forge: fix host-pinned REPO_ROOT in scan_dry verifier/probe — resolve from __file__

wizard-work/forge/HOST_PIN_PORTABILITY_FIX_VERIFICATION.md

@@ -0,0 +1,121 @@
+# Host-pin portability fix for _scan_dry refactor verifier (forge lane: Refactor)
+
+## The defect
+
+`verify_scan_dry_refactor.py` (committed at `d7e6e8e`) carried `REPO_ROOT = "/root/troupe-standup"`
+as a hard-coded literal at line 38. Its companion probe `_scan_dry_refactored.py` carried the same
+pattern at line 28: `REPO = "/root/troupe-standup"`.
+
+Volt's Q62 census graded both at `PASS*` (not `graded-clean`) because they hold a host-pin:
+a literal `/root/troupe-standup` that makes the verifier correct on this host and broken
+everywhere else. The control-plane record is explicit: `REPO = "/root/troupe-standup"` (`:42`)
+in `verify_scan_dry_refactor.py` is the one line the owning lane must change to leave the
+`PASS*` column.
+
+## The fix (two files)
+
+**verify_scan_dry_refactor.py** (lines 38-39, before):
+```python
+REPO_ROOT = "/root/troupe-standup"
+WORK_DIR = os.path.join(REPO_ROOT, "wizard-work", "forge")
+```
+
+After:
+```python
+# Resolve repo root from this file's location (wizard-work/forge/ -> repo root)
+# rather than hard-coding /root/troupe-standup. Eliminates the Q62 host-pin that
+# held this verifier in the PASS* column.
+WORK_DIR = os.path.dirname(os.path.abspath(__file__))
+REPO_ROOT = os.path.dirname(os.path.dirname(WORK_DIR))
+```
+
+**_scan_dry_refactored.py** (line 28, before):
+```python
+REPO = "/root/troupe-standup"
+```
+
+After:
+```python
+# Resolve repo root from this file's location (wizard-work/forge/ -> repo root)
+# rather than hard-coding /root/troupe-standup. Eliminates the host-pin.
+REPO = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+```
+
+The path arithmetic is correct:
+- File lives at `<repo>/wizard-work/forge/<file>.py`
+- `os.path.dirname(os.path.abspath(__file__))` = `<repo>/wizard-work/forge`
+- One more `dirname` = `<repo>/wizard-work`
+- One more = `<repo>` (the root)
+
+This matches the existing portable pattern in `verify_path_claim_apply_baseline_refactor.py`
+(`_HERE = os.path.dirname(os.path.abspath(__file__)` / `REPO = os.path.dirname(os.path.dirname(_HERE))`).
+
+## Evidence (measured, not claimed)
+
+### 1. No hard-coded literal remains as an executable assignment
+```
+$ grep -nE '^\s*(REPO_ROOT|REPO)\s*=\s*"/root/troupe-standup"' \
+    wizard-work/forge/verify_scan_dry_refactor.py \
+    wizard-work/forge/_scan_dry_refactored.py
+(no output -- rc 1, grep found no match)
+```
+The only remaining occurrences of `/root/troupe-standup` in both files are in comments
+explaining what was removed. The original `_scan_dry.py` still has `REPO = "/root/troupe-standup"`
+at line 6 — that is required: the non-vacuity guard (`check_original_still_smells`) asserts the
+original still carries the smells the refactor removed.
+
+### 2. The 11-check verifier passes after the fix
+```
+$ python3 wizard-work/forge/verify_scan_dry_refactor.py
+OK: py_compile passes
+OK: identical output (exit 0, 4811 bytes)
+OK: __main__ guard present
+OK: no 'global' statements in code
+OK: unused 'sys' import removed
+OK: redundant doubled 'or' clause removed; single 'len([ in l' present
+OK: bare open() replaced with 'with' context manager
+OK: scan_file, format_report, main extracted; main() calls scan_file
+OK: import is side-effect-free (no probe output at import)
+OK: scan_file real (/root/troupe-standup/tools/check_lint.py: 574 lines, 11 funcs); dup-body detection works
+OK: original still exhibits the removed smells (refactor is non-vacuous)
+
+=== Verification: 11/11 checks passed ===
+VERIFIER_EXIT=0
+```
+
+### 3. Portability: works from an unrelated working directory
+```
+$ cd /tmp && python3 /root/troupe-standup/wizard-work/forge/verify_scan_dry_refactor.py
+OK: scan_file real (/root/troupe-standup/tools/check_lint.py: 574 lines, 11 funcs); dup-body detection works
+OK: original still exhibits the removed smells (refactor is non-vacuous)
+
+=== Verification: 11/11 checks passed ===
+EXIT_FROM_TMP=0
+```
+The refactored probe also runs correctly from `/tmp` (rc 0), proving `REPO`/`TOOLS` resolve
+from `__file__` and not from cwd or a hard-coded root.
+
+### 4. AST-level confirmation: no executable string-literal assignment to REPO_ROOT/REPO
+```
+$ python3 _verify_portability_fix.py
+OK: REPO_ROOT='/root/troupe-standup' (resolved from __file__), SAMPLE_TOOL exists
+```
+The probe walks the AST of `verify_scan_dry_refactor.py` and asserts that no `Assign` node binds
+`REPO_ROOT` or `REPO` to the constant string `/root/troupe-standup`. It also confirms
+`REPO_ROOT` evaluates to the correct repo root and `SAMPLE_TOOL` exists on disk.
+
+## Non-tautology controls
+
+- The original `_scan_dry.py` was **not** modified: `REPO = "/root/troupe-standup"` survives
+  at line 6 so the non-vacuity guard has something to fail closed on. If the refactor had
+  deleted nothing, the original would have lost its smell and the guard would fire.
+- The byte-identical-output check (4811 bytes, cksum `2478253836`) confirms the path change
+  did not alter the scan's observable behavior — output is still byte-identical to the original.
+- Running from `/tmp` proves the path is resolved, not just correct on the native host.
+
+## Result
+
+Two hard-coded `/root/troupe-standup` literals removed. The verifier passes 11/11 from any
+working directory. The Q62 host-pin on this file is eliminated: `REPO_ROOT` and `REPO` now
+derive from `__file__`, following the same pattern already in use by
+`verify_path_claim_apply_baseline_refactor.py`.

wizard-work/forge/_scan_dry_refactored.py

@@ -25,7 +25,9 @@ import collections
 import hashlib
 import os
 
-REPO = "/root/troupe-standup"
+# Resolve repo root from this file's location (wizard-work/forge/ -> repo root)
+# rather than hard-coding /root/troupe-standup. Eliminates the host-pin.
+REPO = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 TOOLS = os.path.join(REPO, "tools")
 
 # Minimum repetition count for a line to be flagged as "repeated".

wizard-work/forge/verify_scan_dry_refactor.py

@@ -35,8 +35,11 @@ import subprocess
 import sys
 import tempfile
 
-REPO_ROOT = "/root/troupe-standup"
-WORK_DIR = os.path.join(REPO_ROOT, "wizard-work", "forge")
+# Resolve repo root from this file's location (wizard-work/forge/ -> repo root)
+# rather than hard-coding /root/troupe-standup. Eliminates the Q62 host-pin that
+# held this verifier in the PASS* column.
+WORK_DIR = os.path.dirname(os.path.abspath(__file__))
+REPO_ROOT = os.path.dirname(os.path.dirname(WORK_DIR))
 ORIGINAL = "_scan_dry.py"
 REFACTORED = "_scan_dry_refactored.py"
 MOD_NAME = REFACTORED[:-3]  # strip ".py"