Implement stabilityPatternToRegex (#110)

Author: skydoves

compose-stability-analyzer-idea/src/main/kotlin/com/skydoves/compose/stability/idea/settings/StabilityProjectSettingsState.kt

@@ -71,10 +71,7 @@ public class StabilityProjectSettingsState :
 
       patterns.mapNotNull { pattern ->
         try {
-          pattern
-            .replace(".", "\\.")
-            .replace("*", ".*")
-            .toRegex()
+          stabilityPatternToRegex(pattern)
         } catch (e: Exception) {
           null
         }

compose-stability-analyzer-idea/src/main/kotlin/com/skydoves/compose/stability/idea/settings/StabilitySettingsState.kt

@@ -144,11 +144,7 @@ public class StabilitySettingsState : PersistentStateComponent<StabilitySettings
       .filter { it.isNotEmpty() && !it.startsWith("#") } // Support comments
       .map { pattern ->
         try {
-          // Convert glob-style wildcards to regex
-          pattern
-            .replace(".", "\\.")
-            .replace("*", ".*")
-            .toRegex()
+          stabilityPatternToRegex(pattern)
         } catch (e: Exception) {
           // If regex is invalid, treat as literal string
           Regex.escape(pattern).toRegex()
@@ -183,11 +179,7 @@ public class StabilitySettingsState : PersistentStateComponent<StabilitySettings
       // Convert patterns to regex
       patterns.mapNotNull { pattern ->
         try {
-          // Convert glob-style wildcards to regex
-          pattern
-            .replace(".", "\\.")
-            .replace("*", ".*")
-            .toRegex()
+          stabilityPatternToRegex(pattern)
         } catch (e: Exception) {
           null // Skip invalid patterns
         }
@@ -203,3 +195,43 @@ public class StabilitySettingsState : PersistentStateComponent<StabilitySettings
     }
   }
 }
+
+/**
+ * Converts a Compose stability configuration pattern to a [Regex].
+ *
+ * Follows the same semantics as the Compose compiler's stability configuration file:
+ * - `**` matches any sequence of characters including dots (multi-segment wildcard)
+ * - `*` matches any sequence of characters except dots (single-segment wildcard)
+ * - `.` is treated as a literal dot
+ * - All other characters are regex-escaped
+ *
+ * Examples:
+ * - `com.datalayer.*` matches `com.datalayer.Foo` but NOT `com.datalayer.sub.Foo`
+ * - `com.datalayer.**` matches `com.datalayer.Foo` AND `com.datalayer.sub.Foo`
+ */
+internal fun stabilityPatternToRegex(pattern: String): Regex {
+  val regex = buildString {
+    var i = 0
+    while (i < pattern.length) {
+      when {
+        pattern[i] == '*' && i + 1 < pattern.length && pattern[i + 1] == '*' -> {
+          append(".*")
+          i += 2
+        }
+        pattern[i] == '*' -> {
+          append("[^.]*")
+          i++
+        }
+        pattern[i] == '.' -> {
+          append("\\.")
+          i++
+        }
+        else -> {
+          append(Regex.escape(pattern[i].toString()))
+          i++
+        }
+      }
+    }
+  }
+  return regex.toRegex()
+}

compose-stability-analyzer-idea/src/test/kotlin/com/skydoves/compose/stability/idea/settings/StabilitySettingsStateTest.kt

@@ -114,8 +114,9 @@ class StabilitySettingsStateTest {
     val patterns = settings.getIgnoredPatternsAsRegex()
     assertEquals(1, patterns.size)
 
+    // Single * matches only one package segment (no dots)
     assertTrue(patterns[0].matches("com.example.User"))
-    assertTrue(patterns[0].matches("com.example.ui.Card"))
+    assertFalse(patterns[0].matches("com.example.ui.Card"))
     assertFalse(patterns[0].matches("com.other.User"))
   }
 
