stdenv: add meta.repository field

doc/stdenv/meta.chapter.md

@@ -45,6 +45,10 @@ Release branch. Used to specify that a package is not going to receive updates t
 
 The package’s homepage. Example: `https://www.gnu.org/software/hello/manual/`
 
+### `repository` {#var-meta-repository}
+
+A webpage where the package's source code can be viewed.  `https` links are preferred if available.  Automatically set to a default value if the package uses a `fetchFrom*` fetcher for its `src`. Example: `https://github.com/forthy42/gforth`
+
 ### `downloadPage` {#var-meta-downloadPage}
 
 The page where a link to the current version can be found. Example: `https://ftp.gnu.org/gnu/hello/`

pkgs/development/coq-modules/serapi/default.nix

@@ -71,7 +71,8 @@ in
           if version == "8.11.0+0.11.1" then version
           else builtins.replaceStrings [ "+" ] [ "." ] version
         }.tbz";
-    sha256 = release."${version}".sha256;
+    # abort/syntax error will fail package set eval, but throw is "fine"
+    sha256 = release."${version}".sha256 or (throw "Unknown version '${version}'");
   };
 
   patches =

pkgs/stdenv/generic/check-meta.nix

@@ -296,6 +296,10 @@ let
       str
     ];
     downloadPage = str;
+    repository = union [
+      (listOf str)
+      str
+    ];
     changelog = union [
       (listOf str)
       str
@@ -444,7 +448,29 @@ let
     let
       outputs = attrs.outputs or [ "out" ];
     in
-    {
+    optionalAttrs (attrs ? src.meta.homepage || attrs ? srcs && isList attrs.srcs && any (src: src ? meta.homepage) attrs.srcs) {
+      # should point to an http-browsable source tree, if available.
+      # fetchers like fetchFromGitHub set it automatically.
+      # this could be handled a lot easier if we nulled it instead
+      # of having it be undefined, but that wouldn't match the
+      # other attributes.
+      repository = let
+        getSrcs = attrs:
+          if attrs ? src
+          then
+            [ attrs.src ]
+          else
+            lib.filter (src: src ? meta.homepage) attrs.srcs;
+        getHomePages = srcs: map (src: src.meta.homepage) srcs;
+        unlist = list:
+          if lib.length list == 1
+          then
+            lib.elemAt list 0
+          else
+            list;
+      in
+        unlist (getHomePages (getSrcs attrs));
+    } // {
       # `name` derivation attribute includes cross-compilation cruft,
       # is under assert, and is sanitized.
       # Let's have a clean always accessible version here.