From 228897f6f6ff3ef888b0431aa3b75f8193a58157 Mon Sep 17 00:00:00 2001
From: Sean Milligan <sean.milligan@mongodb.com>
Date: Mon, 18 May 2026 12:12:26 -0700
Subject: [PATCH 1/8] test(NODE-7493): enable source maps for accurate unit
 test debugging

Pass --enable-source-maps to Node for all mocha configs so V8 resolves
inline source maps emitted by ts-node, making the debugger show correct
TypeScript file/line locations. Also add sourceMap: true to
test/tsconfig.json and ensure bundled test runs reset test/mongodb.ts
so stale VM-context state does not affect subsequent debug sessions.
---
 .mocharc.js                      |  5 ++-
 package.json                     |  4 +-
 test/manual/mocharc.js           |  5 ++-
 test/mocha_lambda.js             |  5 ++-
 test/mocha_mongodb.js            |  5 ++-
 test/tsconfig.json               |  3 +-
 test/unit/sourcemap_demo.test.ts | 74 ++++++++++++++++++++++++++++++++
 7 files changed, 94 insertions(+), 7 deletions(-)
 create mode 100644 test/unit/sourcemap_demo.test.ts

diff --git a/.mocharc.js b/.mocharc.js
index 13d28e27c2f..aa6841b1128 100644
--- a/.mocharc.js
+++ b/.mocharc.js
@@ -18,5 +18,8 @@ module.exports = {
   reporter: 'test/tools/reporter/mongodb_reporter.js',
   sort: true,
   color: true,
-  'node-option': Number(major) >= 23 ? ['no-experimental-strip-types'] : undefined
+  'node-option':
+    Number(major) >= 23
+      ? ['enable-source-maps', 'no-experimental-strip-types']
+      : ['enable-source-maps']
 };
diff --git a/package.json b/package.json
index 290e0e8c706..f2a338bf4fd 100644
--- a/package.json
+++ b/package.json
@@ -141,9 +141,9 @@
     "check:dts": "npm run build:bundle && node ./node_modules/typescript/bin/tsc --target es2023 --module commonjs --noEmit mongodb.d.ts && tsd",
     "check:search-indexes": "npm run build:bundle && nyc mocha --config test/mocha_mongodb.js test/manual/search-index-management.prose.test.ts",
     "check:test": "npm run build:bundle && nyc mocha --config test/mocha_mongodb.js test/integration",
-    "check:test-bundled": "MONGODB_BUNDLED=true npm run check:test",
+    "check:test-bundled": "MONGODB_BUNDLED=true npm run check:test; npm run build:runtime-barrel",
     "check:unit": "npm run build:bundle && nyc mocha test/unit",
-    "check:unit-bundled": "MONGODB_BUNDLED=true npm run check:unit",
+    "check:unit-bundled": "MONGODB_BUNDLED=true npm run check:unit; npm run build:runtime-barrel",
     "check:ts": "node ./node_modules/typescript/bin/tsc -v && node ./node_modules/typescript/bin/tsc --noEmit",
     "check:atlas": "npm run build:bundle && nyc mocha --config test/manual/mocharc.js test/manual/atlas_connectivity.test.ts",
     "check:drivers-atlas-testing": "npm run build:bundle && nyc mocha --config test/mocha_mongodb.js test/atlas/drivers_atlas_testing.test.ts",
diff --git a/test/manual/mocharc.js b/test/manual/mocharc.js
index 431bbf9a343..b948cb322a9 100644
--- a/test/manual/mocharc.js
+++ b/test/manual/mocharc.js
@@ -14,5 +14,8 @@ module.exports = {
   failZero: true,
   color: true,
   timeout: 10000,
-  'node-option': Number(major) >= 23 ? ['no-experimental-strip-types'] : undefined
+  'node-option':
+    Number(major) >= 23
+      ? ['enable-source-maps', 'no-experimental-strip-types']
+      : ['enable-source-maps']
 };
diff --git a/test/mocha_lambda.js b/test/mocha_lambda.js
index 962ab8a344b..9a87d2a2187 100644
--- a/test/mocha_lambda.js
+++ b/test/mocha_lambda.js
@@ -17,5 +17,8 @@ module.exports = {
   reporter: 'test/tools/reporter/mongodb_reporter.js',
   sort: true,
   color: true,
-  'node-option': Number(major) >= 23 ? ['no-experimental-strip-types'] : undefined
+  'node-option':
+    Number(major) >= 23
+      ? ['enable-source-maps', 'no-experimental-strip-types']
+      : ['enable-source-maps']
 };
diff --git a/test/mocha_mongodb.js b/test/mocha_mongodb.js
index d048520fea6..26bbca90479 100644
--- a/test/mocha_mongodb.js
+++ b/test/mocha_mongodb.js
@@ -31,5 +31,8 @@ module.exports = {
     'test/integration/node-specific/examples/transactions.test.js',
