feat(autocomplete): add show/use completions MONGOSH-563 (#829)

Add support for autocompletion for shell commands, in particular,
`show` and `use`. Autocompletion for `use` works similar to
autocompletion for `db.<collection>`.

The implementation details for use/show autocompletion here have
been left to the shell-api package, so that changes to them do not
require any autocompletion changes.

Author: addaleax

packages/autocomplete/index.spec.ts

@@ -4,14 +4,16 @@ import { signatures as shellSignatures, Topologies } from '@mongosh/shell-api';
 import { expect } from 'chai';
 
 let collections: string[];
+let databases: string[];
 const standalone440 = {
   topology: () => Topologies.Standalone,
   connectionInfo: () => ({
     is_atlas: false,
     is_data_lake: false,
     server_version: '4.4.0'
   }),
-  getCollectionCompletionsForCurrentDb: () => collections
+  getCollectionCompletionsForCurrentDb: () => collections,
+  getDatabaseCompletions: () => databases
 };
 const sharded440 = {
   topology: () => Topologies.Sharded,
@@ -20,7 +22,8 @@ const sharded440 = {
     is_data_lake: false,
     server_version: '4.4.0'
   }),
-  getCollectionCompletionsForCurrentDb: () => collections
+  getCollectionCompletionsForCurrentDb: () => collections,
+  getDatabaseCompletions: () => databases
 };
 
 const standalone300 = {
@@ -30,7 +33,8 @@ const standalone300 = {
     is_data_lake: false,
     server_version: '3.0.0'
   }),
-  getCollectionCompletionsForCurrentDb: () => collections
+  getCollectionCompletionsForCurrentDb: () => collections,
+  getDatabaseCompletions: () => databases
 };
 const datalake440 = {
   topology: () => Topologies.Sharded,
@@ -39,13 +43,15 @@ const datalake440 = {
     is_data_lake: true,
     server_version: '4.4.0'
   }),
-  getCollectionCompletionsForCurrentDb: () => collections
+  getCollectionCompletionsForCurrentDb: () => collections,
+  getDatabaseCompletions: () => databases
 };
 
 const noParams = {
   topology: () => Topologies.Standalone,
   connectionInfo: () => undefined,
-  getCollectionCompletionsForCurrentDb: () => collections
+  getCollectionCompletionsForCurrentDb: () => collections,
+  getDatabaseCompletions: () => databases
 };
 
 describe('completer.completer', () => {
@@ -66,7 +72,7 @@ describe('completer.completer', () => {
 
     it('is an exact match to one of shell completions', async() => {
       const i = 'use';
-      expect(await completer(standalone440, i)).to.deep.equal([[i], i]);
+      expect(await completer(standalone440, i)).to.deep.equal([[], i, 'exclusive']);
     });
   });
 
@@ -482,4 +488,50 @@ describe('completer.completer', () => {
       expect(await completer(standalone440, i)).to.deep.equal([[], i]);
     });
   });
+
+  context('for shell commands', () => {
+    it('completes partial commands', async() => {
+      const i = 'sho';
+      expect(await completer(noParams, i))
+        .to.deep.equal([['show'], i]);
+    });
+
+    it('completes partial commands', async() => {
+      const i = 'show';
+      const result = await completer(noParams, i);
+      expect(result[0]).to.contain('show databases');
+    });
+
+    it('completes show databases', async() => {
+      const i = 'show d';
+      expect(await completer(noParams, i))
+        .to.deep.equal([['show databases'], i, 'exclusive']);
+    });
+
+    it('completes show profile', async() => {
+      const i = 'show pr';
+      expect(await completer(noParams, i))
+        .to.deep.equal([['show profile'], i, 'exclusive']);
+    });
+
+    it('completes use db', async() => {
+      databases = ['db1', 'db2'];
+      const i = 'use';
+      expect(await completer(noParams, i))
+        .to.deep.equal([['use db1', 'use db2'], i, 'exclusive']);
+    });
+
+    it('does not try to complete over-long commands', async() => {
+      databases = ['db1', 'db2'];
+      const i = 'use db1 d';
+      expect(await completer(noParams, i))
+        .to.deep.equal([[], i, 'exclusive']);
+    });
+
+    it('completes commands like exit', async() => {
+      const i = 'exi';
+      expect(await completer(noParams, i))
+        .to.deep.equal([['exit'], i]);
+    });
+  });
 });

packages/autocomplete/index.ts

@@ -24,6 +24,7 @@ export interface AutocompleteParameters {
     server_version: string;
   },
   getCollectionCompletionsForCurrentDb: (collName: string) => string[] | Promise<string[]>;
+  getDatabaseCompletions: (dbName: string) => string[] | Promise<string[]>;
 }
 
