ww/test/wcc/787_xmod_variant_match.c

/*
 * 787_xmod_variant_match — project #13 close. Pins that a `package main`
 * can decompose an IMPORTED union's individual VARIANTS cross-module
 * (`match (e: pkg.u) { case pkg.a => ...; case let o: pkg.b => ... }`),
 * on BOTH stages, byte-identically (rule-10).
 *
 * THE BUG (wwstage-CHECKER-only, cs!=ww): wwstage's match-arm validity
 * (selfhost/cmd/wcc/check.ww casevariantin) and exhaustiveness
 * (casecovers) compared via typeeqast, whose N_TNAME arm is a raw
 * streq. A union's variant is written UNQUALIFIED in its defining
 * module (`a` in pkg.u's body); the cross-module case pattern is the
 * dotted `pkg.a` (one N_TNAME). streq("a","pkg.a") -> false -> wwstage
 * rejected "case: not a variant of scrutinee". cstage compares
 * resolved-Type identity (variant_match, cmd/wcc/check.c:1651), so the
 * qualifier is irrelevant and it built+routed correctly. Hare allows
 * cross-module variant decomposition; align UP to cstage (a too-strict
 * checker, NOT a down-align that would forbid the feature).
 *
 * THE FIX (#13): casevariantpairmatch reduces BOTH pattern and variant
 * to a (module, leaf) pair — a dotted name keeps its own qualifier, a
 * bare name is attributed the union's defining module (taggeddefmod via
 * aliassym .decl.nmod) — and matches the pairs. This accepts a
 * cross-module `case errors.unsupported` (vs bare `unsupported`) while
 * REJECTING a foreign `othermod.unsupported`, and keeps a dotted body
 * variant matching its own qualifier (Shape A). Wired into BOTH
 * casevariantin (validity) and casecovers (exhaustiveness). #10-family
 * (AST-name vs cstage tinfo); precise Type identity is the #10 endgame.
 *
 * The PRE-FIX failure mode is a wwstage CHECKER REJECT, so the
 * discriminator is the `w6c_ww` build of the combined.ww succeeding at
 * all — pre-fix it errored out; post-fix it succeeds AND is byte-id
 * with cstage. Self-contained 2-module fixtures (no lib coupling).
 *
 *   scenario          | shape                                  | exit | byte-id
 *   ------------------+----------------------------------------+------+--------
 *   no_default        | match pkg.u=!(a|b), bare arms, NO      |  21  | cs==ww
 *                     |   default — exercises casecovers       |      |
 *                     |   exhaustiveness cross-module          |      |
 *   bind_and_default  | match pkg.u2=!(a|b|c): bare arm + a    |  42  | cs==ww
 *                     |   `case let o: pkg.b` BOUND arm + a     |      |
 *                     |   `case =>` default; if-checks each arm |      |
 *   foreign_qualifier | `case o.a` vs pkg.u (o.a is a DIFFERENT | both | (reject
 *                     |   module's same-leaf type) — BOTH       |reject|  net)
 *                     |   stages must REJECT; guards the fix    |      |
 *                     |   against a false-ACCEPT (bare leaf-    |      |
 *                     |   strip would wrongly accept)           |      |
 *   shape_a_dotted_var| union BODY holds dotted variant         |  12  | cs==ww
 *                     |   pkg.e=!(errs.bad|local); case errs.bad|      |
 *                     |   keeps OWN qualifier (drew Shape A) —   |      |
 *                     |   sole positive lock on qualmod's       |      |
 *                     |   dotted-variant branch                 |      |
 *
 * GATE POLARITY: must stay GREEN. Red means wwstage rejected a valid
 * cross-module variant match again (w6c_ww build fails) or the routing
 * diverged (byte-id / runtime).
 */
#include <stdio.h>
#include <stdlib.h>
#include <errno.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;
}

static int
slurp_eq(const char *a, const char *b)
{
	FILE *fa = fopen(a, "rb");
	FILE *fb = fopen(b, "rb");
	if (!fa || !fb) { if (fa) fclose(fa); if (fb) fclose(fb); return -1; }
	int rc = 0;
	for (;;) {
		int ca = fgetc(fa);
		int cb = fgetc(fb);
		if (ca != cb) { rc = -1; break; }
		if (ca == EOF) break;
	}
	if (ferror(fa) || ferror(fb)) rc = -1;
	if (fclose(fa) != 0) rc = -1;
	if (fclose(fb) != 0) rc = -1;
	return rc;
}

struct file { const char *name; const char *src; };

struct scenario {
	const char *label;
	const struct file *files;	/* name==NULL terminates */
	int want_exit;
	int expect_reject;		/* 1 = BOTH stages must REJECT (checker) */
};

