Re: [PATCH v4] userdiff: improve java hunk header regex

> Currently, the git diff hunk headers show the wrong method signature if the
> method has a qualified return type, an array return type, or a generic return
> type because the regex doesn't allow dots (.), [], or < and > in the return
> type.  Also, type parameter declarations couldn't be matched.
> 
> Add several t4018 tests asserting the right hunk headers for increasingly
> complex method signatures:
> 
>   public String[] myMethod(String[] RIGHT)
>   public List<String> myMethod(String[] RIGHT)
>   public <T> List<T> myMethod(T[] RIGHT)
>   public <AType, B> Map<AType, B> myMethod(String[] RIGHT)
>   public <AType, B> java.util.Map<AType, Map<B, B[]>> myMethod(String[] RIGHT)
>   public List<? extends Comparable> myMethod(String[] RIGHT)
>   public <T extends Serializable & Comparable<T>> List<T> myMethod(String[] RIGHT)
> 
> Signed-off-by: Tassilo Horn <tsdh@gnu.org>
> ---
>  t/t4018/java-constructor             |  6 ++++++
>  t/t4018/java-enum-constant           |  6 ++++++
>  t/t4018/java-nested-field            |  6 ++++++
>  t/t4018/java-return-array            |  6 ++++++
>  t/t4018/java-return-generic          |  6 ++++++
>  t/t4018/java-return-generic-bounded  |  6 ++++++
>  t/t4018/java-return-generic-wildcart |  6 ++++++
>  t/t4018/java-return-generic2         |  6 ++++++
>  t/t4018/java-return-generic3         |  6 ++++++
>  t/t4018/java-return-generic4         |  6 ++++++
>  userdiff.c                           | 23 ++++++++++++++++++++++-
>  11 files changed, 82 insertions(+), 1 deletion(-)
>  create mode 100644 t/t4018/java-constructor
>  create mode 100644 t/t4018/java-enum-constant
>  create mode 100644 t/t4018/java-nested-field
>  create mode 100644 t/t4018/java-return-array
>  create mode 100644 t/t4018/java-return-generic
>  create mode 100644 t/t4018/java-return-generic-bounded
>  create mode 100644 t/t4018/java-return-generic-wildcart
>  create mode 100644 t/t4018/java-return-generic2
>  create mode 100644 t/t4018/java-return-generic3
>  create mode 100644 t/t4018/java-return-generic4
> 

> diff --git a/t/t4018/java-return-array b/t/t4018/java-return-array
> new file mode 100644
> index 0000000000..747638b9a8
> --- /dev/null
> +++ b/t/t4018/java-return-array
> @@ -0,0 +1,6 @@
> +class MyExample {
> +    public String[] myMethod(String[] RIGHT) {
> +        // Whatever...
> +        return new; // ChangeMe
> +    }
> +}
> diff --git a/userdiff.c b/userdiff.c
> index 3c3bbe38b0..9bd751b7d2 100644
> --- a/userdiff.c
> +++ b/userdiff.c
> @@ -142,7 +142,28 @@ 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]*\\([^;]*)$",
> +         "^[ \t]*("
> +         /* Class, enum, and interface declarations: */
> +         /*   optional modifiers: public */
> +         "(([a-z]+[ \t]+)*"
> +         /*   the kind of declaration */
> +         "(class|enum|interface)[ \t]+"
> +         /*   the name */
> +         "[A-Za-z][A-Za-z0-9_$]*[ \t]+.*)"
> +         /* Method & constructor signatures: */
> +         /*   optional modifiers: public static */
> +         "|(([a-z]+[ \t]+)*"
> +         /*   type params and return types for methods but not constructors */
> +         "("
> +         /*     optional type parameters: <A, B extends Comparable<B>> */
> +         "(<[A-Za-z0-9_,.&<> \t]+>[ \t]+)?"
> +         /*     return type: java.util.Map<A, B[]> or List<?> */
> +         "([A-Za-z_]([A-Za-z_0-9<>,.?]|\\[[ \t]*\\])*[ \t]+)+"
> +         /*   end of type params and return type */
> +         ")?"
> +         /*   the method name followed by the parameter list: myMethod(...) */
> +         "[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*)"
> +         ")$",