fix: any last argument matching Throwable.toString() is left as is (#229)c

pdelagrave · web-flow · commit 1aa395260b18 · 2025-06-26T22:03:19.000+02:00
In SLF4J, the last argument of the logging methods will be treated specially and removed from the formatted string argument array if it's a Throwable. When the last argument was a `.toString()` call we stripped it even if it was a `Throwable` which changed the behaviour. https://www.slf4j.org/faq.html#paramException
diff --git a/src/main/java/org/openrewrite/java/logging/slf4j/StripToStringFromArguments.java b/src/main/java/org/openrewrite/java/logging/slf4j/StripToStringFromArguments.java
@@ -78,7 +78,7 @@ public J.MethodInvocation visitMethodInvocation(J.MethodInvocation m, ExecutionC
                                 J.MethodInvocation toStringInvocation = (J.MethodInvocation) arg;
                                 if (TO_STRING_MATCHER.matches(toStringInvocation.getMethodType()) &&
                                     toStringInvocation.getSelect() != null &&
-                                    !(firstFormatArgIndex == lastArgIndex && TypeUtils.isAssignableTo("java.lang.Throwable", toStringInvocation.getSelect().getType()))) {
+                                    !(index == lastArgIndex && TypeUtils.isAssignableTo("java.lang.Throwable", toStringInvocation.getSelect().getType()))) {
                                     // Strip the `.toString()` call
                                     return toStringInvocation.getSelect().withPrefix(toStringInvocation.getPrefix());
                                 }
diff --git a/src/test/java/org/openrewrite/java/logging/slf4j/StripToStringFromArgumentsTest.java b/src/test/java/org/openrewrite/java/logging/slf4j/StripToStringFromArgumentsTest.java
@@ -57,7 +57,7 @@ record TestCase(String originalArgs, String expectedArgs) {
                         ", exception, o1"),
                 new TestCase(
                         ", o1, exception.toString()",
-                        ", o1, exception")
+                        ", o1, exception.toString()")
         );
 
         return Stream.of("trace", "debug", "info", "warn", "error")

Original file line number	Diff line number	Diff line change
`@@ -78,7 +78,7 @@ public J.MethodInvocation visitMethodInvocation(J.MethodInvocation m, ExecutionC`
`78`	`78`	`J.MethodInvocation toStringInvocation = (J.MethodInvocation) arg;`
`79`	`79`	`if (TO_STRING_MATCHER.matches(toStringInvocation.getMethodType()) &&`
`80`	`80`	`toStringInvocation.getSelect() != null &&`
`81`		`- !(firstFormatArgIndex == lastArgIndex && TypeUtils.isAssignableTo("java.lang.Throwable", toStringInvocation.getSelect().getType()))) {`
	`81`	`+ !(index == lastArgIndex && TypeUtils.isAssignableTo("java.lang.Throwable", toStringInvocation.getSelect().getType()))) {`
`82`	`82`	// Strip the `.toString()` call
`83`	`83`	`return toStringInvocation.getSelect().withPrefix(toStringInvocation.getPrefix());`
`84`	`84`	`}`