Subject: [PATCH] userdiff: improve java regex for generic return types

From: Tassilo Horn <[email-masked]>
Date: Mon, 9 Aug 2021 22:33:08 +0200

Currently, the git diff hunk headers show the wrong method signature if the
method has a generic return type because the regex doesn't allow < and > in the
return type.  This patch adds those.

Bug repro: In a repository with .gitattributes containing "*.java diff=java"
and a java file

--8<---------------cut here---------------start------------->8---
class MyExample {
    public void firstMethod() {
        // Whatever...
    }

    public List<Integer> secondMethod() {
        // Here is some comment,
        // and here is more,
        // and here is even more,
        // followed by this,
        // and that,
        // and even more.
        return Arrays.asList(1, 2, 3, 4, 5);
    }
}
--8<---------------cut here---------------end--------------->8---

when adding the number 6 to the Arrays.asList() call in secondMethod(), the git
diff one gets is

--8<---------------cut here---------------start------------->8---
diff --git a/src/main/java/MyExample.java b/src/main/java/MyExample.java
index a0f1a6b..ea37a98 100644
--- a/src/main/java/MyExample.java
+++ b/src/main/java/MyExample.java
@@ -14,6 +14,6 @@ public void firstMethod() {
         // followed by this,
         // and that,
         // and even more.
-        return Arrays.asList(1, 2, 3, 4, 5);
+        return Arrays.asList(1, 2, 3, 4, 5, 6);
     }
 }
--8<---------------cut here---------------end--------------->8---

where the hunk header shows the signature of firstMethod whereas it should show
the signature of secondMethod.

Signed-off-by: Tassilo Horn <[email-masked]>
---
 userdiff.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/userdiff.c b/userdiff.c
index 3c3bbe38b0..a244ad7ab1 100644
--- a/userdiff.c
+++ b/userdiff.c
@@ -142,7 +142,7 @@ PATTERNS("html",
 	 "[^<>= \t]+"),
 PATTERNS("java",
 	 "!^[ \t]*(catch|do|for|if|instanceof|new|return|switch|throw|while)\n"
-	 "^[ \t]*(([A-Za-z_][A-Za-z_0-9]*[ \t]+)+[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*)$",
+	 "^[ \t]*(([A-Za-z_][A-Za-z_0-9<>]*[ \t]+)+[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*)$",
 	 /* -- */
 	 "[a-zA-Z_][a-zA-Z0-9_]*"
 	 "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
-- 
2.32.0