     'test/integration/node-specific/examples/versioned_api.js'
   ],
-  'node-option': Number(major) >= 23 ? ['no-experimental-strip-types'] : undefined
+  'node-option':
+    Number(major) >= 23
+      ? ['enable-source-maps', 'no-experimental-strip-types']
+      : ['enable-source-maps']
 };
diff --git a/test/tsconfig.json b/test/tsconfig.json
index 25dc395eec4..9750969223a 100644
--- a/test/tsconfig.json
+++ b/test/tsconfig.json
@@ -3,7 +3,8 @@
     "compilerOptions": {
         "strict": false,
         "allowJs": true,
-        "checkJs": false
+        "checkJs": false,
+        "sourceMap": true
     },
     "include": [
         "../node_modules/@types/mocha/index.d.ts",
diff --git a/test/unit/sourcemap_demo.test.ts b/test/unit/sourcemap_demo.test.ts
new file mode 100644
index 00000000000..acbcae43c4e
--- /dev/null
+++ b/test/unit/sourcemap_demo.test.ts
@@ -0,0 +1,74 @@
+// These import-type lines are completely erased by the TypeScript compiler
+// (no blank-line placeholder is left behind), so the compiled JS has fewer
+// lines than this source file.  That shifts every subsequent line upward in
+// the JS output.
+import type { Document as _Doc } from 'bson';
+import { expect } from 'chai';
+
+import type {
+  AbstractCursor as _AbC,
+  AggregationCursor as _AC,
+  ChangeStream as _CS,
+  ClientSession as _Sess,
+  Collection as _Col,
+  Db as _Db,
+  FindCursor as _FC,
+  GridFSBucket as _GB,
+  MongoClient as _MC
+} from '../../mongodb';
+
+// ─── This Error is created at line 31 in the TypeScript source. ───────────
+// The twelve `import type` lines above are erased without replacement, so
+// in the compiled JS this falls on line 31 − 12 = line 19.
+//
+// source-map-support patches Error.prepareStackTrace so `error.stack`
+// already shows the correct TS line.  The demo below DISABLES that patch
+// temporarily so we can see what V8 reports natively.
+//
+//   OLD commit (no --enable-source-maps): V8 says line 19  ← WRONG
+//   NEW commit (   --enable-source-maps): V8 says line 31  ← correct
+const TS_SOURCE_LINE = 31; // must match the line below
+const errorAtKnownLine = new Error('source-map probe'); // ← line 31
+
+/**
+ * Capture a raw V8 stack frame by temporarily removing
+ * source-map-support's prepareStackTrace override so we see exactly what
+ * V8 reports — with or without its own source-map awareness.
+ */
+function rawV8FrameOf(err: Error): {
+  file: string | null;
+  line: number | null;
+  col: number | null;
+} {
+  const saved = Error.prepareStackTrace;
+  // Null → V8 uses its built-in formatter (honours --enable-source-maps).
+  Error.prepareStackTrace = undefined as unknown as typeof Error.prepareStackTrace;
+  const raw = err.stack ?? ''; // triggers V8 formatting with no hook
+  Error.prepareStackTrace = saved;
+
+  // First "at …" line: "    at Object.<anonymous> (/abs/path/file.ts:LINE:COL)"
+  const match = raw.split('\n')[1]?.match(/\((.+):(\d+):(\d+)\)$/);
+  if (!match) return { file: null, line: null, col: null };
+  return { file: match[1], line: Number(match[2]), col: Number(match[3]) };
+}
+
+describe('Source map verification (NODE-7493)', function () {
+  it('V8 native stack frame reports correct TypeScript line number', function () {
+    const frame = rawV8FrameOf(errorAtKnownLine);
+
+    console.log('\n  ── raw V8 frame (prepareStackTrace bypassed) ──');
+    console.log(`  file : ${frame.file}`);
+    console.log(`  line : ${frame.line}  (TypeScript source line is ${TS_SOURCE_LINE})`);
+    console.log(`  col  : ${frame.col}`);
+    console.log(
+      `  ${frame.line === TS_SOURCE_LINE ? '✔ line matches TS source' : `✘ line ${frame.line} ≠ TS source line ${TS_SOURCE_LINE} — source maps not applied by V8`}`
+    );
+
+    expect(frame.line).to.equal(
+      TS_SOURCE_LINE,
+      `V8 reported line ${frame.line} but TypeScript source line is ${TS_SOURCE_LINE}. ` +
+        `This means --enable-source-maps is absent and V8 is reading the compiled-JS ` +
+        `line number instead of the original TypeScript line.`
+    );
+  });
+});

