javascript: a computed table read defaulted inline or by reassignment names every function the table holds

graph/javascript/engine/call-edge-generation/partial-dispatch.dl

@@ -58,12 +58,27 @@ swallowed_read(e, i) :- expr_kind(_, "ELEMENT_ACCESS", _, e),
     expr_kind(_, "BINARY", _, key), expr_operator(_, op, key), default_op(op),
     expr_child(_, e, "ACCESS_TARGET", _, r), expr_value(r, "obj", i).
 
+// ── the variable a site calls through, and every value written into it ─────
+// Its initializer and each assignment (`h = d`, `h ??= d`, `h ||= d`).
+var_source(v, e) :- var_init(_, _, e, v).
+var_source(v, e) :- expr_kind(_, "ASSIGNMENT", _, a), expr_child(_, a, "ASSIGNMENT_TARGET", _, tgt),
+    expr_binding(_, v, tgt), expr_child(_, a, "ASSIGNMENT_VALUE", _, e).
+// A default BY REASSIGNMENT: `let h = t[k]; if (!h) h = d;`, `h ??= d`, or the other
+// way round. The variable holds the open read and something else, so the value layer
+// sees only the something else and asserts it; the read is swallowed all the same.
+swallowed_var(v, i) :- var_source(v, e), open_read(e, i), var_source(v, o), o != e.
+// A default written INTO the variable: `const h = t[k] || d`, or `h = t[k] || d`.
+swallowed_var(v, i) :- var_source(v, e), expr_child(_, e, _, _, o), swallowed_read(o, i).
+
 // ── partial_dispatch(CallExpr) ─────────────────────────────────────────────
-// The site invokes such a read: written at the site, or one hop through the const
-// it was assigned to, which is how both real shapes are written.
+// The site invokes such a read: written at the site (`t[k]()`, or the default itself
+// as the callee, `(t[k] || d)()`, whose parentheses the parser drops), or through the
+// variable it was stored in.
 partial_dispatch(ce) :- invocation_site(ce, _), expr_child(_, ce, "CALLEE", _, c), swallowed_read(c, _).
 partial_dispatch(ce) :- invocation_site(ce, _), expr_child(_, ce, "CALLEE", _, c),
-    expr_binding(_, v, c), var_init(_, _, ie, v), expr_child(_, ie, _, _, o), swallowed_read(o, _).
+    expr_child(_, c, _, _, o), swallowed_read(o, _).
+partial_dispatch(ce) :- invocation_site(ce, _), expr_child(_, ce, "CALLEE", _, c),
+    expr_binding(_, v, c), swallowed_var(v, _).
 // `resolvers[<default>](...)`: the parser puts the object under RECEIVER and the key
 // under COMPUTED_KEY on the call itself, with no ELEMENT_ACCESS node of its own.
 partial_dispatch(ce) :- call_site(_, "COMPUTED_CALL", _, _, _, _, ce, _, _),
@@ -75,8 +90,9 @@ partial_dispatch(ce) :- call_site(_, "COMPUTED_CALL", _, _, _, _, ce, _, _),
 partial_dispatch_target(ce, m) :- invocation_site(ce, _), expr_child(_, ce, "CALLEE", _, c),
     swallowed_read(c, i), prop_value("obj", i, _, "func", m).
 partial_dispatch_target(ce, m) :- invocation_site(ce, _), expr_child(_, ce, "CALLEE", _, c),
-    expr_binding(_, v, c), var_init(_, _, ie, v), expr_child(_, ie, _, _, o),
-    swallowed_read(o, i), prop_value("obj", i, _, "func", m).
+    expr_child(_, c, _, _, o), swallowed_read(o, i), prop_value("obj", i, _, "func", m).
+partial_dispatch_target(ce, m) :- invocation_site(ce, _), expr_child(_, ce, "CALLEE", _, c),
+    expr_binding(_, v, c), swallowed_var(v, i), prop_value("obj", i, _, "func", m).
 partial_dispatch_target(ce, m) :- call_site(_, "COMPUTED_CALL", _, _, _, _, ce, _, _),
     expr_child(_, ce, "COMPUTED_KEY", _, key),
     expr_kind(_, "BINARY", _, key), expr_operator(_, op, key), default_op(op),

graph/javascript/souffle/decls_all.dl

@@ -295,6 +295,8 @@
 .decl swallowed_read(c0:symbol, c1:symbol)
 .decl partial_dispatch(c0:symbol)
 .decl partial_dispatch_target(c0:symbol, c1:symbol)
+.decl var_source(c0:symbol, c1:symbol)
+.decl swallowed_var(c0:symbol, c1:symbol)
 // the same read with no default beside it, called: one of the literal's functions
 .decl open_read(c0:symbol, c1:symbol)
 .decl open_dispatch_target(c0:symbol, c1:symbol)

graph/test/javascript/cases/70-dispatch-table-default-inline-or-reassigned/src/main.js

