fix: release EXISTS expression temporary

docs/CURRENT_STATUS.md

@@ -42,7 +42,7 @@ The `RUN COMMAND` path now decodes POSIX `pclose()` wait status before storing `
 
 `RUN COMMAND` is documented and validated as a trusted-code capability: it executes shell commands with the user's permissions and is not a sandbox. Claro does not claim untrusted-script safety or use a fragile blacklist sanitizer. Focused documentation coverage is `tools/validate_trusted_command_docs.py`.
 
-`GET ... KEY ... AS ...` now releases its temporary map and key values after lookup. `python3 tools/validate_get_key_expression_cleanup.py` reproduced 1,004,000 leaked bytes before the change and passes after it with ASan/UBSan/LSan enabled; this is one narrow expression-temporary cleanup slice, not a claim that all runtime allocations are leak-free.
+`GET ... KEY ... AS ...` now releases its temporary map and key values after lookup. `python3 tools/validate_get_key_expression_cleanup.py` reproduced 1,004,000 leaked bytes before the change and passes after it with ASan/UBSan/LSan enabled. `EXISTS FILE ... AS ...` now releases its evaluated path value after checking it; `python3 tools/validate_exists_expression_cleanup.py` first reproduced 62,000 leaked bytes across 2,000 calls, then passed with ASan/UBSan/LSan enabled. These are narrow expression-temporary cleanup slices, not a claim that all runtime allocations are leak-free. Verified 2026-09-26: `make -s all`, `./claro test` (0 failures), `./claro doctor`, `./claro validate`, the focused cleanup validator, and `git diff --check` pass.
 
 ## Feature matrix
 

src/claro.c

@@ -442,7 +442,7 @@ static void exec_line(Runtime *rt,Program *p,int *pcp,const char *raw){ char buf
  if(strcmp(up,"PUT")==0){ const char *key=find_word_ci(t,"KEY"), *val=find_word_ci(t,"VALUE"), *as=find_word_ci(t,"AS"), *into=find_word_ci(t,"INTO"); if(key&&val){ char *me=substr(t+3,key); char *ke=substr(key+3,val); char *ve=xstrdup(val+5); Value m=eval_expr(rt,me); Value k=eval_expr(rt,ke); Value v=eval_expr(rt,ve); char *ks=v_to_string(k); if(m.type==V_MAP){ char *mn=trim_inplace(me); map_put(m.map,ks,v); rt_set(rt,mn,m); } free(ks); free(me); free(ke); free(ve); value_free(m); value_free(k); value_free(v); } else if(as&&into){ char *ke=substr(t+3,as); char *ve=substr(as+2,into); char *mn=xstrdup(trim_inplace((char*)into+4)); Value m=rt_get(rt,mn); Value k=eval_expr(rt,ke); Value v=eval_expr(rt,ve); char *ks=v_to_string(k); if(m.type==V_MAP){ map_put(m.map,ks,v); rt_set(rt,mn,m); } free(ks); free(ke); free(ve); free(mn); } return; }
  if(strcmp(up,"WRITE")==0||strcmp(up,"APPEND")==0){ if(starts_ci(t+strlen(w)," FILE")){ const char *pcur=t+strlen(w)+5; const char *with=find_word_ci(pcur,"WITH"); if(with){ char *pe=substr(pcur,with); char *ve=xstrdup(with+4); Value pv=eval_expr(rt,pe); Value vv=eval_expr(rt,ve); char *path=v_to_string(pv), *text=v_to_string(vv); FILE *f=fopen(path,strcmp(up,"APPEND")==0?"ab":"wb"); if(!f) rt_error(rt,p->path,pc+1,"Could not write file: %s",strerror(errno)); else { fwrite(text,1,strlen(text),f); fclose(f);} free(path); free(text); free(pe); free(ve); } } return; }
  if(strcmp(up,"READ")==0){ const char *pcur=t+4; const char *as=find_word_ci(pcur,"AS"); if(as&&starts_ci(pcur," FILE")){ char *pe=substr(pcur+5,as); char *var=xstrdup(trim_inplace((char*)as+2)); Value pv=eval_expr(rt,pe); char *path=v_to_string(pv); FILE *f=fopen(path,"rb"); if(!f) rt_error(rt,p->path,pc+1,"Could not read file: %s",strerror(errno)); else { Str b; int c; str_init(&b); while((c=fgetc(f))!=EOF) str_ch(&b,(char)c); fclose(f); rt_set(rt,var,v_str(b.s?b.s:"")); free(b.s);} free(path); free(pe); free(var); } return; }
- if(strcmp(up,"EXISTS")==0){ const char *pcur=t+6; const char *as=find_word_ci(pcur,"AS"); if(as&&starts_ci(pcur," FILE")){ char *pe=substr(pcur+5,as); char *var=xstrdup(trim_inplace((char*)as+2)); Value pv=eval_expr(rt,pe); char *path=v_to_string(pv); rt_set(rt,var,v_bool(access(path,F_OK)==0)); free(path); free(pe); free(var);} return; }
+ if(strcmp(up,"EXISTS")==0){ const char *pcur=t+6; const char *as=find_word_ci(pcur,"AS"); if(as&&starts_ci(pcur," FILE")){ char *pe=substr(pcur+5,as); char *var=xstrdup(trim_inplace((char*)as+2)); Value pv=eval_expr(rt,pe); char *path=v_to_string(pv); rt_set(rt,var,v_bool(access(path,F_OK)==0)); free(path); value_free(pv); free(pe); free(var);} return; }
  if(strcmp(up,"CREATE")==0){ const char *pcur=t+6; if(starts_ci(pcur," FOLDER")){ char *pe=xstrdup(pcur+7); Value pv=eval_expr(rt,pe); char *path=v_to_string(pv); if(!make_folder(path)) rt_error(rt,p->path,pc+1,"Could not create folder: %s",strerror(errno)); free(path); free(pe); } return; }
  if(strcmp(up,"COPY")==0){ const char *to=find_word_ci(t,"TO"); if(starts_ci(t+4," FILE")&&to){ char *se=substr(t+9,to); char *de=xstrdup(to+2); Value sv=eval_expr(rt,se), dv=eval_expr(rt,de); char *src=v_to_string(sv), *dst=v_to_string(dv); if(!copy_file_bytes(src,dst)) rt_error(rt,p->path,pc+1,"Could not copy file"); free(src); free(dst); free(se); free(de); } return; }
  if(strcmp(up,"MOVE")==0){ const char *to=find_word_ci(t,"TO"); if(starts_ci(t+4," FILE")&&to){ char *se=substr(t+9,to); char *de=xstrdup(to+2); Value sv=eval_expr(rt,se), dv=eval_expr(rt,de); char *src=v_to_string(sv), *dst=v_to_string(dv); if(rename(src,dst)!=0) rt_error(rt,p->path,pc+1,"Could not move file: %s",strerror(errno)); free(src); free(dst); free(se); free(de); } return; }

