ww/test/wcc/821_def_str_index_reject.c

/*
 * 821_def_str_index_reject — indexing a bare DEF-GLOBAL scalar str is INVALID
 * ww and BOTH stages must LOUDLY REJECT at check time (#14, the #8 sibling;
 * drew ruling .ai/drew-14-ruling.md, rob spec .ai/rob-14-spec.md).
 *
 * `str[i] -> u8` itself is VALID ww — a sanctioned Go-like direct byte-index,
 * a deliberate divergence from Hare's `strings::toutf8(s)[i]` (the Hare
 * reference checker rejects str-index, harec check.c:362). lib/strings is
 * load-bearing on it (compare/dup/join). The reject is SCOPED to ONE operand
 * shape: a bare def-global SCALAR str.
 *
 * The bug (both-stage, but each side misbehaved DIFFERENTLY):
 *   - cstage: `def S:str="hi"; S[0]` BUILT and emitted an unbacked `main.S(SB)`
 *     base load — at runtime a frame-garbage base → SILENT SEGFAULT.
 *   - wwstage: the same source referenced an unbacked symbol → w6l LINK-FAIL.
 * A `def` is an inline compile-time CONSTANT (def-as-constant; not storage-
 * backed like a `let`), so it has no address to index. The fix REJECTS that
 * one operand at the checker (N_IDENT operand + SK_DEF sym + scalar TY_STR
 * base), surfacing a source error before cgen — segfault gone by construction.
 *
 * Mutation-sanity: the genuinely-silent pre-fix case is cstage's def-scalar
 * index, which BUILT (then segfaulted) — neg rows assert BUILD-FAIL, so they
 * FAIL pre-fix on cstage (built-ok) and pass post-fix. wwstage already
 * link-failed pre-fix.
 *
 *   neg row             | shape                                  | gate
 *   --------------------+----------------------------------------+----------
 *   def_scalar_index    | def S:str="hi", return S[0]:i32         | build FAIL
 *   def_scalar_varbind  | def S:str="hi", let c=S[1]              | build FAIL
 *
 *   pos row             | shape                                  | want
 *   --------------------+----------------------------------------+------
 *   let_scalar_index    | module let S:str="hi", S[0]:i32         | 104 ('h')
 *   param_index         | fn f(s:str) i32 = s[0]:i32; f("hi")     | 104 ('h')
 *   local_index         | local let s:str="hi", s[0]:i32          | 104 ('h')
 *   def_strarray_elem   | def C:[2]str=["ab","cd"], C[1][0]:i32   | 99  ('c')
 *
 * The def_strarray_elem row pins the #8 materialised array-element str stays
 * VALID: the outer operand `C[1]` is N_INDEX (not N_IDENT), so the scalar-str
 * gate excludes it; and a bare def str-ARRAY operand's base is TY_ARRAY (not
 * scalar str), also excluded. let/param/local + string-literal operands stay
 * valid (the lib/strings compare/dup pattern).
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/wait.h>

static int
runwait(const char *cmd)
{
	int rc = system(cmd);
	if (rc == -1) return -1;
	if (WIFEXITED(rc)) return WEXITSTATUS(rc);
	return -1;
}

struct row { const char *label; const char *src; int want; };

static const struct row rows[] = {
	/* module-level `let` str is storage-backed (DATA) → indexable. */
	{ "let_scalar_index",
	  "package main;\n"
	  "let S: str = \"hi\";\n"
	  "export fn main() i32 = {\n"
	  "\treturn S[0]: i32;\n"
	  "};\n",
	  104 },

	{ "param_index",
	  "package main;\n"
	  "fn f(s: str) i32 = {\n"
	  "\treturn s[0]: i32;\n"
	  "};\n"
	  "export fn main() i32 = {\n"
	  "\treturn f(\"hi\");\n"
	  "};\n",
	  104 },

	{ "local_index",
	  "package main;\n"
	  "export fn main() i32 = {\n"
	  "\tlet s: str = \"hi\";\n"
	  "\treturn s[0]: i32;\n"
	  "};\n",
	  104 },

	/* #8 materialised array-element str — `C[1]` is N_INDEX, not N_IDENT,
	 * so the def-scalar-str gate excludes it; must STAY valid. */
	{ "def_strarray_elem",
	  "package main;\n"
	  "def C: [2]str = [\"ab\", \"cd\"];\n"
	  "export fn main() i32 = {\n"
	  "\treturn C[1][0]: i32;\n"
	  "};\n",
	  99 },