/* ---- no_default: bare cross-module arms, no default (exhaustiveness) */
static const struct file no_default_files[] = {
	{ "pkg.ww",
	  "package pkg;\n"
	  "export type a = !void;\n"
	  "export type b = !void;\n"
	  "export type u = !(a | b);\n"
	  "export fn mka() u = { let x: a; return x; };\n"
	  "export fn mkb() u = { let y: b; return y; };\n" },
	{ "main.ww",
	  "package main;\n"
	  "import pkg;\n"
	  "fn classify(e: pkg.u) i32 = {\n"
	  "	match (e) {\n"
	  "	case pkg.a => return 1;\n"
	  "	case pkg.b => return 2;\n"
	  "	};\n"
	  "};\n"
	  "export fn main() i32 = {\n"
	  "	return classify(pkg.mkb()) * 10 + classify(pkg.mka());\n"
	  "};\n" },
	{ NULL, NULL }
};

/* ---- bind_and_default: bound arm + default cross-module ----------- */
static const struct file bind_default_files[] = {
	{ "pkg.ww",
	  "package pkg;\n"
	  "export type a = !void;\n"
	  "export type b = !void;\n"
	  "export type c = !void;\n"
	  "export type u2 = !(a | b | c);\n"
	  "export fn mka() u2 = { let x: a; return x; };\n"
	  "export fn mkb() u2 = { let y: b; return y; };\n"
	  "export fn mkc() u2 = { let z: c; return z; };\n" },
	{ "main.ww",
	  "package main;\n"
	  "import pkg;\n"
	  "fn classify(e: pkg.u2) i32 = {\n"
	  "	match (e) {\n"
	  "	case pkg.a => return 1;\n"
	  "	case let o: pkg.b => return 2;\n"
	  "	case => return 9;\n"
	  "	};\n"
	  "};\n"
	  "export fn main() i32 = {\n"
	  "	if (classify(pkg.mka()) != 1) { return 11; };\n"
	  "	if (classify(pkg.mkb()) != 2) { return 12; };\n"
	  "	if (classify(pkg.mkc()) != 9) { return 13; };\n"
	  "	return 42;\n"
	  "};\n" },
	{ NULL, NULL }
};

/* ---- foreign_qualifier: a same-leaf variant from a DIFFERENT module
 * is NOT a variant of the scrutinee — BOTH stages must REJECT. Guards
 * the #13 fix against trading the false-reject for a false-ACCEPT: a
 * bare leaf-strip would wrongly accept `o.a` (leaf "a" matches pkg's
 * variant `a`); the (module,leaf)-pair match rejects it (o != pkg). */
static const struct file foreign_qualifier_files[] = {
	{ "pkg.ww",
	  "package pkg;\n"
	  "export type a = !void;\n"
	  "export type b = !void;\n"
	  "export type u = !(a | b);\n"
	  "export fn mka() u = { let x: a; return x; };\n" },
	{ "o.ww",
	  "package o;\n"
	  "export type a = !void;\n" },
	{ "main.ww",
	  "package main;\n"
	  "import pkg;\n"
	  "import o;\n"
	  "fn classify(e: pkg.u) i32 = {\n"
	  "	match (e) {\n"
	  "	case o.a => return 1;\n"
	  "	case => return 0;\n"
	  "	};\n"
	  "};\n"
	  "export fn main() i32 = { return classify(pkg.mka()); };\n" },
	{ NULL, NULL }
};

