fix(amazonq): update logic for converting gitignore pattern to regex

Author: Gaurav Gandhi

plugins/amazonq/chat/jetbrains-community/tst/software/aws/toolkits/jetbrains/services/amazonqFeatureDev/FeatureDevSessionContextTest.kt

@@ -161,4 +161,37 @@ class FeatureDevSessionContextTest : FeatureDevTestBase(HeavyJavaCodeInsightTest
 
         assertEquals(zippedFiles, expectedFiles)
     }
+
+    @Test
+    fun testConvertGitIgnorePatternToRegex() {
+        val sampleGitIgnorePatterns = listOf(".*", "build/", "*.txt", "*.png")
+        val sampleFileNames = listOf(
+            ".gitignore/",
+            ".env/",
+            "file.txt/",
+            ".git/config/",
+            "src/file.txt/",
+            "build/",
+            "build/output.jar/",
+            "builds/",
+            "mybuild/",
+            "build.json/",
+            "log.txt/",
+            "file.txt.json/",
+            "file.png/",
+            "src/file.png/"
+        )
+
+        val patterns = sampleGitIgnorePatterns.map { pattern -> featureDevSessionContext.convertGitIgnorePatternToRegex(pattern).toRegex() }
+
+        val matchedFiles = sampleFileNames.filter { fileName ->
+            patterns.any { pattern ->
+                pattern.matches(fileName)
+            }
+        }
+
+        val expectedFilesToMatch = listOf(".gitignore/", ".env/", "file.txt/", ".git/config/", "src/file.txt/", "build/", "build/output.jar/", "log.txt/", "file.png/", "src/file.png/")
+
+        assertEquals(expectedFilesToMatch, matchedFiles)
+    }
 }

plugins/core/jetbrains-community/src/software/aws/toolkits/jetbrains/services/amazonq/FeatureDevSessionContext.kt

@@ -279,10 +279,17 @@ class FeatureDevSessionContext(val project: Project, val maxProjectSizeBytes: Lo
     }
 
     // gitignore patterns are not regex, method update needed.
-    private fun convertGitIgnorePatternToRegex(pattern: String): String = pattern
-        .replace(".", "\\.")
-        .replace("*", ".*")
-        .let { if (it.endsWith("/")) "$it.*" else "$it/.*" } // Add a trailing /* to all patterns. (we add a trailing / to all files when matching)
+    fun convertGitIgnorePatternToRegex(pattern: String): String {
+        // Special case for ".*" to match only dotfiles
+        if (pattern == ".*") {
+            return "^\\..*/.*"
+        }
+
+        return pattern
+            .replace(".", "\\.")
+            .replace("*", ".*")
+            .let { if (it.endsWith("/")) "$it.*" else "$it/.*" } // Add a trailing /* to all patterns. (we add a trailing / to all files when matching)
+    }
     var selectedSourceFolder: VirtualFile
         set(newRoot) {
             _selectedSourceFolder = newRoot