Make JRE parsing more robust (#694)

diffplug · Sep 12, 2020 · 511b18b · 511b18b
2 parents d0d2170 + 7cc232e
commit 511b18b
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Showing 5 changed files with 29 additions and 6 deletions.
diff --git a/CHANGES.md b/CHANGES.md
@@ -10,6 +10,8 @@ This document is intended for Spotless developers.
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `1.27.0`).
 
 ## [Unreleased]
+### Fixed
+* Improved JRE parsing to handle strings like `16-loom` (fixes [#693](https://github.com/diffplug/spotless/issues/693)).
 
 ## [2.6.0] - 2020-09-11
 ### Added

diff --git a/lib/src/main/java/com/diffplug/spotless/java/GoogleJavaFormatStep.java b/lib/src/main/java/com/diffplug/spotless/java/GoogleJavaFormatStep.java
@@ -19,6 +19,8 @@
 import java.io.Serializable;
 import java.lang.reflect.Method;
 import java.util.Objects;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 import com.diffplug.spotless.FormatterFunc;
 import com.diffplug.spotless.FormatterStep;
@@ -81,7 +83,14 @@ public static FormatterStep create(String version, String style, Provisioner pro
 		if (jre.startsWith("1.8")) {
 			JRE_VERSION = 8;
 		} else {
-			JRE_VERSION = Integer.parseInt(jre.substring(0, jre.indexOf('.')));
+			Matcher matcher = Pattern.compile("(\\d+)").matcher(jre);
+			if (!matcher.find()) {
+				throw new IllegalArgumentException("Expected " + jre + " to start with an integer");
+			}
+			JRE_VERSION = Integer.parseInt(matcher.group(1));
+			if (JRE_VERSION <= 8) {
+				throw new IllegalArgumentException("Expected " + jre + " to start with an integer greater than 8");
+			}
 		}
 	}
 

diff --git a/plugin-gradle/CHANGES.md b/plugin-gradle/CHANGES.md
@@ -3,6 +3,8 @@
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `3.27.0`).
 
 ## [Unreleased]
+### Fixed
+* Improved JRE parsing to handle strings like `16-loom` (fixes [#693](https://github.com/diffplug/spotless/issues/693)).
 
 ## [5.5.0] - 2020-09-11
 ### Added

diff --git a/plugin-maven/CHANGES.md b/plugin-maven/CHANGES.md
@@ -3,6 +3,8 @@
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `1.27.0`).
 
 ## [Unreleased]
+### Fixed
+* Improved JRE parsing to handle strings like `16-loom` (fixes [#693](https://github.com/diffplug/spotless/issues/693)).
 
 ## [2.3.0] - 2020-09-11
 ### Added

diff --git a/testlib/src/main/java/com/diffplug/spotless/JreVersion.java b/testlib/src/main/java/com/diffplug/spotless/JreVersion.java
@@ -16,19 +16,27 @@
 package com.diffplug.spotless;
 
 import java.util.function.IntPredicate;
-
-import com.diffplug.common.base.StandardSystemProperty;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 public class JreVersion {
 	private JreVersion() {}
 
 	/** Returns the major version of this VM, e.g. 8, 9, 10, 11, 13, etc. */
 	public static int thisVm() {
-		String jvmVersion = StandardSystemProperty.JAVA_VERSION.value();
-		if (jvmVersion.startsWith("1.8.")) {
+		String jre = System.getProperty("java.version");
+		if (jre.startsWith("1.8")) {
 			return 8;
 		} else {
-			return Integer.parseInt(jvmVersion.substring(0, jvmVersion.indexOf('.')));
+			Matcher matcher = Pattern.compile("(\\d+)").matcher(jre);
+			if (!matcher.find()) {
+				throw new IllegalArgumentException("Expected " + jre + " to start with an integer");
+			}
+			int version = Integer.parseInt(matcher.group(1));
+			if (version <= 8) {
+				throw new IllegalArgumentException("Expected " + jre + " to start with an integer greater than 8");
+			}
+			return version;
 		}
 	}