From 340248e4baa0d634b640c18e6f333b4ab13dc68a Mon Sep 17 00:00:00 2001
From: Sean Milligan <sean.milligan@mongodb.com>
Date: Wed, 3 Jun 2026 12:00:32 -0700
Subject: [PATCH 2/8] test(NODE-7493): enable source maps for accurate unit
 test debugging

---
 .mocharc.js                              |  1 -
 package-lock.json                        | 19 -------------------
 package.json                             |  3 +--
 test/mocha_mongodb.js                    |  1 -
 test/tools/runner/hooks/configuration.ts |  5 -----
 test/unit/sourcemap_demo.test.ts         | 11 ++++++-----
 6 files changed, 7 insertions(+), 33 deletions(-)

diff --git a/.mocharc.js b/.mocharc.js
index aa6841b1128..4177a964cbc 100644
--- a/.mocharc.js
+++ b/.mocharc.js
@@ -5,7 +5,6 @@ const [major] = process.versions.node.split('.');
 /** @type {import("mocha").MochaOptions} */
 module.exports = {
   require: [
-    'source-map-support/register',
     'ts-node/register',
     'test/tools/runner/throw_rejections.cjs',
     'test/tools/runner/chai_addons.ts',
diff --git a/package-lock.json b/package-lock.json
index d584873227e..35ae0cbcdf1 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -59,7 +59,6 @@
         "sinon-chai": "^3.7.0",
         "snappy": "^7.3.2",
         "socks": "^2.8.7",
-        "source-map-support": "^0.5.21",
         "ts-node": "^10.9.2",
         "tsd": "^0.33.0",
         "typescript": "5.8.3",
@@ -4403,13 +4402,6 @@
         "ieee754": "^1.1.13"
       }
     },
-    "node_modules/buffer-from": {
-      "version": "1.1.2",
-      "resolved": "https://registry.npmjs.org/buffer-from/-/buffer-from-1.1.2.tgz",
-      "integrity": "sha512-E+XQCRwSbaaiChtv6k6Dwgc+bx+Bs6vuKJHHl5kox/BaKbhiXzqQOwK4cO22yElGp2OCmjwVhT3HmxgyPGnJfQ==",
-      "dev": true,
-      "license": "MIT"
-    },
     "node_modules/bytes": {
       "version": "3.1.2",
       "resolved": "https://registry.npmjs.org/bytes/-/bytes-3.1.2.tgz",
@@ -9480,17 +9472,6 @@
         "node": ">=0.10.0"
       }
     },
-    "node_modules/source-map-support": {
-      "version": "0.5.21",
-      "resolved": "https://registry.npmjs.org/source-map-support/-/source-map-support-0.5.21.tgz",
-      "integrity": "sha512-uBHU3L3czsIyYXKX88fdrGovxdSCoTGDRZ6SYXtSRxLZUzHg5P/66Ht6uoUlHu9EZod+inXhKo3qQgwXUT/y1w==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "buffer-from": "^1.0.0",
-        "source-map": "^0.6.0"
-      }
-    },
     "node_modules/sparse-bitfield": {
       "version": "3.0.3",
       "resolved": "https://registry.npmjs.org/sparse-bitfield/-/sparse-bitfield-3.0.3.tgz",
diff --git a/package.json b/package.json
index f2a338bf4fd..ae05f26c7fb 100644
--- a/package.json
+++ b/package.json
@@ -106,7 +106,6 @@
     "sinon-chai": "^3.7.0",
     "snappy": "^7.3.2",
     "socks": "^2.8.7",
-    "source-map-support": "^0.5.21",
     "ts-node": "^10.9.2",
     "tsd": "^0.33.0",
     "typescript": "5.8.3",
@@ -160,7 +159,7 @@
     "build:bundle": "npm run bundle:driver && npm run bundle:types && npm run build:runtime-barrel",
