fix(cli-repl): improve explicit display of special characters in output MONGOSH-1910 (#2330)

Escape control characters in output strings if there's a reasonable chance that
their are (partially) coming from the server side, instead of printing them directly.
We keep printing them directly when it's reasonably possible that they are being used
intentionally for output control, e.g. when coming from `print()` or `console.log()`
statements.

Author: addaleax

packages/cli-repl/src/format-output.spec.ts

@@ -1,10 +1,14 @@
 /* eslint no-control-regex: 0 */
-import formatRaw from './format-output';
+import type { FormatOptions } from './format-output';
+import { formatOutput } from './format-output';
 import { expect } from 'chai';
 
 for (const colors of [false, true]) {
   describe(`formatOutput with 'colors' set to ${colors}`, function () {
-    const format = (value: any): string => formatRaw(value, { colors });
+    const format = (
+      value: { value: unknown; type?: string | null },
+      opts: Partial<FormatOptions> = {}
+    ): string => formatOutput(value, { colors, ...opts });
     const stripAnsiColors = colors
       ? (str: string): string => str.replace(/\x1B[[(?);]{0,2}(;?\d)*./g, '')
       : (str: string): string => str;
@@ -15,6 +19,31 @@ for (const colors of [false, true]) {
       });
     });
 
+    context(
+      'when the result is a string that only contains simple special characters',
+      function () {
+        it('returns the output', function () {
+          expect(format({ value: 'test\n\ttest' })).to.equal('test\n\ttest');
+        });
+      }
+    );
+
+    context(
+      'when the result is a string that contains special characters',
+      function () {
+        it('returns the output', function () {
+          expect(stripAnsiColors(format({ value: 'test\bfooo' }))).to.equal(
+            "'test\\bfooo'"
+          );
+        });
+        it('returns the raw value if control characters are allowed', function () {
+          expect(
+            format({ value: 'test\bfooo' }, { allowControlCharacters: true })
+          ).to.equal('test\bfooo');
+        });
+      }
+    );
+
     context('when the result is undefined', function () {
       it('returns the output', function () {
         expect(format({ value: undefined })).to.equal('');
@@ -253,10 +282,34 @@ for (const colors of [false, true]) {
           '\rError: Something went wrong\nCaused by: \n\rError: Something else went wrong'
         );
       });
+
+      it('escapes the message name if the error can be server-generated', function () {
+        const output = stripAnsiColors(
+          format({
+            value: Object.assign(new Error('foo\bbar.'), {
+              name: 'MongoServerError',
+            }),
+            type: 'Error',
+          })
+        );
+
+        expect(output).to.equal("\rMongoServerError: 'foo\\bbar.'");
+      });
+
+      it('does not escape the message name if the error is a generic one', function () {
+        const output = stripAnsiColors(
+          format({
+            value: Object.assign(new Error('foo\bbar.'), { name: 'FooError' }),
+            type: 'Error',
+          })
+        );
+
+        expect(output).to.equal('\rFooError: foo\bbar.');
+      });
     });
 
     context('when the result is ShowDatabasesResult', function () {
-      it('returns the help text', function () {
+      it('returns the database list', function () {
         const output = stripAnsiColors(
           format({
             value: [
@@ -265,25 +318,27 @@ for (const colors of [false, true]) {
               { name: 'supplies', sizeOnDisk: 2236416, empty: false },
               { name: 'test', sizeOnDisk: 5664768, empty: false },
               { name: 'test', sizeOnDisk: 599999768000, empty: false },
+              { name: 'ab\bdef', sizeOnDisk: 1234, empty: false },
             ],
             type: 'ShowDatabasesResult',
           })
         );
 
-        expect(output).to.equal(
+        expect(output.replace(/ +/g, ' ')).to.equal(
           `
-admin      44.00 KiB
-dxl         8.00 KiB
-supplies    2.13 MiB
-test        5.40 MiB
-test      558.79 GiB
+admin 44.00 KiB
+dxl 8.00 KiB
+supplies 2.13 MiB
+test 5.40 MiB
+test 558.79 GiB
+'ab\\bdef' 1.21 KiB
 `.trim()
         );
       });
     });
 
     context('when the result is ShowCollectionsResult', function () {
-      it('returns the help text', function () {
+      it('returns the collections list', function () {
         const output = stripAnsiColors(
           format({
             value: [
@@ -292,13 +347,19 @@ test      558.79 GiB
               { name: 'coll', badge: '' },
               { name: 'people_imported', badge: '[view]' },
               { name: 'cats', badge: '[time-series]' },
+              { name: 'cats\bcats', badge: '' },
             ],
             type: 'ShowCollectionsResult',
           })
         );
 
-        expect(output).to.equal(
-          'nested_documents\ndecimal128\ncoll\npeople_imported   [view]\ncats              [time-series]'
+        expect(output.replace(/ +/g, ' ')).to.equal(
+          'nested_documents\n' +
+            'decimal128\n' +
+            'coll\n' +
+            'people_imported [view]\n' +
+            'cats [time-series]\n' +
+            "'cats\\bcats'"
         );
       });
     });
@@ -319,15 +380,41 @@ test      558.79 GiB
           'c1\n{ metadata: 1 }\n---\nc2\n{ metadata: 2 }'
         );
       });
+      it('accounts for special characters and escapes them', function () {
+        const output = stripAnsiColors(
+          format({
+            value: {
+              ['c\b1']: { metadata: 1 },
+              c2: { metadata: 2 },
+            },
+            type: 'StatsResult',
+          })
+        );
+
+        expect(output).to.contain(
+          "'c\\b1'\n{ metadata: 1 }\n---\nc2\n{ metadata: 2 }"
+        );
+      });
     });
 
     context('when the result is ListCommandsResult', function () {
       it('returns the formatted list', function () {
         const output = stripAnsiColors(
           format({
             value: {
-              c1: { metadata1: 1, help: 'help1' },
-              c2: { metadata2: 2, help: 'help2' },
+              c1: { metadata1: true, help: 'help1' },
+              c2: {
+                metadata2: true,
+                help: 'help2',
+                apiVersions: [],
+                deprecatedApiVersions: [],
+              },
+              c3: {
+                metadata2: true,
+                help: 'help2',
+                apiVersions: ['1'],
+                deprecatedApiVersions: ['0'],
+              },
             },
             type: 'ListCommandsResult',
           })
@@ -543,5 +630,20 @@ test      558.79 GiB
         expect(output).to.equal('------\n   Header\n   foo\n   bar\n------\n');
       });
     });
+    it('returns a formatted banner with escaped special characters', function () {
+      const output = stripAnsiColors(
+        format({
+          value: {
+            header: 'Heade\br',
+            content: 'foo\bbar\n',
+          },
+          type: 'ShowBannerResult',
+        })
+      );
+
+      expect(output).to.equal(
+        "------\n   'Heade\\br'\n   'foo\\bbar\\n'\n------\n"
+      );
+    });
   });
 }