/* ---- shape_a_dotted_variant: the union's BODY itself holds a dotted
 * cross-module variant (`pkg.e = !(errs.bad | local)`), matched with a
 * dotted `case errs.bad` AND a bare-variant `case pkg.local`. This is
 * drew's Shape A (cf. io.error nesting errors.error): the dotted body
 * variant `errs.bad` must keep ITS OWN qualifier (errs), NOT be forced
 * onto the union's defining module (pkg) — else `case errs.bad` would
 * false-REJECT. The other three scenarios carry only BARE body variants,
 * so this is the sole positive lock on qualmod's dotted-variant branch;
 * a regression that attributes unionmod to every variant breaks here
 * alone. exit = classify(mkbad())*10 + classify(mklocal()) = 1*10+2. */
static const struct file shape_a_files[] = {
	{ "errs.ww",
	  "package errs;\n"
	  "export type bad = !void;\n" },
	{ "pkg.ww",
	  "package pkg;\n"
	  "import errs;\n"
	  "export type local = !void;\n"
	  "export type e = !(errs.bad | local);\n"
	  "export fn mkbad() e = { let x: errs.bad; return x; };\n"
	  "export fn mklocal() e = { let y: local; return y; };\n" },
	{ "main.ww",
	  "package main;\n"
	  "import pkg;\n"
	  "import errs;\n"
	  "fn classify(x: pkg.e) i32 = {\n"
	  "	match (x) {\n"
	  "	case errs.bad => return 1;\n"
	  "	case pkg.local => return 2;\n"
	  "	};\n"
	  "};\n"
	  "export fn main() i32 = {\n"
	  "	return classify(pkg.mkbad()) * 10 + classify(pkg.mklocal());\n"
	  "};\n" },
	{ NULL, NULL }
};

static const struct scenario scenarios[] = {
	{ "no_default",         no_default_files,        21, 0 },
	{ "bind_and_default",   bind_default_files,      42, 0 },
	{ "foreign_qualifier",  foreign_qualifier_files,  0, 1 },
	{ "shape_a_dotted_var", shape_a_files,           12, 0 },
};

static int
run_scenario(const char *bin, const char *cdrv, const char *wdrv,
    const struct scenario *sc)
{
	(void)bin;
	char dir[] = "/tmp/ww787_XXXXXX";
	if (mkdtemp(dir) == NULL) {
		fprintf(stderr, "787[%s]: mkdtemp failed\n", sc->label);
		return -1;
	}

	char path[1024], cmd[4096];
	int rc = 0;

	for (int i = 0; sc->files[i].name; i++) {
		snprintf(path, sizeof path, "%s/%s", dir, sc->files[i].name);
		FILE *f = fopen(path, "wb");
		if (!f) { fprintf(stderr, "787[%s]: write %s\n", sc->label,
		    sc->files[i].name); rc = -1; goto done; }
		int bad = fputs(sc->files[i].src, f) == EOF;
		if (fclose(f) != 0) bad = 1;
		if (bad) { fprintf(stderr, "787[%s]: write %s\n", sc->label,
		    sc->files[i].name); rc = -1; goto done; }
	}

	if (sc->expect_reject) {
		/* #94 sep layout: there is no combined unit to re-check. The
		 * checker reject now fires inside each driver's w6c pass,
		 * so BOTH driver builds MUST fail. w6c_ww (via ww_ww) accepting
		 * here is the #13 false-ACCEPT regression. */
		snprintf(cmd, sizeof cmd,
		    "cd %s && %s build -I %s "
		    "-o %s/main %s/main.ww >/dev/null 2>&1",
		    dir, cdrv, dir, dir, dir);
		if (runwait(cmd) == 0) {
			fprintf(stderr, "787[%s]: cstage build SUCCEEDED, "
			    "expected reject\n", sc->label);
			rc = -1; goto done;
		}
		snprintf(cmd, sizeof cmd,
		    "cd %s && %s build -I %s "
		    "-o %s/mainww %s/main.ww >/dev/null 2>&1",
		    dir, wdrv, dir, dir, dir);
		if (runwait(cmd) == 0) {
			fprintf(stderr, "787[%s]: ww_ww ACCEPTED foreign variant "
			    "(#13 false-accept), expected reject\n", sc->label);
			rc = -1; goto done;
		}
		goto done;
	}

	/* cstage driver build + run: pins runtime routing. Pin
	 * all outputs stay under the scratch dir. */
	snprintf(cmd, sizeof cmd,
	    "cd %s && %s build -I %s -o %s/main %s/main.ww",
	    dir, cdrv, dir, dir, dir);
	if (runwait(cmd) != 0) {
		fprintf(stderr, "787[%s]: cstage build failed\n", sc->label);
		rc = -1; goto done;
	}
	snprintf(path, sizeof path, "%s/main", dir);
	int got = runwait(path);
	if (got != sc->want_exit) {
		fprintf(stderr, "787[%s]: cstage exit %d, want %d\n",
		    sc->label, got, sc->want_exit);
		rc = -1;
	}

