Merge master into haskell-updates

doc/languages-frameworks/rust.section.md

@@ -963,7 +963,7 @@ repository:
      lib.updateManyAttrsByPath [{
        path = [ "packages" "stable" ];
        update = old: old.overrideScope(final: prev: {
-         rustc = prev.rustc.overrideAttrs (_: {
+         rustc-unwrapped = prev.rustc-unwrapped.overrideAttrs (_: {
            src = lib.cleanSource /git/scratch/rust;
            # do *not* put passthru.isReleaseTarball=true here
          });
@@ -1003,4 +1003,3 @@ nix-build $NIXPKGS -A package-broken-by-rust-changes
 The `git submodule update --init` and `cargo vendor` commands above
 require network access, so they can't be performed from within the
 `rustc` derivation, unfortunately.
-

flake.nix

@@ -9,7 +9,8 @@
         nixpkgs = self;
       };
 
-      lib = import ./lib;
+      libVersionInfoOverlay = import ./lib/flake-version-info.nix self;
+      lib = (import ./lib).extend libVersionInfoOverlay;
 
       forAllSystems = lib.genAttrs lib.systems.flakeExposed;
     in
@@ -20,13 +21,7 @@
 
         nixosSystem = args:
           import ./nixos/lib/eval-config.nix (
-            args // {
-              modules = args.modules ++ [{
-                system.nixos.versionSuffix =
-                  ".${final.substring 0 8 (self.lastModifiedDate or self.lastModified or "19700101")}.${self.shortRev or "dirty"}";
-                system.nixos.revision = final.mkIf (self ? rev) self.rev;
-              }];
-            } // lib.optionalAttrs (! args?system) {
+            args // { inherit (self) lib; } // lib.optionalAttrs (! args?system) {
               # Allow system to be set modularly in nixpkgs.system.
               # We set it to null, to remove the "legacy" entrypoint's
               # non-hermetic default.
@@ -53,7 +48,11 @@
       # attribute it displays `omitted` instead of evaluating all packages,
       # which keeps `nix flake show` on Nixpkgs reasonably fast, though less
       # information rich.
-      legacyPackages = forAllSystems (system: import ./. { inherit system; });
+      legacyPackages = forAllSystems (system:
+        (import ./. { inherit system; }).extend (final: prev: {
+          lib = prev.lib.extend libVersionInfoOverlay;
+        })
+      );
 
       nixosModules = {
         notDetected = ./nixos/modules/installer/scan/not-detected.nix;

lib/attrsets.nix

@@ -51,12 +51,19 @@ rec {
 
   /* Return if an attribute from nested attribute set exists.
 