	/* CRITICAL PRESERVE — INTERP-style def-global scalar str `.len`/`.ptr`
	 * N_DOT FIELD read (lib w6l/dynout.ww INTERP, load-bearing in the ELF
	 * emit; bootstrap dies if this breaks). The #14 reject is on N_INDEX,
	 * NOT N_DOT — this field read must STAY valid. 3 + *"abc".ptr(='a'=97)
	 * = 100. */
	{ "def_scalar_field",
	  "package main;\n"
	  "def S: str = \"abc\";\n"
	  "export fn main() i32 = {\n"
	  "\tlet n: i32 = S.len: i32;\n"
	  "\tlet p: *u8 = S.ptr;\n"
	  "\treturn n + (*p): i32;\n"
	  "};\n",
	  100 },

	/* def-global NON-str array index — the scalar-str gate (TY_STR only)
	 * must NOT over-catch a legit def-array index (the #8 array path). */
	{ "def_arr_index",
	  "package main;\n"
	  "def A: [3]int = [10, 20, 30];\n"
	  "export fn main() i32 = {\n"
	  "\treturn A[1]: i32;\n"
	  "};\n",
	  20 },
};

/* Indexing a bare def-global scalar str — both stages must FAIL the build
 * (loud checker diagnostic, not silent segfault / link-error). */
static const char *neg[] = {
	/* def_scalar_index */
	"package main;\n"
	"def S: str = \"hi\";\n"
	"export fn main() i32 = {\n"
	"\treturn S[0]: i32;\n"
	"};\n",
	/* def_scalar_varbind */
	"package main;\n"
	"def S: str = \"hi\";\n"
	"export fn main() i32 = {\n"
	"\tlet c = S[1];\n"
	"\treturn c: i32;\n"
	"};\n",
};

/* Per-neg expected diagnostic body (parallel to neg[]); both rows hit the
 * same "cannot index a def-constant str" path on both stages. */
static const char *neg_diag[] = {
	"cannot index a def-constant str",
	"cannot index a def-constant str",
};

static int
run_driver(const char *driver, const struct row *r, int i)
{
	char tmpdir[64], src[128], outbin[128], cmd[1024], rmcmd[160];
	snprintf(tmpdir, sizeof tmpdir, "/tmp/dsi_%d_d_%d", getpid(), i);
	mkdir(tmpdir, 0755);
	snprintf(src, sizeof src, "%s/dsi_%d_%d.ww", tmpdir, getpid(), i);
	snprintf(outbin, sizeof outbin, "%s/dsi_%d_%d", tmpdir, getpid(), i);
	snprintf(rmcmd, sizeof rmcmd, "rm -rf %s", tmpdir);

	FILE *f = fopen(src, "wb");
	if (!f) { runwait(rmcmd); return -1; }
	fputs(r->src, f);
	fclose(f);

	/* #8: -o pins binary + .sepwork scratch under tmpdir; rm -rf on
	 * every exit path removes the now-non-empty dir. */
	snprintf(cmd, sizeof cmd, "%s build -o %s %s 2>/dev/null",
	    driver, outbin, src);
	if (runwait(cmd) != 0) {
		fprintf(stderr, "row[%s]: build via %s failed\n",
		    r->label, driver);
		runwait(rmcmd);
		return -1;
	}

	int got = runwait(outbin);

	runwait(rmcmd);
	return got;
}

static int
filehas(const char *path, const char *needle)
{
	char buf[8192];
	FILE *f = fopen(path, "rb");
	if (!f) return 0;
	size_t n = fread(buf, 1, sizeof buf - 1, f);
	fclose(f);
	buf[n] = '\0';
	return strstr(buf, needle) != NULL;
}

/* build_should_fail — indexing a def-global scalar str must error on
 * `driver`; returns 0 when the build FAILS *and* emits `diag`. A crash
 * (segfault) wraps as a nonzero "w6c failed" with no diagnostic, so the
 * substring distinguishes it from a clean reject (#20). */
static int
build_should_fail(const char *driver, const char *src, const char *diag,
    int i)
{
	char tmpdir[64], s[128], outbin[128], cmd[1024], errf[128], rmcmd[160];
	snprintf(tmpdir, sizeof tmpdir, "/tmp/dsin_%d_d_%d", getpid(), i);
	mkdir(tmpdir, 0755);
	snprintf(s, sizeof s, "%s/dsin_%d_%d.ww", tmpdir, getpid(), i);
	snprintf(outbin, sizeof outbin, "%s/dsin_%d_%d", tmpdir, getpid(), i);
	snprintf(errf, sizeof errf, "%s/err", tmpdir);
	snprintf(rmcmd, sizeof rmcmd, "rm -rf %s", tmpdir);

	FILE *f = fopen(s, "wb");
	if (!f) { runwait(rmcmd); return -1; }
	fputs(src, f);
	fclose(f);

