ADFA-4816: Prune excluded dirs during Spotless traversal

build.gradle.kts

@@ -140,6 +140,48 @@ spotless {
 			"termux/**/*",
 		)
 
+	// Dirs to PRUNE during the walk. Passing a fileTree to target() bypasses
+	// Spotless's auto-prune of .git/.gradle/build, so restore them. flox is the
+	// ADFA-4816 fix: its /nix/store symlinks (millions of files) made
+	// spotlessCheck take 12+ minutes.
+	// Bare dir names required: Gradle prunes a subtree only when an exclude
+	// matches the dir node itself; `dir/**` matches contents and forces a
+	// descend-and-filter (no pruning).
+	val traversalExcludes =
+		arrayOf(
+			"flox",
+			"**/.flox",
+			"**/.git",
+			"**/.gradle",
+		)
+
+	// Gradle build-output dirs (root + subprojects), relative to rootDir. Not
+	// "**/build": source packages named `build` exist (e.g.
+	// app/src/main/java/.../actions/build) and would be dropped.
+	val buildOutputExcludes =
+		allprojects
+			.map {
+				it.layout.buildDirectory
+					.get()
+					.asFile
+					.relativeTo(rootDir)
+					.invariantSeparatorsPath
+			}.filter { it.isNotEmpty() && !it.startsWith("..") }
+			.toTypedArray()
+
+	// Target tree with the shared excludes applied; format-specific ones go in
+	// extraExcludes.
+	fun spotlessTarget(
+		vararg includes: String,
+		extraExcludes: Array<String> = emptyArray(),
+	) = fileTree(rootDir) {
+		include(*includes)
+		exclude(*commonTargetExcludes)
+		exclude(*traversalExcludes)
+		exclude(*buildOutputExcludes)
+		exclude(*extraExcludes)
+	}
+
 	// ALWAYS use line feeds (LF -- '\n')
 	lineEndings = LineEnding.UNIX
 
@@ -181,8 +223,7 @@ spotless {
 			},
 		)
 
-		target("**/src/*/java/**/*.java")
-		targetExclude(*commonTargetExcludes)
+		target(spotlessTarget("**/src/*/java/**/*.java"))
 	}
 
 	kotlin {
@@ -197,10 +238,11 @@ spotless {
 		endWithNewline()
 
 		target(
-			"**/src/*/java/**/*.kt",
-			"**/src/*/kotlin/**/*.kt",
+			spotlessTarget(
+				"**/src/*/java/**/*.kt",
+				"**/src/*/kotlin/**/*.kt",
+			),
 		)
-		targetExclude(*commonTargetExcludes)
 
 		suppressLintsFor {
 			// suppress the 'file name <some-file> should conform PascalCase' errors
@@ -215,8 +257,7 @@ spotless {
 		trimTrailingWhitespace()
 		endWithNewline()
 
-		target("**/*.gradle.kts")
-		targetExclude(*commonTargetExcludes)
+		target(spotlessTarget("**/*.gradle.kts"))
 	}
 
 	format("xml") {
@@ -227,22 +268,22 @@ spotless {
 		trimTrailingWhitespace()
 		endWithNewline()
 
-		target("**/src/*/res/**/*.xml")
-		targetExclude(*commonTargetExcludes)
-
-		// Formatting strings.xml with Eclipse WTP causes the strings to be
-		// split into multiple lines, which is not what we want.
-		// Exclude strings.xml from this rule.
-		targetExclude("**/src/*/res/values*/strings.xml")
+		// Eclipse WTP splits strings.xml entries across lines, so exclude it.
+		target(
+			spotlessTarget(
+				"**/src/*/res/**/*.xml",
+				extraExcludes = arrayOf("**/src/*/res/values*/strings.xml"),
+			),
+		)
 	}
 
 	format("misc") {
 		leadingSpacesToTabs()
 		trimTrailingWhitespace()
 		endWithNewline()
 
-		target("**/.gitignore", "**/.gradle")
-		targetExclude(*commonTargetExcludes)
+		// Only .gitignore; `.gradle` is a cache dir, pruned via traversalExcludes.
+		target(spotlessTarget("**/.gitignore"))
 	}
 
 	shell {