From a047c3682a5dab463c02acf7fe6d13659befb9f7 Mon Sep 17 00:00:00 2001
From: Alexey Tsvetkov <alexey.tsvetkov@jetbrains.com>
Date: Wed, 5 Apr 2017 22:40:22 +0300
Subject: [PATCH] Invalidate cache version if corresponding file is empty

Sometimes an expression `versionFile.readText()`
returns an empty string, so that `toInt()` fails
with `NumberFormatException`.

It can happen in with both JPS and Gradle.
I could not reproduce the problem,
and it seems to be impossible (under normal circumstances),
because we always write a non-empty string,
and the file is checked to exist before reading.
Maybe it could be caused by an FS error.

The only "solution" to the problem I could think
is to swallow the exception, and assume
that cache version is not valid (so it would cause a rebuild of a module).

    #KT-17125 fixed
---
 .../jetbrains/kotlin/incremental/CacheVersion.kt    | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/build-common/src/org/jetbrains/kotlin/incremental/CacheVersion.kt b/build-common/src/org/jetbrains/kotlin/incremental/CacheVersion.kt
index 481672b8c97..7a6d9b4c64d 100644
--- a/build-common/src/org/jetbrains/kotlin/incremental/CacheVersion.kt
+++ b/build-common/src/org/jetbrains/kotlin/incremental/CacheVersion.kt
@@ -21,6 +21,7 @@ import org.jetbrains.kotlin.config.IncrementalCompilation
 import org.jetbrains.kotlin.load.java.JvmBytecodeBinaryVersion
 import org.jetbrains.kotlin.load.kotlin.JvmMetadataVersion
 import java.io.File
+import java.io.IOException
 
 private val NORMAL_VERSION = 8
 private val EXPERIMENTAL_VERSION = 4
@@ -40,8 +41,16 @@ class CacheVersion(
 ) {
     private val isEnabled by lazy(isEnabled)
 
-    private val actualVersion: Int
-        get() = versionFile.readText().toInt()
+    private val actualVersion: Int?
+        get() = try {
+            versionFile.readText().toInt()
+        }
+        catch (e: NumberFormatException) {
+            null
+        }
+        catch (e: IOException) {
+            null
+        }
 
     private val expectedVersion: Int
         get() {