tools/validate_exists_expression_cleanup.py

@@ -0,0 +1,51 @@
+#!/usr/bin/env python3
+"""Regression check for EXISTS FILE expression temporary ownership."""
+from pathlib import Path
+import os
+import subprocess
+import tempfile
+
+ROOT = Path(__file__).resolve().parent.parent
+
+
+def main() -> int:
+    if os.name == "nt":
+        print("SKIP: LeakSanitizer check is POSIX-only")
+        return 0
+    with tempfile.TemporaryDirectory(prefix="claro-exists-cleanup-") as tmp:
+        tmp_path = Path(tmp)
+        binary = tmp_path / "claro-lsan"
+        script = tmp_path / "exists_expressions.claro"
+        script.write_text(
+            'SET path TO "missing-file-for-cleanup-probe"\n'
+            + 'EXISTS FILE path AS present\n' * 2000
+            + "SAY present\n",
+            encoding="utf-8",
+        )
+        build = subprocess.run(
+            ["gcc", "-std=c99", "-O0", "-g", "-fsanitize=address,undefined",
+             "src/claro.c", "-o", str(binary), "-lm"],
+            cwd=ROOT, text=True, capture_output=True,
+        )
+        if build.returncode:
+            print(build.stdout, end="")
+            print(build.stderr, end="")
+            return build.returncode
+        run = subprocess.run(
+            [str(binary), str(script)], cwd=ROOT, text=True, capture_output=True,
+            env={**os.environ, "ASAN_OPTIONS": "detect_leaks=1"},
+        )
+        if run.returncode or "LeakSanitizer" in run.stderr or "SUMMARY:" in run.stderr:
+            print("FAIL: EXISTS FILE expression values still leak")
+            print(run.stdout, end="")
+            print(run.stderr, end="")
+            return 1
+        if run.stdout != "NO\n":
+            print(f"FAIL: unexpected EXISTS FILE probe output: {run.stdout!r}")
+            return 1
+        print("PASS: EXISTS FILE expression values are released")
+        return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())