	/* The #13 discriminator: the wwstage driver's build runs the
	 * wwstage checker over the same units. Pre-fix it REJECTED the
	 * cross-module variant arms (build fails); post-fix it accepts AND
	 * its per-package w6c_ww asm is byte-id with cstage's. The root +
	 * each imported pkg compile to separate <stem>.sepwork/<pkg>.s;
	 * concat (sorted glob, identical set both stages) for the compare. */
	snprintf(cmd, sizeof cmd,
	    "cd %s && %s build -I %s -o %s/mainww %s/main.ww",
	    dir, wdrv, dir, dir, dir);
	if (runwait(cmd) != 0) {
		fprintf(stderr, "787[%s]: ww_ww build failed "
		    "(#13 cross-module variant reject?)\n", sc->label);
		rc = -1; goto done;
	}
	char cs_s[1024], ws_s[1024];
	snprintf(cs_s, sizeof cs_s, "%s/all_cs.s", dir);
	snprintf(ws_s, sizeof ws_s, "%s/all_ww.s", dir);
	snprintf(cmd, sizeof cmd,
	    "cat %s/main.sepwork/*.s > %s 2>/dev/null && test -s %s",
	    dir, cs_s, cs_s);
	if (runwait(cmd) != 0) {
		fprintf(stderr, "787[%s]: cstage asm aggregation failed\n",
		    sc->label);
		rc = -1; goto done;
	}
	snprintf(cmd, sizeof cmd,
	    "cat %s/mainww.sepwork/*.s > %s 2>/dev/null && test -s %s",
	    dir, ws_s, ws_s);
	if (runwait(cmd) != 0) {
		fprintf(stderr, "787[%s]: wwstage asm aggregation failed\n",
		    sc->label);
		rc = -1; goto done;
	}
	if (slurp_eq(cs_s, ws_s) != 0) {
		fprintf(stderr, "787[%s]: cs.s/ww.s DIFFER (rule-10 byte-id "
		    "violation)\n", sc->label);
		rc = -1;
	}

done:
	snprintf(cmd, sizeof cmd, "rm -rf %s/main.sepwork", dir);
	if (runwait(cmd) != 0) { fprintf(stderr, "787[%s]: cleanup main.sepwork\n",
	    sc->label); rc = -1; }
	snprintf(cmd, sizeof cmd, "rm -rf %s/mainww.sepwork", dir);
	if (runwait(cmd) != 0) { fprintf(stderr, "787[%s]: cleanup mainww.sepwork\n",
	    sc->label); rc = -1; }
	for (int i = 0; sc->files[i].name; i++) {
		snprintf(path, sizeof path, "%s/%s", dir, sc->files[i].name);
		if (unlink(path) != 0 && errno != ENOENT) {
			fprintf(stderr, "787[%s]: cleanup %s\n", sc->label,
			    sc->files[i].name);
			rc = -1;
		}
	}
	const char *children[] = { "main", "mainww", "all_cs.s", "all_ww.s", NULL };
	for (int i = 0; children[i]; i++) {
		snprintf(path, sizeof path, "%s/%s", dir, children[i]);
		if (unlink(path) != 0 && errno != ENOENT) {
			fprintf(stderr, "787[%s]: cleanup %s\n", sc->label,
			    children[i]);
			rc = -1;
		}
	}
	if (rmdir(dir) != 0) {
		fprintf(stderr, "787[%s]: cleanup directory\n", sc->label);
		rc = -1;
	}
	return rc;
}

int
main(void)
{
	const char *bin = getenv("BIN");
	if (!bin) bin = "out/bin";
	char absbin[2048];
	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[2100], wdrv[2100];
	snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
	snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);
	if (access(wdrv, X_OK) != 0) {
		fprintf(stderr, "787: ww_ww missing — cannot run the cs==ww "
		    "byte-id gate (the whole point of this test)\n");
		return 1;
	}

	int n = (int)(sizeof scenarios / sizeof scenarios[0]);
	int fail = 0;
	for (int i = 0; i < n; i++) {
		if (run_scenario(bin, cdrv, wdrv, &scenarios[i]) != 0)
			fail++;
	}

	if (fail) {
		fprintf(stderr, "787 xmod_variant_match: %d/%d scenarios failed\n",
		    fail, n);
		return 1;
	}
	printf("xmod_variant_match: %d/%d ok (cstage run + cs==ww byte-id)\n",
	    n, n);
	return 0;
}