fix: improve field name escaping for dots and slashes

Author: mayank1513

.changeset/fix-field-escaping.md

@@ -0,0 +1,7 @@
+---
+"git-json-resolver": patch
+---
+
+Fix field name escaping for dots and slashes in object keys
+
+Improves handling of complex field names containing dots and slashes (e.g., scoped package names like `@scope/package` or URLs) by introducing proper escape sequences and updating the matcher logic to handle these cases consistently across all matcher implementations.

lib/src/matcher.test.ts

@@ -1,5 +1,5 @@
 import { describe, it, expect } from "vitest";
-import { basicMatcher, loadMatcher } from "./matcher";
+import { basicMatcher, ESCAPED_DOT, loadMatcher, ESCAPED_SLASH } from "./matcher";
 
 for (const matcherName of ["basicMatcher", "micromatch", "picomatch"] as const) {
   describe(matcherName, async () => {
@@ -68,6 +68,20 @@ for (const matcherName of ["basicMatcher", "micromatch", "picomatch"] as const)
       expect(matcher.isMatch("src", ["!src"])).toBe(false);
       expect(matcher.isMatch("other", ["!src"])).toBe(true);
     });
+
+    it("handles object fields with dots and slashes", () => {
+      // Test scoped package names like @m2d/core
+      expect(matcher.isMatch(`deps.@m2d${ESCAPED_SLASH}core`, ["deps.*"])).toBe(true);
+      expect(matcher.isMatch(`deps.@m2d${ESCAPED_SLASH}core`, ["deps.@m2d\\/core"])).toBe(true);
+
+      // Test field names with both dots and slashes
+      expect(
+        matcher.isMatch(
+          `urls.https:${ESCAPED_SLASH}${ESCAPED_SLASH}api${ESCAPED_DOT}example${ESCAPED_DOT}com${ESCAPED_SLASH}v1`,
+          ["urls.*"],
+        ),
+      ).toBe(true);
+    });
   });
 }
 
@@ -87,4 +101,25 @@ describe("loadMatcher", () => {
   it("throws on unknown matcher", async () => {
     await expect(() => loadMatcher("invalid" as any)).rejects.toThrow(/Unknown matcher/);
   });
+
+  it("handles complex field names consistently across matchers", async () => {
+    const testCases = [
+      { field: `deps.@m2d${ESCAPED_SLASH}core`, pattern: "deps.*", expected: true },
+      {
+        field: `urls.https:${ESCAPED_SLASH}${ESCAPED_SLASH}api${ESCAPED_DOT}example${ESCAPED_DOT}com${ESCAPED_SLASH}v1`,
+        pattern: "urls.*",
+        expected: true,
+      },
+    ];
+
+    for (const { field, pattern, expected } of testCases) {
+      expect(basicMatcher.isMatch(field, [pattern])).toBe(expected);
+
+      const mm = await loadMatcher("micromatch");
+      expect(mm.isMatch(field, [pattern])).toBe(expected);
+
+      const pm = await loadMatcher("picomatch");
+      expect(pm.isMatch(field, [pattern])).toBe(expected);
+    }
+  });
 });

lib/src/matcher.ts

@@ -1,3 +1,8 @@
+/** Escape sequence for literal dots in field names */
+export const ESCAPED_DOT = "\u0000";
+/** Escape sequence for literal slashes in field names */
+export const ESCAPED_SLASH = "\u0001";
+
 /**
  * Matcher abstraction + adapters for micromatch/picomatch (optional).
  *
@@ -9,7 +14,6 @@
  *
  * Micromatch/Picomatch can be loaded at runtime as optional peers.
  */
-
 export interface Matcher {
   /**
    * Returns true if `str` matches at least one of the provided glob `patterns`.
@@ -40,7 +44,7 @@ export const basicMatcher: Matcher = {
 
 export const loadMatcher = async (name: "micromatch" | "picomatch"): Promise<Matcher> => {
   if (name === "micromatch") {
-    let micromatch: any;
+    let micromatch;
     try {
       micromatch = await import("micromatch");
     } catch {
@@ -63,7 +67,7 @@ export const loadMatcher = async (name: "micromatch" | "picomatch"): Promise<Mat
   }
 
   if (name === "picomatch") {
-    let picomatch: any;
+    let picomatch;
     try {
       picomatch = (await import("picomatch")).default;
     } catch {
@@ -95,27 +99,13 @@ export const loadMatcher = async (name: "micromatch" | "picomatch"): Promise<Mat
  * Convert a pattern/field path into internal form (`/` separated).
  * - Unescaped `.` → `/`
  * - Unescaped `/` → `/`
- * - Escaped `\.` → `.`
- * - Escaped `\/` → `/`
+ * - Escaped `\.` → `ESCAPED_DOT`
+ * - Escaped `\/` → `ESCAPED_SLASH`
  */
-const toInternal = (input: string): string => {
-  let out = "";
-  let escaped = false;
-  for (const ch of input) {
-    if (escaped) {
-      out += ch; // take literally
-      escaped = false;
-    } else if (ch === "\\") {
-      escaped = true;
-      out += "\\"; // preserve backslash for downstream escape handling
-    } else if (ch === ".") {
-      out += "/"; // dot becomes slash
-    } else {
-      out += ch;
-    }
-  }
-  return out;
-};
+const toInternal = (input: string): string =>
+  input.replace(/\\[./]|\./g, match =>
+    match === "\\." ? ESCAPED_DOT : match === "\\/" ? ESCAPED_SLASH : "/",
+  );
 
 /**
  * Splits a glob pattern into dot-separated segments, honoring backslash escaping.

lib/src/merger.ts

@@ -1,4 +1,5 @@
 import { createLogger } from "./logger";
+import { ESCAPED_DOT, ESCAPED_SLASH } from "./matcher";
 import { NormalizedConfig } from "./normalizer";
 import { resolveStrategies } from "./strategy-resolver";
 import { StrategyFn, StrategyResult, StrategyStatus } from "./types";
@@ -114,11 +115,12 @@ export const BuiltInStrategies = {
       const allKeys = new Set([...Object.keys(ours), ...Object.keys(theirs)]);
       const result: Record<string, unknown> = {};
       for (const key of allKeys) {
+        const escapedKey = key.replace(/\./g, ESCAPED_DOT).replace(/\\/g, ESCAPED_SLASH);
         result[key] = await mergeObject({
           ours: (ours as Record<string, unknown>)[key],
           theirs: (theirs as Record<string, unknown>)[key],
           base: isPlainObject(base) ? (base as Record<string, unknown>)[key] : undefined,
-          path: path ? `${path}.${key}` : key,
+          path: path ? `${path}.${escapedKey}` : escapedKey,
           filePath,
           ctx,
           conflicts,