• 87 tests across typeEvaluator5.test.ts and mypyPrimerMcp.test.ts
• TypedDictReadOnly3 tests with Python removed from PATH
• five consecutive isolated runs of mypyPrimerMcp.test.ts

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

sympy (https://github.com/sympy/sympy)
+   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:176:44 - error: Cannot access attribute "expand" for class "Basic"
+     Attribute "expand" is unknown (reportAttributeAccessIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:423:38 - error: Argument of type "int | Expr" cannot be assigned to parameter "expr" of type "Expr" in function "make_args"
+   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:423:38 - error: Argument of type "Unknown | Expr | Literal[0]" cannot be assigned to parameter "expr" of type "Expr" in function "make_args"
-     Type "int | Expr" is not assignable to type "Expr"
+     Type "Unknown | Expr | Literal[0]" is not assignable to type "Expr"
-       "int" is not assignable to "Expr" (reportArgumentType)
+       "Literal[0]" is not assignable to "Expr" (reportArgumentType)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:504:19 - error: Operator "**" not supported for types "Unknown | Basic" and "Literal[2]"
-     Operator "**" not supported for types "Basic" and "Literal[2]" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:505:19 - error: Operator "*" not supported for types "Unknown | Basic" and "Unknown | Basic"
-     Operator "*" not supported for types "Basic" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:506:19 - error: Operator "**" not supported for types "Unknown | Basic" and "Literal[2]"
-     Operator "**" not supported for types "Basic" and "Literal[2]" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:569:42 - error: Operator "*" not supported for types "int" and "Unknown | Basic"
-     Operator "*" not supported for types "int" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:569:50 - error: Operator "*" not supported for types "Expr" and "Unknown | Basic"
-     Operator "*" not supported for types "Expr" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:725:42 - error: Operator "**" not supported for types "Unknown | Basic" and "Literal[2]"
-     Operator "**" not supported for types "Basic" and "Literal[2]" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:735:19 - error: Operator "**" not supported for types "Unknown | Basic" and "Literal[2]"
-     Operator "**" not supported for types "Basic" and "Literal[2]" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:736:19 - error: Operator "**" not supported for types "Unknown | Basic" and "Literal[2]"
-     Operator "**" not supported for types "Basic" and "Literal[2]" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:737:19 - error: Operator "**" not supported for types "Unknown | Basic" and "Literal[2]"
-     Operator "**" not supported for types "Basic" and "Literal[2]" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:814:47 - error: Operator "**" not supported for types "Unknown | Basic" and "Literal[2]"
-     Operator "**" not supported for types "Basic" and "Literal[2]" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:841:26 - error: Operator "**" not supported for types "Unknown | Basic" and "Literal[2]"
-     Operator "**" not supported for types "Basic" and "Literal[2]" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:842:22 - error: Operator "*" not supported for types "Unknown | Basic" and "Unknown | Basic"
-     Operator "*" not supported for types "Basic" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:843:36 - error: Operator "*" not supported for types "int" and "Unknown | Basic"
-     Operator "*" not supported for types "int" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:843:42 - error: Operator "*" not supported for types "Unknown | Basic" and "Unknown | Basic"
-     Operator "*" not supported for types "Basic" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:843:51 - error: Operator "*" not supported for types "int" and "Unknown | Basic"
-     Operator "*" not supported for types "int" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:843:57 - error: Operator "*" not supported for types "Unknown | Basic" and "Unknown | Basic"
-     Operator "*" not supported for types "Basic" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:843:66 - error: Operator "*" not supported for types "Unknown | Basic" and "Unknown | Basic"
-     Operator "*" not supported for types "Basic" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:845:53 - error: Operator "*" not supported for types "Unknown | Basic" and "Unknown | Basic"
-     Operator "*" not supported for types "Basic" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:854:18 - error: Operator "**" not supported for types "Unknown | Basic" and "Literal[2]"
-     Operator "**" not supported for types "Basic" and "Literal[2]" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:856:22 - error: Operator "**" not supported for types "Unknown | Basic" and "Literal[2]"
-     Operator "**" not supported for types "Basic" and "Literal[2]" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:865:22 - error: Operator "*" not supported for types "Unknown | Basic" and "Unknown | Basic"
-     Operator "*" not supported for types "Basic" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:865:36 - error: Operator "*" not supported for types "Unknown | Basic" and "Unknown | Basic"
-     Operator "*" not supported for types "Basic" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:867:27 - error: Operator "**" not supported for types "Unknown | Basic" and "Literal[2]"
-     Operator "**" not supported for types "Basic" and "Literal[2]" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:868:27 - error: Operator "*" not supported for types "Unknown | Basic" and "Unknown | Basic"
-     Operator "*" not supported for types "Basic" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:869:27 - error: Operator "*" not supported for types "Unknown | Basic" and "Unknown | Basic"
-     Operator "*" not supported for types "Basic" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:870:27 - error: Operator "**" not supported for types "Unknown | Basic" and "Literal[2]"
-     Operator "**" not supported for types "Basic" and "Literal[2]" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:871:27 - error: Operator "*" not supported for types "Unknown | Basic" and "Unknown | Basic"
-     Operator "*" not supported for types "Basic" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:872:27 - error: Operator "**" not supported for types "Unknown | Basic" and "Literal[2]"
-     Operator "**" not supported for types "Basic" and "Literal[2]" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:876:24 - error: Operator "**" not supported for types "Unknown | Basic" and "Literal[2]"
-     Operator "**" not supported for types "Basic" and "Literal[2]" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:877:24 - error: Operator "**" not supported for types "Unknown | Basic" and "Literal[2]"
-     Operator "**" not supported for types "Basic" and "Literal[2]" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:878:24 - error: Operator "**" not supported for types "Unknown | Basic" and "Literal[2]"
-     Operator "**" not supported for types "Basic" and "Literal[2]" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:879:24 - error: Operator "*" not supported for types "Unknown | Basic" and "Unknown | Basic"
-     Operator "*" not supported for types "Basic" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:880:24 - error: Operator "*" not supported for types "Unknown | Basic" and "Unknown | Basic"
-     Operator "*" not supported for types "Basic" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:881:24 - error: Operator "*" not supported for types "Unknown | Basic" and "Unknown | Basic"
-     Operator "*" not supported for types "Basic" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:888:37 - error: Operator "*" not supported for types "int" and "Unknown | None"
-     Operator "*" not supported for types "int" and "None" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:888:45 - error: Operator "*" not supported for types "int" and "Unknown | None"
-     Operator "*" not supported for types "int" and "None" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:891:24 - error: Operator "*" not supported for types "Unknown | Basic" and "Unknown | Basic"
-     Operator "*" not supported for types "Basic" and "Basic" (reportOperatorIssue)
-   .../projects/sympy/sympy/solvers/diophantine/diophantine.py:892:26 - error: Operator "**" not supported for types "Unknown | Basic" and "Literal[2]"

... (truncated 199 lines) ...

[github-actions]

mypy_primer analysis

Advisory AI analysis of primer run 36203302857, attempt 1
for commit 5690dcc283acbd9cd917fac4b480d01462e2528f. This is not an approval or proof of correctness.

Only SymPy changed. These differences are treated as non-blocking primer noise; no other project changed.

Recorded changes: 56 added / 94 removed diagnostic headers; 57 added / 73 removed detail lines.

Full evidence and limitations: download mypy-primer-analysis-report from this analysis run.
The original raw primer comment is unchanged. Treat uncertainty and possible regressions as requests for human review.