     "build:runtime-barrel": "node etc/build-runtime-barrel.mjs",
     "bundle:driver": "node etc/bundle-driver.mjs",
-    "bundle:types": "npx tsc --project ./tsconfig.json --declaration --emitDeclarationOnly --declarationDir test/tools/runner/bundle/types",
+    "bundle:types": "node ./node_modules/typescript/bin/tsc --project ./tsconfig.json --declaration --emitDeclarationOnly --declarationDir test/tools/runner/bundle/types",
     "fix:eslint": "npm run check:eslint -- --fix",
     "prepare": "node etc/prepare.js",
     "preview:docs": "ts-node etc/docs/preview.ts",
diff --git a/test/mocha_mongodb.js b/test/mocha_mongodb.js
index 26bbca90479..afbf8224571 100644
--- a/test/mocha_mongodb.js
+++ b/test/mocha_mongodb.js
@@ -6,7 +6,6 @@ const [major] = process.versions.node.split('.');
 /** @type {import("mocha").MochaOptions} */
 module.exports = {
   require: [
-    'source-map-support/register',
     'ts-node/register',
     'test/tools/runner/throw_rejections.cjs',
     'test/tools/runner/chai_addons.ts',
diff --git a/test/tools/runner/hooks/configuration.ts b/test/tools/runner/hooks/configuration.ts
index 0220d81fb9b..db6a50344b2 100644
--- a/test/tools/runner/hooks/configuration.ts
+++ b/test/tools/runner/hooks/configuration.ts
@@ -1,10 +1,5 @@
 /* eslint-disable simple-import-sort/imports */
 
-// eslint-disable-next-line @typescript-eslint/no-require-imports
-require('source-map-support').install({
-  hookRequire: true
-});
-
 import * as process from 'process';
 import * as os from 'os';
 
diff --git a/test/unit/sourcemap_demo.test.ts b/test/unit/sourcemap_demo.test.ts
index acbcae43c4e..f2d8982d704 100644
--- a/test/unit/sourcemap_demo.test.ts
+++ b/test/unit/sourcemap_demo.test.ts
@@ -21,9 +21,9 @@ import type {
 // The twelve `import type` lines above are erased without replacement, so
 // in the compiled JS this falls on line 31 − 12 = line 19.
 //
-// source-map-support patches Error.prepareStackTrace so `error.stack`
-// already shows the correct TS line.  The demo below DISABLES that patch
-// temporarily so we can see what V8 reports natively.
+// ts-node's bundled `@cspotcode/source-map-support` patches
+// Error.prepareStackTrace so `error.stack` already shows the correct TS
+// line.  The demo below DISABLES that patch to see what V8 reports natively.
 //
 //   OLD commit (no --enable-source-maps): V8 says line 19  ← WRONG
 //   NEW commit (   --enable-source-maps): V8 says line 31  ← correct
@@ -32,8 +32,9 @@ const errorAtKnownLine = new Error('source-map probe'); // ← line 31
 
 /**
  * Capture a raw V8 stack frame by temporarily removing
- * source-map-support's prepareStackTrace override so we see exactly what
- * V8 reports — with or without its own source-map awareness.
+ * `@cspotcode/source-map-support`'s prepareStackTrace override (installed
+ * by ts-node) so we see exactly what V8 reports — with or without its own
+ * source-map awareness.
  */
 function rawV8FrameOf(err: Error): {
   file: string | null;