+     **Laws**:
+      1.  ```nix
+          hasAttrByPath [] x == true
+          ```
+
      Example:
        x = { a = { b = 3; }; }
        hasAttrByPath ["a" "b"] x
        => true
        hasAttrByPath ["z" "z"] x
        => false
+       hasAttrByPath [] (throw "no need")
+       => true
 
     Type:
       hasAttrByPath :: [String] -> AttrSet -> Bool
@@ -80,6 +87,71 @@ rec {
     in
       hasAttrByPath' 0 e;
 
+  /*
+    Return the longest prefix of an attribute path that refers to an existing attribute in a nesting of attribute sets.
+
+    Can be used after [`mapAttrsRecursiveCond`](#function-library-lib.attrsets.mapAttrsRecursiveCond) to apply a condition,
+    although this will evaluate the predicate function on sibling attributes as well.
+
+    Note that the empty attribute path is valid for all values, so this function only throws an exception if any of its inputs does.
+
+    **Laws**:
+    1.  ```nix
+        attrsets.longestValidPathPrefix [] x == []
+        ```
+
+    2.  ```nix
+        hasAttrByPath (attrsets.longestValidPathPrefix p x) x == true
+        ```
+
+    Example:
+      x = { a = { b = 3; }; }
+      attrsets.longestValidPathPrefix ["a" "b" "c"] x
+      => ["a" "b"]
+      attrsets.longestValidPathPrefix ["a"] x
+      => ["a"]
+      attrsets.longestValidPathPrefix ["z" "z"] x
+      => []
+      attrsets.longestValidPathPrefix ["z" "z"] (throw "no need")
+      => []
+
+    Type:
+      attrsets.longestValidPathPrefix :: [String] -> Value -> [String]
+  */
+  longestValidPathPrefix =
+    # A list of strings representing the longest possible path that may be returned.
+    attrPath:
+    # The nested attribute set to check.
+    v:
+    let
+      lenAttrPath = length attrPath;
+      getPrefixForSetAtIndex =
+        # The nested attribute set to check, if it is an attribute set, which
+        # is not a given.
+        remainingSet:
+        # The index of the attribute we're about to check, as well as
+        # the length of the prefix we've already checked.
+        remainingPathIndex:
+
+          if remainingPathIndex == lenAttrPath then
+            # All previously checked attributes exist, and no attr names left,
+            # so we return the whole path.
+            attrPath
+          else
+            let
+              attr = elemAt attrPath remainingPathIndex;
+            in
+            if remainingSet ? ${attr} then
+              getPrefixForSetAtIndex
+                remainingSet.${attr}      # advance from the set to the attribute value
+                (remainingPathIndex + 1)  # advance the path
+            else
+              # The attribute doesn't exist, so we return the prefix up to the
+              # previously checked length.
+              take remainingPathIndex attrPath;
+    in
+      getPrefixForSetAtIndex v 0;
+
   /* Create a new attribute set with `value` set at the nested attribute location specified in `attrPath`.
 
      Example:

lib/flake-version-info.nix

@@ -0,0 +1,20 @@
+# This function produces a lib overlay to be used by the nixpkgs
+# & nixpkgs/lib flakes to provide meaningful values for
+# `lib.trivial.version` et al..
+#
+# Internal and subject to change, don't use this anywhere else!
+# Instead, consider using a public interface, such as this flake here
+# in this directory, `lib/`, or use the nixpkgs flake, which applies
+# this logic for you in its `lib` output attribute.
+
+self: # from the flake
+
+finalLib: prevLib: # lib overlay
+
+{
+  trivial = prevLib.trivial // {
+    versionSuffix =
+      ".${finalLib.substring 0 8 (self.lastModifiedDate or "19700101")}.${self.shortRev or "dirty"}";
+    revisionWithDefault = default: self.rev or default;
+  };
+}

lib/flake.nix

@@ -1,5 +1,10 @@
 {
   description = "Library of low-level helper functions for nix expressions.";
 
-  outputs = { self }: { lib = import ./.; };
+  outputs = { self }:
+    let
+      lib0 = import ./.;
+    in {
+      lib = lib0.extend (import ./flake-version-info.nix self);
+    };
 }

lib/strings.nix

@@ -715,12 +715,12 @@ rec {
        getName pkgs.youtube-dl
        => "youtube-dl"
   */
-  getName = x:
-   let
-     parse = drv: (parseDrvName drv).name;
-   in if isString x
-      then parse x
-      else x.pname or (parse x.name);
+  getName = let
+    parse = drv: (parseDrvName drv).name;
+  in x:
+    if isString x
+    then parse x
+    else x.pname or (parse x.name);
 
   /* This function takes an argument that's either a derivation or a
