fix: noop location (#1218)

Author: jorgsowa

src/ast.js

@@ -377,16 +377,25 @@ AST.prototype.prepare = function (kind, docs, parser) {
     const args = Array.prototype.slice.call(arguments);
     args.push(docs);
     if (self.withPositions || self.withSource) {
+      let nodeStart = start;
+      let nodeEnd = new Position(
+        parser.prev[0],
+        parser.prev[1],
+        parser.prev[2],
+      );
+      // Fix swapped positions when no tokens are consumed between node() and ()
+      // (e.g. noop node in an empty block that contains only comments)
+      if (nodeStart.offset > nodeEnd.offset) {
+        const tmp = nodeStart;
+        nodeStart = nodeEnd;
+        nodeEnd = tmp;
+      }
       let src = null;
       if (self.withSource) {
-        src = parser.lexer._input.substring(start.offset, parser.prev[2]);
+        src = parser.lexer._input.substring(nodeStart.offset, nodeEnd.offset);
       }
       // if with source, need location on swapLocations function
-      const location = new Location(
-        src,
-        start,
-        new Position(parser.prev[0], parser.prev[1], parser.prev[2]),
-      );
+      const location = new Location(src, nodeStart, nodeEnd);
       // last argument is always the location
       args.push(location);
     }

test/snapshot/__snapshots__/acid.test.js.snap

@@ -2257,16 +2257,16 @@ Program {
                             "kind": "block",
                             "loc": Location {
                               "end": Position {
-                                "column": 19,
-                                "line": 63,
-                                "offset": 1314,
+                                "column": 8,
+                                "line": 64,
+                                "offset": 1323,
                               },
                               "source": "
         ",
                               "start": Position {
-                                "column": 8,
-                                "line": 64,
-                                "offset": 1323,
+                                "column": 19,
+                                "line": 63,
+                                "offset": 1314,
                               },
                             },
                           },
@@ -7619,15 +7619,15 @@ next:
                         "kind": "noop",
                         "loc": Location {
                           "end": Position {
-                            "column": 11,
+                            "column": 12,
                             "line": 141,
-                            "offset": 3029,
+                            "offset": 3030,
                           },
                           "source": " ",
                           "start": Position {
-                            "column": 12,
+                            "column": 11,
                             "line": 141,
-                            "offset": 3030,
+                            "offset": 3029,
                           },
                         },
                       },

test/snapshot/__snapshots__/location.test.js.snap

@@ -125,6 +125,190 @@ Program {
 }
 `;
 
+exports[`Test locations noop in comment-only body has correct start/end order 1`] = `
+Program {
+  "children": [
+    _Function {
+      "arguments": [],
+      "attrGroups": [],
+      "body": Block {
+        "children": [
+          Noop {
+            "kind": "noop",
+            "leadingComments": [
+              CommentBlock {
+                "kind": "commentblock",
+                "loc": Location {
+                  "end": Position {
+                    "column": 17,
+                    "line": 3,
+                    "offset": 35,
+                  },
+                  "source": "/* comment */",
+                  "start": Position {
+                    "column": 4,
+                    "line": 3,
+                    "offset": 22,
+                  },
+                },
+                "offset": 22,
+                "value": "/* comment */",
+              },
+              CommentLine {
+                "kind": "commentline",
+                "loc": Location {
+                  "end": Position {
+                    "column": 0,
+                    "line": 5,
+                    "offset": 60,
+                  },
+                  "source": "# $m[] = 'declare';
+",
+                  "start": Position {
+                    "column": 4,
+                    "line": 4,
+                    "offset": 40,
+                  },
+                },
+                "offset": 40,
+                "value": "# $m[] = 'declare';
+",
+              },
+            ],
+            "loc": Location {
+              "end": Position {
+                "column": 0,
+                "line": 5,
+                "offset": 60,
+              },
+              "source": "
+    /* comment */
+    # $m[] = 'declare';
+",
+              "start": Position {
+                "column": 1,
+                "line": 2,
+                "offset": 17,
+              },
+            },
+          },
+        ],
+        "kind": "block",
+        "loc": Location {
+          "end": Position {
+            "column": 1,
+            "line": 5,
+            "offset": 61,
+          },
+          "source": "{
+    /* comment */
+    # $m[] = 'declare';
+}",
+          "start": Position {
+            "column": 0,
+            "line": 2,
+            "offset": 16,
+          },
+        },
+      },
+      "byref": false,
+      "kind": "function",
+      "loc": Location {
+        "end": Position {
+          "column": 1,
+          "line": 5,
+          "offset": 61,
+        },
+        "source": "function test()",
+        "start": Position {
+          "column": 0,
+          "line": 1,
+          "offset": 0,
+        },
+      },
+      "name": Identifier {
+        "kind": "identifier",
+        "loc": Location {
+          "end": Position {
+            "column": 13,
+            "line": 1,
+            "offset": 13,
+          },
+          "source": "test",
+          "start": Position {
+            "column": 9,
+            "line": 1,
+            "offset": 9,
+          },
+        },
+        "name": "test",
+      },
+      "nullable": false,
+      "type": null,
+    },
+  ],
+  "comments": [
+    CommentBlock {
+      "kind": "commentblock",
+      "loc": Location {
+        "end": Position {
+          "column": 17,
+          "line": 3,
+          "offset": 35,
+        },
+        "source": "/* comment */",
+        "start": Position {
+          "column": 4,
+          "line": 3,
+          "offset": 22,
+        },
+      },
+      "offset": 22,
+      "value": "/* comment */",
+    },
+    CommentLine {
+      "kind": "commentline",
+      "loc": Location {
+        "end": Position {
+          "column": 0,
+          "line": 5,
+          "offset": 60,
+        },
+        "source": "# $m[] = 'declare';
+",
+        "start": Position {
+          "column": 4,
+          "line": 4,
+          "offset": 40,
+        },
+      },
+      "offset": 40,
+      "value": "# $m[] = 'declare';
+",
+    },
+  ],
+  "errors": [],
+  "kind": "program",
+  "loc": Location {
+    "end": Position {
+      "column": 1,
+      "line": 5,
+      "offset": 61,
+    },
+    "source": "function test()
+{
+    /* comment */
+    # $m[] = 'declare';
+}",
+    "start": Position {
+      "column": 0,
+      "line": 1,
+      "offset": 0,
+    },
+  },
+}
+`;
+
 exports[`Test locations test #164 : expr must include ; 1`] = `
 Program {
   "children": [

test/snapshot/location.test.js

@@ -241,6 +241,22 @@ string";`,
     ).toMatchSnapshot();
   });
 
+  it("noop in comment-only body has correct start/end order", function () {
+    expect(
+      parser.parseEval(
+        `function test()
+{
+    /* comment */
+    # $m[] = 'declare';
+}`,
+        {
+          parser: { extractDoc: true },
+          ast: { withPositions: true, withSource: true },
+        },
+      ),
+    ).toMatchSnapshot();
+  });
+
   it("#164 : expr should avoid ?>", function () {
     expect(
       parser.parseCode("<?php $a = $b + 1 ?>", {