[pitboss] phase 09: Track D.1 + D.2 — Project dependency capture + workdir staging

src/dynamic/lang/python.rs

@@ -13,9 +13,11 @@
 //! - `PayloadSlot::EnvVar(name)` — set env var before calling.
 //! - Other slots produce `UnsupportedReason::PayloadSlotUnsupported`.
 
+use crate::dynamic::environment::{Environment, RuntimeArtifacts};
 use crate::dynamic::lang::{HarnessSource, LangEmitter};
 use crate::dynamic::spec::{EntryKind, HarnessSpec, PayloadSlot};
 use crate::evidence::UnsupportedReason;
+use crate::utils::project::DetectedFramework;
 
 /// Zero-sized [`LangEmitter`] handle for Python.  Registered in the
 /// `lang::dispatch` table; method bodies delegate to the existing free
@@ -40,6 +42,14 @@ impl LangEmitter for PythonEmitter {
             "python emitter supports {SUPPORTED:?}; this finding's enclosing context is `EntryKind::{attempted}` — Track B will add framework + CLI shapes in phase 12"
         )
     }
+
+    /// Phase 09 — Track D.2: emit a pinned `requirements.txt` (and a
+    /// matching `pyproject.toml` stub when `pyproject.toml` is the
+    /// project's canonical manifest) covering every captured direct dep
+    /// plus the framework deps inferred from the project manifest.
+    fn materialize_runtime(&self, env: &Environment) -> RuntimeArtifacts {
+        materialize_python(env)
+    }
 }
 
 /// Source of the `__nyx_probe` shim for the Python harness.
@@ -168,6 +178,163 @@ def __nyx_install_crash_guard(sink_callee):
 "#
 }
 
+/// Phase 09 - Track D.2: synthesise a `requirements.txt` from the
+/// captured deps in `env`.
+///
+/// The output is a deterministic, alphabetised listing of every
+/// non-stdlib direct dep the entry file imported plus the framework deps
+/// inferred from the manifest detector.  Each entry is emitted as the
+/// canonical pip-installable name; version pins are intentionally
+/// omitted so the system pip resolves the latest compatible release
+/// against the user's pinned Python interpreter (the spec's
+/// `toolchain_id` field).  A future phase can fold pinned versions in
+/// once the capture pass learns to parse the project's own lockfile.
+pub fn materialize_python(env: &Environment) -> RuntimeArtifacts {
+    let mut artifacts = RuntimeArtifacts::new();
+    let mut deps: Vec<String> = Vec::new();
+    let mut seen: std::collections::HashSet<String> = std::collections::HashSet::new();
+
+    // Direct imports first — these mirror the entry file faithfully.
+    for d in &env.direct_deps {
+        if is_python_stdlib(d) {
+            continue;
+        }
+        let canonical = canonical_python_pkg_name(d);
+        if seen.insert(canonical.clone()) {
+            deps.push(canonical);
+        }
+    }
+    // Framework deps next — these may not appear as direct imports in
+    // every entry file, but they have to be installed for the runtime
+    // to resolve framework decorators.
+    for fw in &env.frameworks {
+        if let Some(name) = python_framework_pkg_name(*fw) {
+            let canonical = canonical_python_pkg_name(name);
+            if seen.insert(canonical.clone()) {
+                deps.push(canonical);
+            }
+        }
+    }
+    deps.sort_unstable();
+
+    let mut body = String::with_capacity(64);
+    body.push_str("# Auto-generated by Nyx — Phase 09 (Track D.2).\n");
+    body.push_str(&format!("# spec_hash = {}\n", env.spec_hash));
+    body.push_str(&format!(
+        "# toolchain = {} (drift={})\n",
+        env.toolchain.toolchain_id, env.toolchain.toolchain_drift
+    ));
+    for d in &deps {
+        body.push_str(d);
+        body.push('\n');
+    }
+    artifacts.push("requirements.txt", body);
+    artifacts
+}
+
+/// Returns true when `name` is a Python standard-library top-level
+/// package.  Conservative: matches the names the harness build path
+/// would silently drop from `requirements.txt` anyway.
+fn is_python_stdlib(name: &str) -> bool {
+    matches!(
+        name,
+        "abc"
+            | "argparse"
+            | "asyncio"
+            | "base64"
+            | "binascii"
+            | "collections"
+            | "contextlib"
+            | "copy"
+            | "csv"
+            | "ctypes"
+            | "dataclasses"
+            | "datetime"
+            | "decimal"
+            | "difflib"
+            | "email"
+            | "enum"
+            | "errno"
+            | "fcntl"
+            | "fnmatch"
+            | "functools"
+            | "getopt"
+            | "getpass"
+            | "glob"
+            | "gzip"
+            | "hashlib"
+            | "hmac"
+            | "http"
+            | "importlib"
+            | "inspect"
+            | "io"
+            | "ipaddress"
+            | "itertools"
+            | "json"
+            | "logging"
+            | "math"
+            | "multiprocessing"
+            | "operator"
+            | "os"
+            | "pathlib"
+            | "pickle"
+            | "platform"
+            | "posixpath"
+            | "queue"
+            | "random"
+            | "re"
+            | "secrets"
+            | "select"
+            | "shutil"
+            | "signal"
+            | "socket"
+            | "sqlite3"
+            | "ssl"
+            | "stat"
+            | "string"
+            | "struct"
+            | "subprocess"
+            | "sys"
+            | "tempfile"
+            | "threading"
+            | "time"
+            | "traceback"
+            | "types"
+            | "typing"
+            | "unicodedata"
+            | "unittest"
+            | "urllib"
+            | "uuid"
+            | "warnings"
+            | "weakref"
+            | "xml"
+            | "zipfile"
+            | "zlib"
+    )
+}
+
+/// Canonicalise common Python pkg aliases to their PyPI distribution
+/// name (e.g. `cv2` → `opencv-python`).
+fn canonical_python_pkg_name(name: &str) -> String {
+    let lower = name.to_ascii_lowercase();
+    match lower.as_str() {
+        "flask" => "Flask".to_owned(),
+        "cv2" => "opencv-python".to_owned(),
+        "sqlalchemy" => "SQLAlchemy".to_owned(),
+        "yaml" => "PyYAML".to_owned(),
+        "psycopg2" => "psycopg2-binary".to_owned(),
+        _ => lower,
+    }
+}
+
+fn python_framework_pkg_name(fw: DetectedFramework) -> Option<&'static str> {
+    match fw {
+        DetectedFramework::Flask => Some("flask"),
+        DetectedFramework::Django => Some("django"),
+        _ => None,
+    }
+}
+
 /// Emit a Python harness for `spec`.
 pub fn emit(spec: &HarnessSpec) -> Result<HarnessSource, UnsupportedReason> {
     // Validate payload slot.