Re: [PATCH v3 32/35] userdiff golang: add a rule to match "package"

> Improve the "golang" built-in pattern to match "package" lines, as
> they weren't matched before changing e.g. the imports would commonly
> result in an empty hunk header, now we'll instead show the package
> name.
> 
> I used https://blog.golang.org/package-names as a guide here, but
> e.g. "foo_bar" is still valid syntax, so let's let it pass but veer on
> the side of not having false positives.
> 
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
>  t/t4018/golang | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
>  userdiff.c     |  2 ++
>  2 files changed, 51 insertions(+)
> 
> diff --git a/t/t4018/golang b/t/t4018/golang
> index 252b6049da4..38f254cd269 100644
> --- a/t/t4018/golang
> +++ b/t/t4018/golang
> @@ -1,3 +1,52 @@
> +t4018 description: package
> +t4018 header: package main
> +package main
> +
> +import "fmt"
> +// ChangeMe
> +
> +t4018 description: package regex is selective -- ALLCAPS
> +t4018 header: package main
> +package ALLCAPS
> +
> +import "fmt"
> +// ChangeMe
> +
> +t4018 description: package regex is selective -- CamelCase
> +t4018 header: package main
> +package CamelCase
> +
> +import "fmt"
> +// ChangeMe
> +
> +t4018 description: package regex is selective -- 123
> +t4018 header: package main
> +package 123
> +
> +import "fmt"
> +// ChangeMe
> +
> +t4018 description: package regex is not overly selective -- x509
> +t4018 header: package x509
> +package x509
> +
> +import "fmt"
> +// ChangeMe
> +
> +t4018 description: package regex is not overly selective -- underbars
> +t4018 header: package not_conventional
> +package not_conventional
> +
> +import "fmt"
> +// ChangeMe
> +
> +t4018 description: package regex is not overly selective -- camelCase
> +t4018 header: package camelCase
> +package camelCase
> +
> +import "fmt"
> +// ChangeMe
> +
>  t4018 description: complex function
>  t4018 header: func (t *Test) RIGHT(a Type) (Type, error) {
>  type Test struct {
> diff --git a/userdiff.c b/userdiff.c
> index 704af241e44..bbbbfa33e0a 100644
> --- a/userdiff.c
> +++ b/userdiff.c
> @@ -128,6 +128,8 @@ IPATTERN("fountain",
>  	 /* -- */
>  	 "[^ \t-]+"),
>  PATTERNS("golang",
> +	 /* Packages */
> +	 "^(package[ \t][a-z][A-Za-z0-9_]+)[ \t]*\n"