 export const BASE_COMPLETIONS = EXPRESSION_OPERATORS.concat(
@@ -50,7 +51,7 @@ const GROUP = '$group';
  *
  * @returns {array} Matching Completions, Current User Input.
  */
-async function completer(params: AutocompleteParameters, line: string): Promise<[string[], string]> {
+async function completer(params: AutocompleteParameters, line: string): Promise<[string[], string, 'exclusive'] | [string[], string]> {
   const SHELL_COMPLETIONS = shellSignatures.ShellApi.attributes as TypeSignatureAttributes;
   const COLL_COMPLETIONS = shellSignatures.Collection.attributes as TypeSignatureAttributes;
   const DB_COMPLETIONS = shellSignatures.Database.attributes as TypeSignatureAttributes;
@@ -60,6 +61,26 @@ async function completer(params: AutocompleteParameters, line: string): Promise<
   const CONFIG_COMPLETIONS = shellSignatures.ShellConfig.attributes as TypeSignatureAttributes;
   const SHARD_COMPLETE = shellSignatures.Shard.attributes as TypeSignatureAttributes;
 
+  const splitLineWhitespace = line.split(' ');
+  const command = splitLineWhitespace[0];
+  if (SHELL_COMPLETIONS[command]?.isDirectShellCommand) {
+    // If we encounter a direct shell commmand, we know that we want completions
+    // specific to that command, so we set the 'exclusive' flag on the result.
+    // If the shell API provides us with a completer, use it.
+    const completer = SHELL_COMPLETIONS[command].shellCommandCompleter;
+    if (completer) {
+      if (splitLineWhitespace.length === 1) {
+        splitLineWhitespace.push(''); // Treat e.g. 'show' like 'show '.
+      }
+      const hits = await completer(params, splitLineWhitespace) || [];
+      // Adjust to full input, because `completer` only completed the last item
+      // in the line, e.g. ['profile'] -> ['show profile']
+      const fullLineHits = hits.map(hit => [...splitLineWhitespace.slice(0, -1), hit].join(' '));
+      return [fullLineHits, line, 'exclusive'];
+    }
+    return [[line], line, 'exclusive'];
+  }
+
   // keep initial line param intact to always return in return statement
   // check for contents of line with:
   const splitLine = line.split('.');

packages/browser-runtime-core/src/autocompleter/shell-api-autocompleter.spec.ts

@@ -9,7 +9,8 @@ const standalone440 = {
     is_data_lake: false,
     server_version: '4.4.0'
   }),
-  getCollectionCompletionsForCurrentDb: () => ['bananas']
+  getCollectionCompletionsForCurrentDb: () => ['bananas'],
+  getDatabaseCompletions: () => ['databaseOne']
 };
 
 describe('Autocompleter', () => {
@@ -43,6 +44,14 @@ describe('Autocompleter', () => {
         completion: 'db.bananas'
       });
     });
+
+    it('returns database names after use', async() => {
+      const completions = await autocompleter.getCompletions('use da');
+
+      expect(completions).to.deep.contain({
+        completion: 'use databaseOne'
+      });
+    });
   });
 });
 

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

@@ -403,7 +403,8 @@ describe('CliRepl', () => {
       testServer: null,
       wantWatch: true,
       wantShardDistribution: true,
-      hasCollectionNames: false
+      hasCollectionNames: false,
+      hasDatabaseNames: false
     });
   });
 
@@ -566,7 +567,8 @@ describe('CliRepl', () => {
       testServer: testServer,
       wantWatch: false,
       wantShardDistribution: false,
-      hasCollectionNames: true
+      hasCollectionNames: true,
+      hasDatabaseNames: true
     });
 
     context('analytics integration', () => {
@@ -765,7 +767,8 @@ describe('CliRepl', () => {
       testServer: startTestServer('not-shared', '--replicaset', '--nodes', '1'),
       wantWatch: true,
       wantShardDistribution: false,
-      hasCollectionNames: true
+      hasCollectionNames: true,
+      hasDatabaseNames: true
     });
   });
 
@@ -774,7 +777,8 @@ describe('CliRepl', () => {
       testServer: startTestServer('not-shared', '--replicaset', '--sharded', '0'),
       wantWatch: true,
       wantShardDistribution: true,
-      hasCollectionNames: false // We're only spinning up a mongos here
+      hasCollectionNames: false, // We're only spinning up a mongos here
+      hasDatabaseNames: true
     });
   });
 
@@ -783,15 +787,17 @@ describe('CliRepl', () => {
       testServer: startTestServer('not-shared', '--auth'),
       wantWatch: false,
       wantShardDistribution: false,
-      hasCollectionNames: false
+      hasCollectionNames: false,
+      hasDatabaseNames: false
     });
   });
 