@@ -0,0 +1,79 @@
+// A DISPATCH TABLE read with a computed key and defaulted, written without a const
+// between the default and the call (#1727). Case 61 pins `const h = t[k] || d; h()`;
+// these are the same default written inline, or by assigning the variable again. The
+// value layer sees only the default, so each used to be a known_edge to it alone.
+import { remote } from './table.js';
+
+function fromA(a) { return a; }
+function fromB(a) { return a; }
+function deep(a) { return [a]; }
+
+const table = { a: fromA, b: fromB };
+
+// THE CONSTRUCT, inline: the default is the callee, `(t[k] || d)()`.
+function inlineOr(k, a) { return (table[k] || deep)(a); }
+
+// THE CONSTRUCT, inline with a conditional.
+function inlineTernary(k, a) { return (k in table ? table[k] : deep)(a); }
+
+// THE CONSTRUCT, by reassignment: `if (!h) h = d`.
+function reassigned(k, a) {
+  let h = table[k];
+  if (!h) h = deep;
+  return h(a);
+}
+
+// THE CONSTRUCT, by a logical assignment.
+function nullishAssigned(k, a) {
+  let h = table[k];
+  h ??= deep;
+  return h(a);
+}
+
+// THE CONSTRUCT, the other way round: the default first, the read assigned over it.
+function readAssigned(k, a) {
+  let h = deep;
+  if (k) h = table[k];
+  return h(a);
+}
+
+// THE CONSTRUCT, the table imported from another module.
+function importedInline(k, a) { return (remote[k] || deep)(a); }
+function importedReassigned(k, a) {
+  let h = remote[k];
+  if (!h) h = deep;
+  return h(a);
+}
+
+// CONTROL 1: an inline default whose key is WRITTEN AS A LITERAL: fromA and deep only.
+function inlineLiteralKey(a) { return (table['a'] || deep)(a); }
+
+// CONTROL 2: a dotted read reassigned: fromB and deep only.
+function reassignedDotted(a) {
+  let h = table.b;
+  if (!h) h = deep;
+  return h(a);
+}
+
+// CONTROL 3: a variable reassigned with no table read at all: fromA and deep only.
+function reassignedPlain(k, a) {
+  let h = fromA;
+  if (k) h = deep;
+  return h(a);
+}
+
+// CONTROL 4: the default alone, inline. The one known target stays a known_edge.
+function inlineDefaultOnly(k, a) { return (k || deep)(a); }
+
+const key = process.argv[2];
+inlineOr(key, 1);
+inlineTernary(key, 1);
+reassigned(key, 1);
+nullishAssigned(key, 1);
+readAssigned(key, 1);
+importedInline(key, 1);
+importedReassigned(key, 1);
+inlineLiteralKey(1);
+reassignedDotted(1);
+reassignedPlain(key, 1);
+inlineDefaultOnly(key, 1);

graph/test/javascript/cases/70-dispatch-table-default-inline-or-reassigned/src/table.js

@@ -0,0 +1,3 @@
+function fromC(a) { return a; }
+function fromD(a) { return a; }
+export const remote = { c: fromC, d: fromD };

graph/test/javascript/expected/70-dispatch-table-default-inline-or-reassigned.diag

@@ -0,0 +1 @@
+package_entry    @axiomcode/code-graph  .  []  MAIN  dist/reason.js  NOT_STAGED  -> -

graph/test/javascript/expected/70-dispatch-table-default-inline-or-reassigned.edges