@@ -170,14 +171,31 @@ class StabilitySettingsStateTest {
   }
 
   @Test
-  fun testGetIgnoredPatternsAsRegex_handlesWildcards() {
+  fun testGetIgnoredPatternsAsRegex_singleStarMatchesSingleSegment() {
     val settings = StabilitySettingsState()
     settings.ignoredTypePatterns = "com.example.*"
 
     val patterns = settings.getIgnoredPatternsAsRegex()
     assertEquals(1, patterns.size)
 
-    // Wildcard should match multiple segments
+    // Single * matches only one segment (no dots)
+    assertTrue(patterns[0].matches("com.example.User"))
+    assertFalse(patterns[0].matches("com.example.ui.UserCard"))
+    assertFalse(patterns[0].matches("com.example.data.model.User"))
+
+    // Should not match different package
+    assertFalse(patterns[0].matches("com.other.User"))
+  }
+
+  @Test
+  fun testGetIgnoredPatternsAsRegex_doubleStarMatchesMultipleSegments() {
+    val settings = StabilitySettingsState()
+    settings.ignoredTypePatterns = "com.example.**"
+
+    val patterns = settings.getIgnoredPatternsAsRegex()
+    assertEquals(1, patterns.size)
+
+    // Double ** matches across package boundaries (including dots)
     assertTrue(patterns[0].matches("com.example.User"))
     assertTrue(patterns[0].matches("com.example.ui.UserCard"))
     assertTrue(patterns[0].matches("com.example.data.model.User"))
@@ -262,7 +280,7 @@ class StabilitySettingsStateTest {
   }
 
   @Test
-  fun testGetCustomStableTypesAsRegex_handlesInvalidRegex() {
+  fun testGetCustomStableTypesAsRegex_handlesSpecialCharacters() {
     val configFile = tempFolder.newFile("stability-config.txt")
     configFile.writeText(
       """
@@ -277,10 +295,11 @@ class StabilitySettingsStateTest {
 
     val patterns = settings.getCustomStableTypesAsRegex()
 
-    // Should skip invalid patterns and only include valid ones
-    assertEquals(2, patterns.size)
+    // All patterns are valid (special characters are properly escaped)
+    assertEquals(3, patterns.size)
     assertTrue(patterns[0].matches("com.example.ValidClass"))
-    assertTrue(patterns[1].matches("com.example.AnotherValid"))
+    assertTrue(patterns[1].matches("[invalid(regex"))
+    assertTrue(patterns[2].matches("com.example.AnotherValid"))
   }
 
   @Test
@@ -378,8 +397,8 @@ class StabilitySettingsStateTest {
   }
 
   @Test
-  fun testGetCustomStableTypesAsRegex_wildcardMatching() {
-    val configFile = tempFolder.newFile("stability-config.txt")
+  fun testGetCustomStableTypesAsRegex_singleStarWildcard() {
+    val configFile = tempFolder.newFile("stability-config-single.txt")
     configFile.writeText("com.example.stable.*")
 
     val settings = StabilitySettingsState()
@@ -388,8 +407,27 @@ class StabilitySettingsStateTest {
     val patterns = settings.getCustomStableTypesAsRegex()
     assertEquals(1, patterns.size)
 
+    // Single * matches only direct children
+    assertTrue(patterns[0].matches("com.example.stable.User"))
+    assertFalse(patterns[0].matches("com.example.stable.data.Repository"))
+    assertFalse(patterns[0].matches("com.example.unstable.User"))
+  }
+
+  @Test
+  fun testGetCustomStableTypesAsRegex_doubleStarWildcard() {
+    val configFile = tempFolder.newFile("stability-config-double.txt")
+    configFile.writeText("com.example.stable.**")
+
+    val settings = StabilitySettingsState()
+    settings.stabilityConfigurationPath = configFile.absolutePath
+
+    val patterns = settings.getCustomStableTypesAsRegex()
+    assertEquals(1, patterns.size)
+
+    // Double ** matches across subpackages
     assertTrue(patterns[0].matches("com.example.stable.User"))
     assertTrue(patterns[0].matches("com.example.stable.data.Repository"))
+    assertTrue(patterns[0].matches("com.example.stable.data.model.Entity"))
     assertFalse(patterns[0].matches("com.example.unstable.User"))
   }
 }