fix: disallow prompts with leading or trailing spaces (usebruno#6201)

Author: bijin-bruno

packages/bruno-app/src/utils/common/codemirror.js

@@ -1,5 +1,6 @@
 import get from 'lodash/get';
 import { mockDataFunctions } from '@usebruno/common';
+import { PROMPT_VARIABLE_TEXT_PATTERN } from '@usebruno/common/utils';
 
 const CodeMirror = require('codemirror');
 
@@ -31,8 +32,8 @@ export const defineCodeMirrorBrunoVariablesMode = (_variables, mode, highlightPa
             if (ch === '}' && stream.peek() === '}') {
               stream.eat('}');
 
-              // Prompt variable: starts with '?'
-              if (word.startsWith('?')) {
+              // Prompt variable: starts with '?', no leading/trailing spaces, no braces
+              if (PROMPT_VARIABLE_TEXT_PATTERN.test(word)) {
                 return `variable-prompt`;
               }
 

packages/bruno-common/src/utils/index.ts

@@ -13,6 +13,8 @@ export {
 } from './template-hasher';
 
 export {
+  PROMPT_VARIABLE_TEXT_PATTERN,
+  PROMPT_VARIABLE_TEMPLATE_PATTERN,
   extractPromptVariables,
   extractPromptVariablesFromString
 } from './prompt-variables';

packages/bruno-common/src/utils/prompt-variables.spec.ts

@@ -45,10 +45,13 @@ describe('prompt variable utils', () => {
       expect(extractPromptVariables([{ text: 'Multiple {{?prompts}} in {{?one}} string', noPrompt: 'No prompt here' }, ['Another {{?test}} string', { prompt: '{{?nested}}', no: 'prompt' }]])).toEqual(['prompts', 'one', 'test', 'nested']);
     });
 
-    it('should deduplicate prompt variables', () => {
-      // Strings
-      expect(extractPromptVariables(['{{?world}} prompt here', 'Hello {{?world}}'])).toEqual(['world']);
-      expect(extractPromptVariables(['Multiple {{?prompts}} in {{?one}} string', 'Another {{?one}} string'])).toEqual(['prompts', 'one']);
+    it('should not extract prompt variables from invalid template patterns', () => {
+      expect(extractPromptVariables('Prompt with valid {{?inner space}}')).toEqual(['inner space']);
+      expect(extractPromptVariables('Prompt with invalid {{? leading space}}')).toEqual([]);
+      expect(extractPromptVariables('Prompt with invalid {{?trailing space }}')).toEqual([]);
+      expect(extractPromptVariables('Prompt with invalid {{?{curly brace}}')).toEqual([]);
+      expect(extractPromptVariables('Prompt with invalid {{?}curly brace}}')).toEqual([]);
+      expect(extractPromptVariables('Prompt with invalid {{?{curly brace}}}')).toEqual([]);
     });
   });
 });

packages/bruno-common/src/utils/prompt-variables.ts

@@ -1,14 +1,47 @@
+/**
+ * Inner regex pattern for prompt variable names (without braces or `?` prefix)
+ *
+ * Pattern: /[^{}\s](?:[^{}]*[^{}\s])?/
+ *
+ * Breakdown:
+ * | Part           | Meaning                                                    |
+ * | -------------- | ---------------------------------------------------------- |
+ * | `[^\s{}]`      | First character: not whitespace, `{`, or `}`               |
+ * | `(?:...)?`     | Optional non-capturing group (allows single-char names)    |
+ * | `[^{}]*`       | Middle characters: any except `{` or `}` (spaces allowed)  |
+ * | `[^\s{}]`      | Last character: not whitespace, `{`, or `}`                |
+ *
+ * This inner pattern is reused in:
+ * - PROMPT_VARIABLE_TEXT_PATTERN: Matches "?Name" format (with anchors)
+ * - PROMPT_VARIABLE_PATTERN: Matches "{{?Name}}" format (in templates)
+ *
+ * Valid examples: "Name", "Prompt Var", "x"
+ * Invalid examples: " Name", "Name ", "{Name}", "Na{me}"
+ */
+const PROMPT_VARIABLE_PATTERN = /[^{}\s](?:[^{}]*[^{}\s])?/;
+
+/**
+ * Valid examples: "?Name", "?Prompt Var", "?x"
+ * Invalid examples: "? Name", "?Name ", "?{{Name}}", "?{Name}"
+ */
+export const PROMPT_VARIABLE_TEXT_PATTERN = new RegExp(`^\\?(${PROMPT_VARIABLE_PATTERN.source})$`);
+
+/**
+ * Valid matches: "{{?Name}}", "{{?Prompt Var}}", "{{?x}}"
+ * Invalid: "{{? Name}}", "{{?Name }}", "{{?{Name}}}"
+ */
+export const PROMPT_VARIABLE_TEMPLATE_PATTERN = new RegExp(`{{\\?(${PROMPT_VARIABLE_PATTERN.source})}}`, 'g');
+
 /**
  * Extract prompt variables matching {{?<Prompt Text>}} from a string.
  * @param {string} str - The input string.
  * @returns {string[]} - An array of extracted prompt variables.
  */
 export const extractPromptVariablesFromString = (str: string): string[] => {
-  const regex = /{{\?([^}]+)}}/g;
   const prompts = new Set<string>();
   let match;
-  while ((match = regex.exec(str)) !== null) {
-    prompts.add(match[1].trim());
+  while ((match = PROMPT_VARIABLE_TEMPLATE_PATTERN.exec(str)) !== null) {
+    prompts.add(match[1]);
   }
   return Array.from(prompts);
 };