sim_lib_lang_python/
fidelity.rs

1//! Frozen fidelity statement for the embedded Python profile.
2
3/// Independently reported fidelity dimensions; never a blanket compatibility claim.
4#[derive(Clone, Copy, Debug, Eq, PartialEq)]
5pub struct PythonFidelity {
6    /// Frozen syntax authority accepted by `codec/python`.
7    pub syntax: &'static str,
8    /// Stable representation produced by the codec.
9    pub lowering: &'static str,
10    /// Behavior executed without a compiler or foreign VM.
11    pub direct_evaluation: &'static str,
12    /// Object and control behavior composed from shared organs.
13    pub object_control: &'static str,
14    /// Library and import boundary.
15    pub module_library: &'static str,
16    /// Resource and authority boundary.
17    pub boundedness: &'static str,
18    /// Expected, deliberately unclaimed surface.
19    pub expected_gaps: &'static [&'static str],
20}
21
22/// One frozen differential or regression case.
23#[derive(Clone, Copy, Debug, Eq, PartialEq)]
24pub struct PythonEvidenceCase {
25    /// Stable case name.
26    pub name: &'static str,
27    /// Behavior dimension exercised by the case.
28    pub dimension: &'static str,
29    /// Python source supplied to the SIM codec.
30    pub source: &'static str,
31    /// Frozen observation or fail-closed outcome.
32    pub expected: &'static str,
33    /// Whether the expected value came from the frozen external oracle.
34    pub external_oracle: bool,
35}
36
37/// Exact external oracle used to freeze simple differential expectations.
38/// It is evidence only: never linked, spawned, imported, or used at runtime.
39pub const PYTHON_EXTERNAL_ORACLE: &str = "CPython 3.14.6 (offline expected-value oracle only)";
40
41/// Honest public fidelity statement for this profile.
42pub const PYTHON_FIDELITY: PythonFidelity = PythonFidelity {
43    syntax: "bounded lossless Python 3.14.6 concrete syntax; admission is not execution support",
44    lowering: "stable python/module, python/statement, and python/token expressions",
45    direct_evaluation: "bounded tree-walking scalar expressions and assignments over lowered forms",
46    object_control: "checked classes/descriptors, exceptions, generators, matching, and managed cycles through shared organs",
47    module_library: "matrix-listed core plus caller-supplied Dir imports; no pip, host path, or ambient standard library",
48    boundedness: "codec budgets, evaluator step limits, managed-heap limits, and explicit capabilities",
49    expected_gaps: &[
50        "not a CPython replacement",
51        "no bytecode, compiler IR, optimizer, or foreign VM",
52        "no asyncio event loop, pip, ambient IO, or host import search",
53        "syntax coverage does not imply direct-evaluation coverage",
54    ],
55};
56
57/// Frozen cases spanning the profile's claimed and refused behavior.
58pub const PYTHON_EVIDENCE_CASES: &[PythonEvidenceCase] = &[
59    PythonEvidenceCase {
60        name: "call",
61        dimension: "direct-evaluation",
62        source: "f = lambda x: x + 2\nf(40)\n",
63        expected: "42",
64        external_oracle: true,
65    },
66    PythonEvidenceCase {
67        name: "cyclic-value",
68        dimension: "object/control",
69        source: "value = []\nvalue.append(value)\nvalue is value[0]\n",
70        expected: "true; shared bounded heap",
71        external_oracle: true,
72    },
73    PythonEvidenceCase {
74        name: "exception",
75        dimension: "object/control",
76        source: "try:\n raise ValueError('x')\nexcept ValueError:\n answer = 42\n",
77        expected: "42",
78        external_oracle: true,
79    },
80    PythonEvidenceCase {
81        name: "generator",
82        dimension: "object/control",
83        source: "def g():\n yield 40\n yield 2\nsum(g())\n",
84        expected: "42",
85        external_oracle: true,
86    },
87    PythonEvidenceCase {
88        name: "matching",
89        dimension: "object/control",
90        source: "match [40, 2]:\n case [a, b]: answer = a + b\n",
91        expected: "42",
92        external_oracle: true,
93    },
94    PythonEvidenceCase {
95        name: "supplied-import",
96        dimension: "module/library",
97        source: "from supplied import answer\nanswer\n",
98        expected: "42 from caller-supplied Dir only",
99        external_oracle: false,
100    },
101    PythonEvidenceCase {
102        name: "ambient-import-refusal",
103        dimension: "module/library",
104        source: "import os\n",
105        expected: "refused without a supplied module root",
106        external_oracle: false,
107    },
108    PythonEvidenceCase {
109        name: "eval-capability-refusal",
110        dimension: "boundedness",
111        source: "eval('40 + 2')\n",
112        expected: "refused without read-eval and diminished capabilities",
113        external_oracle: false,
114    },
115    PythonEvidenceCase {
116        name: "exec-capability-refusal",
117        dimension: "boundedness",
118        source: "exec('answer = 42')\n",
119        expected: "refused without read-eval and diminished capabilities",
120        external_oracle: false,
121    },
122];
123
124#[cfg(test)]
125mod tests {
126    use super::*;
127    use std::{collections::BTreeSet, fs, path::Path};
128
129    #[test]
130    fn evidence_covers_every_required_regression_family() {
131        let names = PYTHON_EVIDENCE_CASES
132            .iter()
133            .map(|case| case.name)
134            .collect::<BTreeSet<_>>();
135        for required in [
136            "call",
137            "cyclic-value",
138            "exception",
139            "generator",
140            "matching",
141            "supplied-import",
142            "ambient-import-refusal",
143            "eval-capability-refusal",
144            "exec-capability-refusal",
145        ] {
146            assert!(
147                names.contains(required),
148                "missing Python evidence case {required}"
149            );
150        }
151        assert!(
152            PYTHON_EVIDENCE_CASES
153                .iter()
154                .any(|case| case.external_oracle)
155        );
156        assert!(
157            PYTHON_EVIDENCE_CASES
158                .iter()
159                .any(|case| !case.external_oracle)
160        );
161    }
162
163    #[test]
164    fn crate_has_no_foreign_python_or_compiler_dependency_or_artifact() {
165        let root = Path::new(env!("CARGO_MANIFEST_DIR"));
166        let manifest = fs::read_to_string(root.join("Cargo.toml"))
167            .unwrap()
168            .to_ascii_lowercase();
169        for forbidden in ["pyo3", "cpython =", "python3-sys", "python27-sys"] {
170            assert!(
171                !manifest.contains(forbidden),
172                "foreign Python dependency {forbidden}"
173            );
174        }
175        fn scan(path: &Path) {
176            for entry in fs::read_dir(path).unwrap() {
177                let path = entry.unwrap().path();
178                if path.is_dir() {
179                    scan(&path);
180                    continue;
181                }
182                let extension = path
183                    .extension()
184                    .and_then(|value| value.to_str())
185                    .unwrap_or("");
186                assert!(
187                    !matches!(extension, "pyc" | "pyo" | "pickle"),
188                    "foreign Python artifact {}",
189                    path.display()
190                );
191            }
192        }
193        scan(root);
194        let runtime = fs::read_to_string(root.join("src/runtime.rs")).unwrap();
195        for forbidden in [
196            "Py_CompileString",
197            "PyEval_",
198            "Command::new(\"python\"",
199            "Command::new(\"python3\"",
200        ] {
201            assert!(
202                !runtime.contains(forbidden),
203                "compiler/VM fallback marker {forbidden}"
204            );
205        }
206    }
207}
sim_lib_lang_python/fidelity.rs

sim_lib_lang_python/
fidelity.rs
