fix: Avoid internally generating negative source maps columns (#15719)

babel · Jul 5, 2023 · 4986833 · 4986833
1 parent abb5a7c
commit 4986833
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Showing 6 changed files with 75 additions and 26 deletions.
diff --git a/packages/babel-generator/package.json b/packages/babel-generator/package.json
@@ -27,6 +27,7 @@
   "devDependencies": {
     "@babel/helper-fixtures": "workspace:^",
     "@babel/parser": "workspace:^",
+    "@jridgewell/sourcemap-codec": "^1.4.15",
     "@types/jsesc": "^2.5.0",
     "charcodes": "^0.2.0"
   },

diff --git a/packages/babel-generator/src/buffer.ts b/packages/babel-generator/src/buffer.ts
@@ -443,18 +443,17 @@ export default class Buffer {
 
     // Since this is called extremely often, we re-use the same _sourcePosition
     // object for the whole lifetime of the buffer.
-    this._normalizePosition(prop, loc, 0, 0);
+    this._normalizePosition(prop, loc, 0);
   }
 
   sourceWithOffset(
     prop: "start" | "end",
     loc: Loc | undefined,
-    lineOffset: number,
     columnOffset: number,
   ): void {
     if (!this._map) return;
 
-    this._normalizePosition(prop, loc, lineOffset, columnOffset);
+    this._normalizePosition(prop, loc, columnOffset);
   }
 
   /**
@@ -469,18 +468,14 @@ export default class Buffer {
     cb();
   }
 
-  _normalizePosition(
-    prop: "start" | "end",
-    loc: Loc,
-    lineOffset: number,
-    columnOffset: number,
-  ) {
+  _normalizePosition(prop: "start" | "end", loc: Loc, columnOffset: number) {
     const pos = loc[prop];
     const target = this._sourcePosition;
 
     if (pos) {
-      target.line = pos.line + lineOffset;
-      target.column = pos.column + columnOffset;
+      target.line = pos.line;
+      // TODO: Fix https://github.com/babel/babel/issues/15712 in downstream
+      target.column = Math.max(pos.column + columnOffset, 0);
       target.filename = loc.filename;
     }
   }

diff --git a/packages/babel-generator/src/generators/types.ts b/packages/babel-generator/src/generators/types.ts
@@ -33,7 +33,7 @@ export function ObjectExpression(this: Printer, node: t.ObjectExpression) {
     this.space();
   }
 
-  this.sourceWithOffset("end", node.loc, 0, -1);
+  this.sourceWithOffset("end", node.loc, -1);
 
   this.token("}");
 }

diff --git a/packages/babel-generator/src/printer.ts b/packages/babel-generator/src/printer.ts
@@ -185,12 +185,12 @@ class Printer {
     if (this.format.minified) {
       this._buf.removeLastSemicolon();
     }
-    this.sourceWithOffset("end", node.loc, 0, -1);
+    this.sourceWithOffset("end", node.loc, -1);
     this.token("}");
   }
 
   rightParens(node: t.Node): void {
-    this.sourceWithOffset("end", node.loc, 0, -1);
+    this.sourceWithOffset("end", node.loc, -1);
     this.token(")");
   }
 
@@ -365,14 +365,13 @@ class Printer {
   sourceWithOffset(
     prop: "start" | "end",
     loc: Loc | undefined,
-    lineOffset: number,
     columnOffset: number,
   ): void {
     if (!loc) return;
 
     this._catchUp(prop, loc);
 
-    this._buf.sourceWithOffset(prop, loc, lineOffset, columnOffset);
+    this._buf.sourceWithOffset(prop, loc, columnOffset);
   }
 
   withSource(

diff --git a/packages/babel-generator/test/index.js b/packages/babel-generator/test/index.js
@@ -1,14 +1,17 @@
-import { parse } from "@babel/parser";
+import { parse, parseExpression } from "@babel/parser";
 import * as t from "@babel/types";
 import fs from "fs";
 import path from "path";
 import fixtures from "@babel/helper-fixtures";
 import { TraceMap, originalPositionFor } from "@jridgewell/trace-mapping";
-import { fileURLToPath } from "url";
+import { commonJS } from "$repo-utils";
+import { encode } from "@jridgewell/sourcemap-codec";
 
 import _generate, { CodeGenerator } from "../lib/index.js";
 const generate = _generate.default || _generate;
 