	/* #8: -o pins binary + any .sepwork scratch under tmpdir; rm -rf
	 * removes the now-non-empty dir. */
	snprintf(cmd, sizeof cmd, "%s build -o %s %s >/dev/null 2>%s",
	    driver, outbin, s, errf);
	int rc = runwait(cmd);
	int hasmsg = filehas(errf, diag);
	runwait(rmcmd);
	/* build must NOT succeed AND must emit its diagnostic. */
	return (rc != 0 && hasmsg) ? 0 : -1;
}

/* asm_byte_identical — w6c vs w6c_ww .s for the same source must match. */
static int
asm_byte_identical(const char *bin, const struct row *r, int i)
{
	char src[64], cs[64], ws[64], cmd[1024];
	snprintf(src, sizeof src, "/tmp/dsi_asm_%d_%d.ww", getpid(), i);
	snprintf(cs,  sizeof cs,  "/tmp/dsi_asm_%d_%d_c.s", getpid(), i);
	snprintf(ws,  sizeof ws,  "/tmp/dsi_asm_%d_%d_w.s", getpid(), i);

	FILE *f = fopen(src, "wb");
	if (!f) return -1;
	fputs(r->src, f);
	fclose(f);

	snprintf(cmd, sizeof cmd, "%s/w6c -o %s %s 2>/dev/null", bin, cs, src);
	if (runwait(cmd) != 0) {
		fprintf(stderr, "row[%s]: w6c errored\n", r->label);
		unlink(src);
		return -1;
	}
	snprintf(cmd, sizeof cmd, "%s/w6c_ww -o %s %s 2>/dev/null",
	    bin, ws, src);
	if (runwait(cmd) != 0) {
		fprintf(stderr, "row[%s]: w6c_ww errored\n", r->label);
		unlink(src); unlink(cs);
		return -1;
	}

	FILE *fc = fopen(cs, "rb");
	FILE *fw = fopen(ws, "rb");
	int rc = 0;
	if (!fc || !fw) {
		rc = -1;
	} else {
		for (;;) {
			int a = fgetc(fc);
			int b = fgetc(fw);
			if (a != b) { rc = -1; break; }
			if (a == EOF) break;
		}
	}
	if (fc) fclose(fc);
	if (fw) fclose(fw);
	if (rc != 0)
		fprintf(stderr, "row[%s]: cstage vs wwstage asm differs\n",
		    r->label);
	unlink(src); unlink(cs); unlink(ws);
	return rc;
}

int
main(void)
{
	const char *bin = getenv("BIN");
	if (!bin) bin = "out/bin";
	char absbin[1024];
	if (bin[0] != '/') {
		char cwd[1024];
		if (getcwd(cwd, sizeof cwd) == NULL) return 1;
		snprintf(absbin, sizeof absbin, "%s/%s", cwd, bin);
		bin = absbin;
	}

	char cdrv[1024];
	snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
	char wdrv[1024];
	snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);

	struct { const char *name; const char *path; int gated_on_existence; }
	drivers[] = {
		{ "cstage",  cdrv, 0 },
		{ "wwstage", wdrv, 1 },
		{ NULL, NULL, 0 },
	};

	int n = (int)(sizeof rows / sizeof rows[0]);
	int nn = (int)(sizeof neg / sizeof neg[0]);
	int total = 0, fail = 0;

	for (int d = 0; drivers[d].name; d++) {
		if (drivers[d].gated_on_existence
		    && access(drivers[d].path, X_OK) != 0) {
			fprintf(stderr, "def_str_index_reject: skip %s (no %s)\n",
			    drivers[d].name, drivers[d].path);
			continue;
		}
		for (int i = 0; i < n; i++) {
			int got = run_driver(drivers[d].path, &rows[i], i);
			total++;
			if (got != rows[i].want) {
				fprintf(stderr,
				    "def_str_index_reject[%s][%s]: exit=%d want=%d\n",
				    drivers[d].name, rows[i].label,
				    got, rows[i].want);
				fail++;
			}
		}
		for (int i = 0; i < nn; i++) {
			total++;
			if (build_should_fail(drivers[d].path, neg[i],
			    neg_diag[i], 100 + i) != 0) {
				fprintf(stderr,
				    "def_str_index_reject[%s][neg%d]: built ok, "
				    "expected a loud error\n",
				    drivers[d].name, i);
				fail++;
			}
		}
	}

	if (access(wdrv, X_OK) == 0) {
		for (int i = 0; i < n; i++) {
			total++;
			if (asm_byte_identical(bin, &rows[i], i) != 0)
				fail++;
		}
	}

	if (fail) {
		fprintf(stderr,
		    "def_str_index_reject: %d/%d fixtures failed\n", fail, total);
		return 1;
	}
	printf("def_str_index_reject: %d/%d ok\n", total, total);
	return 0;
}