-  function verifyAutocompletion({ testServer, wantWatch, wantShardDistribution, hasCollectionNames }: {
+  function verifyAutocompletion({ testServer, wantWatch, wantShardDistribution, hasCollectionNames, hasDatabaseNames }: {
     testServer: MongodSetup | null,
     wantWatch: boolean,
     wantShardDistribution: boolean,
-    hasCollectionNames: boolean
+    hasCollectionNames: boolean,
+    hasDatabaseNames: boolean
   }): void {
     describe('autocompletion', () => {
       let cliRepl: CliRepl;
@@ -871,6 +877,24 @@ describe('CliRepl', () => {
         expect(output).not.to.include('JSON.stringify');
         expect(output).not.to.include('rawValue');
       });
+
+      it('completes shell commands', async() => {
+        input.write('const dSomeVariableStartingWithD = 10;\n');
+        await waitEval(cliRepl.bus);
+
+        output = '';
+        input.write(`show d${tab}`);
+        await waitCompletion(cliRepl.bus);
+        expect(output).to.include('show databases');
+        expect(output).not.to.include('dSomeVariableStartingWithD');
+      });
+
+      it('completes use <db>', async() => {
+        if (!hasDatabaseNames) return;
+        input.write(`use adm${tab}`);
+        await waitCompletion(cliRepl.bus);
+        expect(output).to.include('use admin');
+      });
     });
   }
 });

packages/cli-repl/src/mongosh-repl.ts

@@ -137,11 +137,19 @@ class MongoshNodeRepl implements EvaluationListener {
         this.insideAutoComplete = true;
         try {
           // Merge the results from the repl completer and the mongosh completer.
-          const [ [replResults], [mongoshResults] ] = await Promise.all([
+          const [ [replResults], [mongoshResults,, mongoshResultsExclusive] ] = await Promise.all([
             (async() => await origReplCompleter(text) || [[]])(),
             (async() => await mongoshCompleter(text))()
           ]);
           this.bus.emit('mongosh:autocompletion-complete'); // For testing.
+
+          // Sometimes the mongosh completion knows that what it is doing is right,
+          // and that autocompletion based on inspecting the actual objects that
+          // are being accessed will not be helpful, e.g. in `use a<tab>`, we know
+          // that we want *only* database names and not e.g. `assert`.
+          if (mongoshResultsExclusive) {
+            return [mongoshResults, text];
+          }
           // Remove duplicates, because shell API methods might otherwise show
           // up in both completions.
           const deduped = [...new Set([...replResults, ...mongoshResults])];

packages/shell-api/src/aggregation-cursor.spec.ts

@@ -28,7 +28,9 @@ describe('AggregationCursor', () => {
         returnType: 'AggregationCursor',
         platforms: ALL_PLATFORMS,
         topologies: ALL_TOPOLOGIES,
-        serverVersions: ALL_SERVER_VERSIONS
+        serverVersions: ALL_SERVER_VERSIONS,
+        isDirectShellCommand: false,
+        shellCommandCompleter: undefined
       });
     });
   });

packages/shell-api/src/bulk.spec.ts

@@ -39,7 +39,9 @@ describe('Bulk API', () => {
           returnType: 'BulkFindOp',
           platforms: ALL_PLATFORMS,
           topologies: ALL_TOPOLOGIES,
-          serverVersions: ALL_SERVER_VERSIONS
+          serverVersions: ALL_SERVER_VERSIONS,
+          isDirectShellCommand: false,
+          shellCommandCompleter: undefined
         });
       });
       it('hasAsyncChild', () => {
@@ -241,7 +243,9 @@ describe('Bulk API', () => {
           returnType: 'BulkFindOp',
           platforms: ALL_PLATFORMS,
           topologies: ALL_TOPOLOGIES,
-          serverVersions: ALL_SERVER_VERSIONS
+          serverVersions: ALL_SERVER_VERSIONS,
+          isDirectShellCommand: false,
+          shellCommandCompleter: undefined
         });
       });
       it('hasAsyncChild', () => {

packages/shell-api/src/change-stream-cursor.spec.ts

@@ -34,7 +34,9 @@ describe('ChangeStreamCursor', () => {
         returnType: { type: 'unknown', attributes: {} },
         platforms: ALL_PLATFORMS,
         topologies: ALL_TOPOLOGIES,
-        serverVersions: ALL_SERVER_VERSIONS
+        serverVersions: ALL_SERVER_VERSIONS,
+        isDirectShellCommand: false,
+        shellCommandCompleter: undefined
       });
     });
   });

packages/shell-api/src/collection.spec.ts

@@ -44,7 +44,9 @@ describe('Collection', () => {
         returnType: 'AggregationCursor',
         platforms: ALL_PLATFORMS,
         topologies: ALL_TOPOLOGIES,
-        serverVersions: ALL_SERVER_VERSIONS
+        serverVersions: ALL_SERVER_VERSIONS,
+        isDirectShellCommand: false,
+        shellCommandCompleter: undefined
       });
     });
     it('hasAsyncChild', () => {

packages/shell-api/src/cursor.spec.ts

@@ -32,7 +32,9 @@ describe('Cursor', () => {
         returnType: 'Cursor',
         platforms: ALL_PLATFORMS,
         topologies: ALL_TOPOLOGIES,
-        serverVersions: ALL_SERVER_VERSIONS
+        serverVersions: ALL_SERVER_VERSIONS,
+        isDirectShellCommand: false,
+        shellCommandCompleter: undefined
       });
     });
   });