From d5fbddd9361b3a95424c008c62d605f5a39cfa0a Mon Sep 17 00:00:00 2001
From: Sean Milligan <sean.milligan@mongodb.com>
Date: Wed, 3 Jun 2026 12:51:06 -0700
Subject: [PATCH 3/8] Rename source map test

---
 .../{sourcemap_demo.test.ts => source_map.test.ts}     | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)
 rename test/unit/{sourcemap_demo.test.ts => source_map.test.ts} (88%)

diff --git a/test/unit/sourcemap_demo.test.ts b/test/unit/source_map.test.ts
similarity index 88%
rename from test/unit/sourcemap_demo.test.ts
rename to test/unit/source_map.test.ts
index f2d8982d704..d3908c31ec6 100644
--- a/test/unit/sourcemap_demo.test.ts
+++ b/test/unit/source_map.test.ts
@@ -23,7 +23,7 @@ import type {
 //
 // ts-node's bundled `@cspotcode/source-map-support` patches
 // Error.prepareStackTrace so `error.stack` already shows the correct TS
-// line.  The demo below DISABLES that patch to see what V8 reports natively.
+// line. We DISABLE that patch to see what V8 reports natively.
 //
 //   OLD commit (no --enable-source-maps): V8 says line 19  ← WRONG
 //   NEW commit (   --enable-source-maps): V8 says line 31  ← correct
@@ -53,8 +53,8 @@ function rawV8FrameOf(err: Error): {
   return { file: match[1], line: Number(match[2]), col: Number(match[3]) };
 }
 
-describe('Source map verification (NODE-7493)', function () {
-  it('V8 native stack frame reports correct TypeScript line number', function () {
+describe('Source maps', function () {
+  it('report the collect line number when enabled', function () {
     const frame = rawV8FrameOf(errorAtKnownLine);
 
     console.log('\n  ── raw V8 frame (prepareStackTrace bypassed) ──');
@@ -68,8 +68,8 @@ describe('Source map verification (NODE-7493)', function () {
     expect(frame.line).to.equal(
       TS_SOURCE_LINE,
       `V8 reported line ${frame.line} but TypeScript source line is ${TS_SOURCE_LINE}. ` +
-        `This means --enable-source-maps is absent and V8 is reading the compiled-JS ` +
-        `line number instead of the original TypeScript line.`
+      `This means --enable-source-maps is absent and V8 is reading the compiled-JS ` +
+      `line number instead of the original TypeScript line.`
     );
   });
 });

From 130a107f14f8b300640ba6ce8a11e53d3352d7ae Mon Sep 17 00:00:00 2001
From: Sean Milligan <sean.milligan@mongodb.com>
Date: Thu, 4 Jun 2026 08:15:18 -0700
Subject: [PATCH 4/8] Remove building the barrel from check:unit-bundled and
 check:test-bundled

---
 package.json | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/package.json b/package.json
index ae05f26c7fb..a30b8e1d292 100644
--- a/package.json
+++ b/package.json
@@ -140,9 +140,9 @@
     "check:dts": "npm run build:bundle && node ./node_modules/typescript/bin/tsc --target es2023 --module commonjs --noEmit mongodb.d.ts && tsd",
     "check:search-indexes": "npm run build:bundle && nyc mocha --config test/mocha_mongodb.js test/manual/search-index-management.prose.test.ts",
     "check:test": "npm run build:bundle && nyc mocha --config test/mocha_mongodb.js test/integration",
-    "check:test-bundled": "MONGODB_BUNDLED=true npm run check:test; npm run build:runtime-barrel",
+    "check:test-bundled": "MONGODB_BUNDLED=true npm run check:test",
     "check:unit": "npm run build:bundle && nyc mocha test/unit",
-    "check:unit-bundled": "MONGODB_BUNDLED=true npm run check:unit; npm run build:runtime-barrel",
+    "check:unit-bundled": "MONGODB_BUNDLED=true npm run check:unit",
     "check:ts": "node ./node_modules/typescript/bin/tsc -v && node ./node_modules/typescript/bin/tsc --noEmit",
     "check:atlas": "npm run build:bundle && nyc mocha --config test/manual/mocharc.js test/manual/atlas_connectivity.test.ts",
     "check:drivers-atlas-testing": "npm run build:bundle && nyc mocha --config test/mocha_mongodb.js test/atlas/drivers_atlas_testing.test.ts",

