Merge https://github.com/NixOS/nixpkgs

1 files changed, 6 insertions, 2 deletions

diff --git a/nixpkgs/lib/fileset/internal.nix b/nixpkgs/lib/fileset/internal.nix
index 23d7b847204c..35d556e78391 100644
--- a/nixpkgs/lib/fileset/internal.nix
+++ b/nixpkgs/lib/fileset/internal.nix
@@ -52,6 +52,7 @@ let
     concatStringsSep
     substring
     stringLength
+    hasSuffix
     ;
 
 in
@@ -181,7 +182,8 @@ rec {
           ${context} is of type ${typeOf value}, but it should be a file set or a path instead.''
     else if ! pathExists value then
       throw ''
-        ${context} (${toString value}) is a path that does not exist.''
+        ${context} (${toString value}) is a path that does not exist.
+            To create a file set from a path that may not exist, use `lib.fileset.maybeMissing`.''
     else
       _singleton value;
 
@@ -796,9 +798,11 @@ rec {
         if
           predicate {
             inherit name type;
+            hasExt = ext: hasSuffix ".${ext}" name;
+
             # To ensure forwards compatibility with more arguments being added in the future,
             # adding an attribute which can't be deconstructed :)
-            "lib.fileset.fileFilter: The predicate function passed as the first argument must be able to handle extra attributes for future compatibility. If you're using `{ name, file }:`, use `{ name, file, ... }:` instead." = null;
+            "lib.fileset.fileFilter: The predicate function passed as the first argument must be able to handle extra attributes for future compatibility. If you're using `{ name, file, hasExt }:`, use `{ name, file, hasExt, ... }:` instead." = null;
           }
         then
           type