fix(dspy): count only true assignments in ProgramOfThought._parse_code single-line guard

[detail-app]

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Detail bug report: View on Detail

📝 Changes Description

ProgramOfThought._parse_code rejected valid single-line Python that contains a comparison operator (==, !=, <=, >=). Its single-line guard used code_block.count("=") > 1, which counts every = character including those inside comparison operators, so a perfectly executable one-liner like result = 5 == 3 was rejected with ''"Error: Code format is not correct."'' before the interpreter was ever reached. If the LM regenerated the same shape across retries, forward wasted hops and could raise RuntimeError: Max hops reached.... The bug was reachable on the deprecated single-line "old-style" path (no SUBMIT()), where result = 5 > 3 ran but the semantically identical result = 5 == 3 did not — an inconsistency left in place by the recent single-line echo fix (fe75476c).

• Fix: Replace the raw character count with one that counts only true assignments. Normalize each augmented-assignment operator (//=, **=, <<=, >>=, +=, -=, *=, /=, %=, &=, |=, ^=, @=) to a single =, strip the comparison operators (==, !=, <=, >=), then count =. Comparisons now contribute zero and augmented assignments contribute one, so a single assignment containing comparisons is accepted, while genuine multi-assignment single-liners are still rejected.
• Guard value preserved: a = b = 5, a = 1; b = 2, x += 1; y -= 2, x <<= 1; y >>= 2, and invalid=python=code still raise the format error (the existing test_pot_code_parse_error still passes, now for the right reason).
• Added regression tests covering: single-line comparisons accepted with the correct output-capturing echo; single-line augmented assignments accepted; genuine multi-assignment single-liners still rejected; a Deno-free end-to-end test (via MockInterpreter) confirming the comparison code reaches the interpreter on the first hop; and a @pytest.mark.deno end-to-end test mirroring test_old_style_pot confirming the parsed code evaluates to False under the real Deno/Pyodide interpreter.

Closes Unknown issue

✅ Contributor Checklist

• Pre-Commit checks are passing (locally and remotely) — ruff check --fix-only --exit-non-zero-on-fix and ruff format --check both clean on the changed files.
• Title of your PR / MR corresponds to the required format — fix(dspy): ... matches (label)(dspy): message.
• Commit message follows required format {label}(dspy): {message} — fix(dspy): count only true assignments in ProgramOfThought._parse_code single-line guard.

⚠️ Warnings

• AI assistance disclosure (per CONTRIBUTING.md): This change was prepared with the assistance of Detail (Detail: Automatic Fixes). The bug was reproduced directly against _parse_code, the fix was reviewed and understood line-by-line, and all verification was run locally. The human author reviewed and is submitting this PR.
• ProgramOfThought is deprecated (emits DeprecationWarning, will be removed in 3.5 in favor of RLM), so this fix targets a legacy path; it keeps that path consistent with the single-line support rehabilitated in fe75476c.
• Testing performed: Non-deno tests/predict/test_program_of_thought.py (29 passed, 7 deno deselected); the broader tests/predict/ suite (264 passed, 6 skipped, 0 failed — no regressions); ruff lint and format clean. The new @pytest.mark.deno end-to-end test was executed against a real Deno/Pyodide interpreter (deno 2.9.5) and passed (7 passed under -m deno --deno), confirming the parsed comparison code evaluates to False and flows through generate_output.

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[greptile-apps]

Greptile Summary

This PR adjusts ProgramOfThought._parse_code so comparison operators do not count as assignments and adds regression coverage for comparisons, augmented assignments, retry behavior, and real-interpreter execution. The revised guard handles ordinary result = lhs == rhs expressions, but it also admits comparison-first statement sequences for which the output-capturing echo selects the wrong identifier.

Confidence Score: 4/5

The PR should not merge until newly accepted comparison-first single-line programs capture the actual assigned result rather than the comparison’s left operand.

The comparison stripping fixes the reported ordinary assignment form, but it broadens accepted input to a realistic valid statement sequence that can silently return the wrong value.

Files Needing Attention: dspy/predict/program_of_thought.py

Important Files Changed

Filename	Overview
dspy/predict/program_of_thought.py	Reworks single-line assignment counting, but newly accepted comparison-first statement sequences can produce the wrong captured output.
tests/predict/test_program_of_thought.py	Adds broad regression coverage for standard comparison and augmented-assignment forms, but omits comparison-before-assignment sequences.

_{Reviews (1): Last reviewed commit: "fix(dspy): count only true assignments i..." | Re-trigger Greptile}

[greptile-apps]

Comparison selects wrong output

Stripping comparisons before counting assignments newly allows a comparison-first statement such as True == False; result = 2. The existing echo regex then mistakes the first = in == for an assignment and appends True, so the interpreter returns True instead of the intended result value. Restrict the accepted single-line forms or identify the actual assignment before appending its output variable.

Knowledge Base Used: Prediction programs and agent workflows