From 54b538cf463ad1933e143e06bf56f43914a89190 Mon Sep 17 00:00:00 2001
From: Sean Milligan <sean.milligan@mongodb.com>
Date: Thu, 4 Jun 2026 08:16:59 -0700
Subject: [PATCH 5/8] fix: typo

---
 test/unit/source_map.test.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/unit/source_map.test.ts b/test/unit/source_map.test.ts
index d3908c31ec6..c49d326b7e7 100644
--- a/test/unit/source_map.test.ts
+++ b/test/unit/source_map.test.ts
@@ -54,7 +54,7 @@ function rawV8FrameOf(err: Error): {
 }
 
 describe('Source maps', function () {
-  it('report the collect line number when enabled', function () {
+  it('report the correct line number when enabled', function () {
     const frame = rawV8FrameOf(errorAtKnownLine);
 
     console.log('\n  ── raw V8 frame (prepareStackTrace bypassed) ──');

From d017df91fd2fb462238dc520a1b85b7f06b0111d Mon Sep 17 00:00:00 2001
From: Sean Milligan <sean.milligan@mongodb.com>
Date: Thu, 4 Jun 2026 08:26:15 -0700
Subject: [PATCH 6/8] Guard console logs with VERBOSE variable

Use `VERBOSE=1 npm run check:unit -- -g "Source maps"` to run
---
 test/unit/source_map.test.ts | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/test/unit/source_map.test.ts b/test/unit/source_map.test.ts
index c49d326b7e7..acae1aa7d28 100644
--- a/test/unit/source_map.test.ts
+++ b/test/unit/source_map.test.ts
@@ -57,14 +57,15 @@ describe('Source maps', function () {
   it('report the correct line number when enabled', function () {
     const frame = rawV8FrameOf(errorAtKnownLine);
 
-    console.log('\n  ── raw V8 frame (prepareStackTrace bypassed) ──');
-    console.log(`  file : ${frame.file}`);
-    console.log(`  line : ${frame.line}  (TypeScript source line is ${TS_SOURCE_LINE})`);
-    console.log(`  col  : ${frame.col}`);
-    console.log(
-      `  ${frame.line === TS_SOURCE_LINE ? '✔ line matches TS source' : `✘ line ${frame.line} ≠ TS source line ${TS_SOURCE_LINE} — source maps not applied by V8`}`
-    );
-
+    if (process.env.VERBOSE) {
+      console.error('\n  ── raw V8 frame (prepareStackTrace bypassed) ──');
+      console.error(`  file : ${frame.file}`);
+      console.error(`  line : ${frame.line}  (TypeScript source line is ${TS_SOURCE_LINE})`);
+      console.error(`  col  : ${frame.col}`);
+      console.error(
+        `  ${frame.line === TS_SOURCE_LINE ? '✔ line matches TS source' : `✘ line ${frame.line} ≠ TS source line ${TS_SOURCE_LINE} — source maps not applied by V8`}`
+      );
+    }
     expect(frame.line).to.equal(
       TS_SOURCE_LINE,
       `V8 reported line ${frame.line} but TypeScript source line is ${TS_SOURCE_LINE}. ` +

From f0ab6854a82af1574e730a4d2c55391698f413e8 Mon Sep 17 00:00:00 2001
From: Sean Milligan <sean.milligan@mongodb.com>
Date: Fri, 5 Jun 2026 14:15:26 -0700
Subject: [PATCH 7/8] wip

