From 002129dc37d1f7ffe1001caa4e219b189384f302 Mon Sep 17 00:00:00 2001
From: Ned Twigg <ned.twigg@diffplug.com>
Date: Wed, 4 Oct 2023 00:18:10 -0700
Subject: [PATCH] Pipe the filesystem into InlineWriteTracker.persistWrites()

---
 .../diffplug/selfie/junit5/SelfieConfig.kt    |  8 ++++++
 .../junit5/SelfieTestExecutionListener.kt     |  9 ++++---
 .../diffplug/selfie/junit5/WriteTracker.kt    | 26 ++++++++++++++++---
 3 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/SelfieConfig.kt b/selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/SelfieConfig.kt
index d6f8a0be..3f5e9da7 100644
--- a/selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/SelfieConfig.kt
+++ b/selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/SelfieConfig.kt
@@ -57,6 +57,14 @@ internal class SnapshotFileLayout(
         }
     return classnameWithSlashes.replace('/', '.')
   }
+  fun testSourceFile(location: CallLocation): Path {
+    // we should have a way to have multiple source roots to check against
+    val path = rootFolder.resolve(location.subpath)
+    if (!Files.exists(path)) {
+      throw AssertionError("Unable to find ${location.subpath} at ${path.toAbsolutePath()}")
+    }
+    return path
+  }
 
   companion object {
     private const val DEFAULT_SNAPSHOT_DIR = "__snapshots__"
diff --git a/selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/SelfieTestExecutionListener.kt b/selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/SelfieTestExecutionListener.kt
index cab185df..65175502 100644
--- a/selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/SelfieTestExecutionListener.kt
+++ b/selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/SelfieTestExecutionListener.kt
@@ -82,11 +82,12 @@ internal object Router {
     }
     threadCtx.set(null)
   }
-  fun fileLocationFor(className: String): Path {
+  fun fileLocationFor(className: String): Path = layout(className).snapshotPathForClass(className)
+  fun layout(className: String): SnapshotFileLayout {
     if (layout == null) {
       layout = SnapshotFileLayout.initialize(className)
     }
-    return layout!!.snapshotPathForClass(className)
+    return layout!!
   }
 
   var layout: SnapshotFileLayout? = null
@@ -120,7 +121,9 @@ internal class ClassProgress(val className: String) {
   }
   @Synchronized fun finishedClassWithSuccess(success: Boolean) {
     assertNotTerminated()
-    inlineWriteTracker!!.persistWrites()
+    if (inlineWriteTracker!!.hasWrites()) {
+      inlineWriteTracker!!.persistWrites(Router.layout(className))
+    }
     if (file != null) {
       val staleSnapshotIndices =
           MethodSnapshotGC.findStaleSnapshotsWithin(className, file!!.snapshots, methods)
diff --git a/selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/WriteTracker.kt b/selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/WriteTracker.kt
index cf2ad5a9..624e5b2e 100644
--- a/selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/WriteTracker.kt
+++ b/selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/WriteTracker.kt
@@ -18,6 +18,8 @@ package com.diffplug.selfie.junit5
 import com.diffplug.selfie.LiteralValue
 import com.diffplug.selfie.RW
 import com.diffplug.selfie.Snapshot
+import java.nio.file.Files
+import java.nio.file.Path
 import java.util.stream.Collectors
 
 /** Represents the line at which user code called into Selfie. */
@@ -76,19 +78,37 @@ internal class InlineWriteTracker : WriteTracker<CallLocation, LiteralValue<*>>(
   fun record(call: CallStack, literalValue: LiteralValue<*>) {
     recordInternal(call.location, literalValue, call)
   }
-  fun persistWrites() {
+  fun hasWrites(): Boolean = writes.isNotEmpty()
+  fun persistWrites(layout: SnapshotFileLayout) {
     val locations = writes.toList().sortedBy { it.first }
+    var subpath = ""
     var deltaLineNumbers = 0
+    var source = ""
+    var path: Path? = null
+    // If I was implementing this, I would use Slice https://github.com/diffplug/selfie/pull/22
+    // as the type of source, but that is by no means a requirement
     for (location in locations) {
-      val currentlyInFile = "TODO"
+      if (location.first.subpath != subpath) {
+        path?.let { Files.writeString(it, source) }
+        subpath = location.first.subpath
+        deltaLineNumbers = 0
+        path = layout.testSourceFile(location.first)
+        source = Files.readString(path)
+      }
+      // parse the location within the file
+      val currentlyInFile = "TODO parse using ${location.first.line + deltaLineNumbers}"
       val literalValue = location.second.snapshot
       val parsedInFile = literalValue.format.parse(currentlyInFile)
       if (parsedInFile != literalValue.expected) {
-        // warn that the parsing wasn't quite as expected
+        // warn that the parsing wasn't as expected
+        // TODO: we can't report failures to the user very well
+        //   someday, we should verify that the parse works in the `record()` and
+        //   throw an `AssertionFail` there so that the user sees it early
       }
       val toInjectIntoFile = literalValue.encodedActual()
       deltaLineNumbers += (toInjectIntoFile.countNewlines() - currentlyInFile.countNewlines())
       // TODO: inject the encoded thing into the file
     }
+    path?.let { Files.writeString(it, source) }
   }
 }