@@ -0,0 +1,40 @@
+main.js:14:34 FUNCTION_CALL (table[k] || deep)  ->  multi_inferred  main.js:7:1 fromA
+main.js:14:34 FUNCTION_CALL (table[k] || deep)  ->  multi_inferred  main.js:8:1 fromB
+main.js:14:34 FUNCTION_CALL (table[k] || deep)  ->  multi_inferred  main.js:9:1 deep
+main.js:17:39 FUNCTION_CALL (k in table ? table[k] : deep)  ->  multi_inferred  main.js:7:1 fromA
+main.js:17:39 FUNCTION_CALL (k in table ? table[k] : deep)  ->  multi_inferred  main.js:8:1 fromB
+main.js:17:39 FUNCTION_CALL (k in table ? table[k] : deep)  ->  multi_inferred  main.js:9:1 deep
+main.js:23:10 FUNCTION_CALL h  ->  multi_inferred  main.js:7:1 fromA
+main.js:23:10 FUNCTION_CALL h  ->  multi_inferred  main.js:8:1 fromB
+main.js:23:10 FUNCTION_CALL h  ->  multi_inferred  main.js:9:1 deep
+main.js:30:10 FUNCTION_CALL h  ->  multi_inferred  main.js:7:1 fromA
+main.js:30:10 FUNCTION_CALL h  ->  multi_inferred  main.js:8:1 fromB
+main.js:30:10 FUNCTION_CALL h  ->  multi_inferred  main.js:9:1 deep
+main.js:37:10 FUNCTION_CALL h  ->  multi_inferred  main.js:7:1 fromA
+main.js:37:10 FUNCTION_CALL h  ->  multi_inferred  main.js:8:1 fromB
+main.js:37:10 FUNCTION_CALL h  ->  multi_inferred  main.js:9:1 deep
+main.js:41:40 FUNCTION_CALL (remote[k] || deep)  ->  multi_inferred  main.js:9:1 deep
+main.js:41:40 FUNCTION_CALL (remote[k] || deep)  ->  multi_inferred  table.js:1:1 fromC
+main.js:41:40 FUNCTION_CALL (remote[k] || deep)  ->  multi_inferred  table.js:2:1 fromD
+main.js:45:10 FUNCTION_CALL h  ->  multi_inferred  main.js:9:1 deep
+main.js:45:10 FUNCTION_CALL h  ->  multi_inferred  table.js:1:1 fromC
+main.js:45:10 FUNCTION_CALL h  ->  multi_inferred  table.js:2:1 fromD
+main.js:49:39 FUNCTION_CALL (table['a'] || deep)  ->  multi_inferred  main.js:7:1 fromA
+main.js:49:39 FUNCTION_CALL (table['a'] || deep)  ->  multi_inferred  main.js:9:1 deep
+main.js:55:10 FUNCTION_CALL h  ->  multi_inferred  main.js:8:1 fromB
+main.js:55:10 FUNCTION_CALL h  ->  multi_inferred  main.js:9:1 deep
+main.js:62:10 FUNCTION_CALL h  ->  multi_inferred  main.js:7:1 fromA
+main.js:62:10 FUNCTION_CALL h  ->  multi_inferred  main.js:9:1 deep
+main.js:66:43 FUNCTION_CALL (k || deep)  ->  ambient_terminal  -
+main.js:66:43 FUNCTION_CALL (k || deep)  ->  multi_inferred  main.js:9:1 deep
+main.js:69:1 FUNCTION_CALL inlineOr  ->  known_edge  main.js:14:1 inlineOr
+main.js:70:1 FUNCTION_CALL inlineTernary  ->  known_edge  main.js:17:1 inlineTernary
+main.js:71:1 FUNCTION_CALL reassigned  ->  known_edge  main.js:20:1 reassigned
+main.js:72:1 FUNCTION_CALL nullishAssigned  ->  known_edge  main.js:27:1 nullishAssigned
+main.js:73:1 FUNCTION_CALL readAssigned  ->  known_edge  main.js:34:1 readAssigned
+main.js:74:1 FUNCTION_CALL importedInline  ->  known_edge  main.js:41:1 importedInline
+main.js:75:1 FUNCTION_CALL importedReassigned  ->  known_edge  main.js:42:1 importedReassigned
+main.js:76:1 FUNCTION_CALL inlineLiteralKey  ->  known_edge  main.js:49:1 inlineLiteralKey
+main.js:77:1 FUNCTION_CALL reassignedDotted  ->  known_edge  main.js:52:1 reassignedDotted
+main.js:78:1 FUNCTION_CALL reassignedPlain  ->  known_edge  main.js:59:1 reassignedPlain
+main.js:79:1 FUNCTION_CALL inlineDefaultOnly  ->  known_edge  main.js:66:1 inlineDefaultOnly

graph/test/javascript/expected/70-dispatch-table-default-inline-or-reassigned.oracle

@@ -0,0 +1,15 @@
+main.js:37:10 FUNCTION_CALL h  SOUND_SUPERSET  main.js:7:1;main.js:8:1;main.js:9:1
+main.js:55:10 FUNCTION_CALL h  SOUND_SUPERSET  main.js:8:1;main.js:9:1
+main.js:62:10 FUNCTION_CALL h  SOUND_SUPERSET  main.js:7:1;main.js:9:1
+main.js:69:1 FUNCTION_CALL inlineOr  EXACT  main.js:14:1
+main.js:70:1 FUNCTION_CALL inlineTernary  EXACT  main.js:17:1
+main.js:71:1 FUNCTION_CALL reassigned  EXACT  main.js:20:1
+main.js:72:1 FUNCTION_CALL nullishAssigned  EXACT  main.js:27:1
+main.js:73:1 FUNCTION_CALL readAssigned  EXACT  main.js:34:1
+main.js:74:1 FUNCTION_CALL importedInline  EXACT  main.js:41:1
+main.js:75:1 FUNCTION_CALL importedReassigned  EXACT  main.js:42:1
+main.js:76:1 FUNCTION_CALL inlineLiteralKey  EXACT  main.js:49:1
+main.js:77:1 FUNCTION_CALL reassignedDotted  EXACT  main.js:52:1
+main.js:78:1 FUNCTION_CALL reassignedPlain  EXACT  main.js:59:1
+main.js:79:1 FUNCTION_CALL inlineDefaultOnly  EXACT  main.js:66:1
+# defects: 0