---
 .mocharc.js                              |  1 +
 package-lock.json                        | 20 +++++++++++++++++++-
 package.json                             |  1 +
 test/manual/mocharc.js                   |  1 +
 test/mocha_mongodb.js                    |  1 +
 test/tools/runner/hooks/configuration.ts |  5 +++++
 6 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/.mocharc.js b/.mocharc.js
index 4177a964cbc..aa6841b1128 100644
--- a/.mocharc.js
+++ b/.mocharc.js
@@ -5,6 +5,7 @@ const [major] = process.versions.node.split('.');
 /** @type {import("mocha").MochaOptions} */
 module.exports = {
   require: [
+    'source-map-support/register',
     'ts-node/register',
     'test/tools/runner/throw_rejections.cjs',
     'test/tools/runner/chai_addons.ts',
diff --git a/package-lock.json b/package-lock.json
index 35ae0cbcdf1..3dbae71a69b 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -34,7 +34,6 @@
         "@typescript-eslint/eslint-plugin": "^8.46.3",
         "@typescript-eslint/parser": "^8.31.1",
         "aws4": "^1.13.2",
-        "baseline-browser-mapping": "^2.10.0",
         "chai": "^4.4.1",
         "chai-subset": "^1.6.0",
         "chalk": "^4.1.2",
@@ -59,6 +58,7 @@
         "sinon-chai": "^3.7.0",
         "snappy": "^7.3.2",
         "socks": "^2.8.7",
+        "source-map-support": "^0.5.21",
         "ts-node": "^10.9.2",
         "tsd": "^0.33.0",
         "typescript": "5.8.3",
@@ -4402,6 +4402,13 @@
         "ieee754": "^1.1.13"
       }
     },
+    "node_modules/buffer-from": {
+      "version": "1.1.2",
+      "resolved": "https://registry.npmjs.org/buffer-from/-/buffer-from-1.1.2.tgz",
+      "integrity": "sha512-E+XQCRwSbaaiChtv6k6Dwgc+bx+Bs6vuKJHHl5kox/BaKbhiXzqQOwK4cO22yElGp2OCmjwVhT3HmxgyPGnJfQ==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/bytes": {
       "version": "3.1.2",
       "resolved": "https://registry.npmjs.org/bytes/-/bytes-3.1.2.tgz",
@@ -9472,6 +9479,17 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/source-map-support": {
+      "version": "0.5.21",
+      "resolved": "https://registry.npmjs.org/source-map-support/-/source-map-support-0.5.21.tgz",
+      "integrity": "sha512-uBHU3L3czsIyYXKX88fdrGovxdSCoTGDRZ6SYXtSRxLZUzHg5P/66Ht6uoUlHu9EZod+inXhKo3qQgwXUT/y1w==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "buffer-from": "^1.0.0",
+        "source-map": "^0.6.0"
+      }
+    },
     "node_modules/sparse-bitfield": {
       "version": "3.0.3",
       "resolved": "https://registry.npmjs.org/sparse-bitfield/-/sparse-bitfield-3.0.3.tgz",
diff --git a/package.json b/package.json
index a30b8e1d292..dd6f7558d69 100644
--- a/package.json
+++ b/package.json
@@ -106,6 +106,7 @@
     "sinon-chai": "^3.7.0",
     "snappy": "^7.3.2",
     "socks": "^2.8.7",
+    "source-map-support": "^0.5.21",
     "ts-node": "^10.9.2",
     "tsd": "^0.33.0",
     "typescript": "5.8.3",
diff --git a/test/manual/mocharc.js b/test/manual/mocharc.js
index b948cb322a9..24e435b353b 100644
--- a/test/manual/mocharc.js
+++ b/test/manual/mocharc.js
@@ -6,6 +6,7 @@ const [major] = process.versions.node.split('.');
 /** @type {import("mocha").MochaOptions} */
 module.exports = {
   require: [
+    'source-map-support/register',
     'ts-node/register',
     'test/tools/runner/throw_rejections.cjs',
     'test/tools/runner/chai_addons.ts'
diff --git a/test/mocha_mongodb.js b/test/mocha_mongodb.js
index afbf8224571..26bbca90479 100644
--- a/test/mocha_mongodb.js
+++ b/test/mocha_mongodb.js
@@ -6,6 +6,7 @@ const [major] = process.versions.node.split('.');
 /** @type {import("mocha").MochaOptions} */
 module.exports = {
   require: [
+    'source-map-support/register',
     'ts-node/register',
     'test/tools/runner/throw_rejections.cjs',
     'test/tools/runner/chai_addons.ts',
diff --git a/test/tools/runner/hooks/configuration.ts b/test/tools/runner/hooks/configuration.ts
index db6a50344b2..0220d81fb9b 100644
--- a/test/tools/runner/hooks/configuration.ts
+++ b/test/tools/runner/hooks/configuration.ts
@@ -1,5 +1,10 @@
 /* eslint-disable simple-import-sort/imports */
 