+const { __dirname } = commonJS(import.meta.url);
+
 describe("generation", function () {
   it("multiple sources", function () {
     const sources = {
@@ -914,6 +917,61 @@ describe("generation", function () {
       }
     `);
   });
+
+  it("should not throw when loc.column === 0 with inputSourceMap", () => {
+    const ast = parseExpression("a(\n)");
+
+    ast.loc.end.column = 0;
+
+    expect(
+      generate(ast, {
+        sourceMaps: true,
+        inputSourceMap: {
+          version: 3,
+          names: [],
+          sources: ["input.js"],
+          // [ generatedCodeColumn, sourceIndex, sourceCodeLine, sourceCodeColumn, nameIndex ]
+          mappings: encode([[0, 0, 1, 0]]),
+        },
+      }).rawMappings,
+    ).toMatchInlineSnapshot(`
+      Array [
+        Object {
+          "generated": Object {
+            "column": 0,
+            "line": 1,
+          },
+          "name": "a",
+          "original": Object {
+            "column": 0,
+            "line": 1,
+          },
+          "source": "input.js",
+        },
+        Object {
+          "generated": Object {
+            "column": 1,
+            "line": 1,
+          },
+          "name": undefined,
+          "original": Object {
+            "column": 0,
+            "line": 1,
+          },
+          "source": "input.js",
+        },
+        Object {
+          "generated": Object {
+            "column": 2,
+            "line": 1,
+          },
+          "name": undefined,
+          "original": undefined,
+          "source": undefined,
+        },
+      ]
+    `);
+  });
 });
 
 describe("programmatic generation", function () {
@@ -1435,9 +1493,7 @@ describe("CodeGenerator", function () {
   });
 });
 
-const suites = (fixtures.default || fixtures)(
-  path.join(path.dirname(fileURLToPath(import.meta.url)), "fixtures"),
-);
+const suites = (fixtures.default || fixtures)(path.join(__dirname, "fixtures"));
 
 afterEach(() => {
   jest.restoreAllMocks();
@@ -1467,10 +1523,7 @@ suites.forEach(function (testSuite) {
             };
             const actualAst = parse(actualCode, parserOpts);
             const options = {
-              sourceFileName: path.relative(
-                path.dirname(fileURLToPath(import.meta.url)),
-                actual.loc,
-              ),
+              sourceFileName: path.relative(__dirname, actual.loc),
               ...task.options,
               sourceMaps: task.sourceMap ? true : task.options.sourceMaps,
             };

diff --git a/yarn.lock b/yarn.lock
@@ -498,6 +498,7 @@ __metadata:
     "@babel/parser": "workspace:^"
     "@babel/types": "workspace:^"
     "@jridgewell/gen-mapping": ^0.3.2
+    "@jridgewell/sourcemap-codec": ^1.4.15
     "@jridgewell/trace-mapping": ^0.3.17
     "@types/jsesc": ^2.5.0
     charcodes: ^0.2.0
@@ -4416,7 +4417,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@jridgewell/sourcemap-codec@npm:^1.4.10, @jridgewell/sourcemap-codec@npm:^1.4.13":
+"@jridgewell/sourcemap-codec@npm:^1.4.10, @jridgewell/sourcemap-codec@npm:^1.4.13, @jridgewell/sourcemap-codec@npm:^1.4.15":
   version: 1.4.15
   resolution: "@jridgewell/sourcemap-codec@npm:1.4.15"
   checksum: b881c7e503db3fc7f3c1f35a1dd2655a188cc51a3612d76efc8a6eb74728bef5606e6758ee77423e564092b4a518aba569bbb21c9bac5ab7a35b0c6ae7e344c8