+// eslint-disable-next-line @typescript-eslint/no-require-imports
+require('source-map-support').install({
+  hookRequire: true
+});
+
 import * as process from 'process';
 import * as os from 'os';
 

From a1be2a88ec100528a9737560ebdfb836ee3f03b0 Mon Sep 17 00:00:00 2001
From: Sean Milligan <sean.milligan@mongodb.com>
Date: Fri, 5 Jun 2026 14:41:22 -0700
Subject: [PATCH 8/8] wip

---
 .mocharc.js                              | 2 +-
 test/manual/mocharc.js                   | 2 +-
 test/mocha_mongodb.js                    | 2 +-
 test/tools/runner/hooks/configuration.ts | 5 -----
 test/tools/runner/source_map.cjs         | 4 ++++
 5 files changed, 7 insertions(+), 8 deletions(-)
 create mode 100644 test/tools/runner/source_map.cjs

diff --git a/.mocharc.js b/.mocharc.js
index aa6841b1128..6ff6b3c09e3 100644
--- a/.mocharc.js
+++ b/.mocharc.js
@@ -5,8 +5,8 @@ const [major] = process.versions.node.split('.');
 /** @type {import("mocha").MochaOptions} */
 module.exports = {
   require: [
-    'source-map-support/register',
     'ts-node/register',
+    'test/tools/runner/source_map.cjs',
     'test/tools/runner/throw_rejections.cjs',
     'test/tools/runner/chai_addons.ts',
     'test/tools/runner/ee_checker.ts'
diff --git a/test/manual/mocharc.js b/test/manual/mocharc.js
index 24e435b353b..79ebc4da639 100644
--- a/test/manual/mocharc.js
+++ b/test/manual/mocharc.js
@@ -6,8 +6,8 @@ const [major] = process.versions.node.split('.');
 /** @type {import("mocha").MochaOptions} */
 module.exports = {
   require: [
-    'source-map-support/register',
     'ts-node/register',
+    'test/tools/runner/source_map.cjs',
     'test/tools/runner/throw_rejections.cjs',
     'test/tools/runner/chai_addons.ts'
   ],
diff --git a/test/mocha_mongodb.js b/test/mocha_mongodb.js
index 26bbca90479..c86bf54f9a5 100644
--- a/test/mocha_mongodb.js
+++ b/test/mocha_mongodb.js
@@ -6,8 +6,8 @@ const [major] = process.versions.node.split('.');
 /** @type {import("mocha").MochaOptions} */
 module.exports = {
   require: [
-    'source-map-support/register',
     'ts-node/register',
+    'test/tools/runner/source_map.cjs',
     'test/tools/runner/throw_rejections.cjs',
     'test/tools/runner/chai_addons.ts',
     'test/tools/runner/ee_checker.ts',
diff --git a/test/tools/runner/hooks/configuration.ts b/test/tools/runner/hooks/configuration.ts
index 0220d81fb9b..db6a50344b2 100644
--- a/test/tools/runner/hooks/configuration.ts
+++ b/test/tools/runner/hooks/configuration.ts
@@ -1,10 +1,5 @@
 /* eslint-disable simple-import-sort/imports */
 
-// eslint-disable-next-line @typescript-eslint/no-require-imports
-require('source-map-support').install({
-  hookRequire: true
-});
-
 import * as process from 'process';
 import * as os from 'os';
 
diff --git a/test/tools/runner/source_map.cjs b/test/tools/runner/source_map.cjs
new file mode 100644
index 00000000000..2b8bab0621e
--- /dev/null
+++ b/test/tools/runner/source_map.cjs
@@ -0,0 +1,4 @@
+// eslint-disable-next-line @typescript-eslint/no-require-imports
+require('source-map-support').install({
+    hookRequire: true
+});