      derivation's "name" attribute and extracts the version part from that
@@ -732,12 +732,12 @@ rec {
        getVersion pkgs.youtube-dl
        => "2016.01.01"
   */
-  getVersion = x:
-   let
-     parse = drv: (parseDrvName drv).version;
-   in if isString x
-      then parse x
-      else x.version or (parse x.name);
+  getVersion = let
+    parse = drv: (parseDrvName drv).version;
+  in x:
+    if isString x
+    then parse x
+    else x.version or (parse x.name);
 
   /* Extract name with version from URL. Ask for separator which is
      supposed to start extension.
@@ -771,12 +771,13 @@ rec {
        cmakeOptionType "string" "ENGINE" "sdl2"
        => "-DENGINE:STRING=sdl2"
   */
-  cmakeOptionType = type: feature: value:
-    assert (lib.elem (lib.toUpper type)
-      [ "BOOL" "FILEPATH" "PATH" "STRING" "INTERNAL" ]);
-    assert (lib.isString feature);
-    assert (lib.isString value);
-    "-D${feature}:${lib.toUpper type}=${value}";
+  cmakeOptionType = let
+    types = [ "BOOL" "FILEPATH" "PATH" "STRING" "INTERNAL" ];
+  in type: feature: value:
+    assert (elem (toUpper type) types);
+    assert (isString feature);
+    assert (isString value);
+    "-D${feature}:${toUpper type}=${value}";
 
   /* Create a -D<condition>={TRUE,FALSE} string that can be passed to typical
      CMake invocations.
@@ -977,9 +978,11 @@ rec {
      Many types of value are coercible to string this way, including int, float,
      null, bool, list of similarly coercible values.
   */
-  isConvertibleWithToString = x:
+  isConvertibleWithToString = let
+    types = [ "null" "int" "float" "bool" ];
+  in x:
     isStringLike x ||
-    elem (typeOf x) [ "null" "int" "float" "bool" ] ||
+    elem (typeOf x) types ||
     (isList x && lib.all isConvertibleWithToString x);
 
   /* Check whether a value can be coerced to a string.

lib/tests/misc.nix

@@ -697,6 +697,51 @@ runTests {
     expected = false;
   };
 
+  testHasAttrByPathNonStrict = {
+    expr = hasAttrByPath [] (throw "do not use");
+    expected = true;
+  };
+
+  testLongestValidPathPrefix_empty_empty = {
+    expr = attrsets.longestValidPathPrefix [ ] { };
+    expected = [ ];
+  };
+
+  testLongestValidPathPrefix_empty_nonStrict = {
+    expr = attrsets.longestValidPathPrefix [ ] (throw "do not use");
+    expected = [ ];
+  };
+
+  testLongestValidPathPrefix_zero = {
+    expr = attrsets.longestValidPathPrefix [ "a" (throw "do not use") ] { d = null; };
+    expected = [ ];
+  };
+
+  testLongestValidPathPrefix_zero_b = {
+    expr = attrsets.longestValidPathPrefix [ "z" "z" ] "remarkably harmonious";
+    expected = [ ];
+  };
+
+  testLongestValidPathPrefix_one = {
+    expr = attrsets.longestValidPathPrefix [ "a" "b" "c" ] { a = null; };
+    expected = [ "a" ];
+  };
+
+  testLongestValidPathPrefix_two = {
+    expr = attrsets.longestValidPathPrefix [ "a" "b" "c" ] { a.b = null; };
+    expected = [ "a" "b" ];
+  };
+
+  testLongestValidPathPrefix_three = {
+    expr = attrsets.longestValidPathPrefix [ "a" "b" "c" ] { a.b.c = null; };
+    expected = [ "a" "b" "c" ];
+  };
+
+  testLongestValidPathPrefix_three_extra = {
+    expr = attrsets.longestValidPathPrefix [ "a" "b" "c" ] { a.b.c.d = throw "nope"; };
+    expected = [ "a" "b" "c" ];
+  };
+
   testFindFirstIndexExample1 = {
     expr = lists.findFirstIndex (x: x > 3) (abort "index found, so a default must not be evaluated") [ 1 6 4 ];
     expected = 1;

lib/trivial.nix

@@ -1,6 +1,18 @@
 { lib }:
 
-rec {
+let
+  inherit (lib.trivial)
+    isFunction
+    isInt
+    functionArgs
+    pathExists
+    release
+    setFunctionArgs
+    toBaseDigits
+    version
+    versionSuffix
+    warn;
+in {
 
   ## Simple (higher order) functions
 
@@ -58,9 +70,7 @@ rec {
      of the next function, and the last function returns the
      final value.
   */
-  pipe = val: functions:
-    let reverseApply = x: f: f x;
-    in builtins.foldl' reverseApply val functions;
+  pipe = builtins.foldl' (x: f: f x);
 
   # note please don’t add a function like `compose = flip pipe`.
   # This would confuse users, because the order of the functions
@@ -439,7 +449,7 @@ rec {
   */
   functionArgs = f:
     if f ? __functor
-    then f.__functionArgs or (lib.functionArgs (f.__functor f))
+    then f.__functionArgs or (functionArgs (f.__functor f))
     else builtins.functionArgs f;
 
   /* Check whether something is a function or something
@@ -510,22 +520,20 @@ rec {
 
      toHexString 250 => "FA"
   */
-  toHexString = i:
-    let
-      toHexDigit = d:
-        if d < 10
-        then toString d
-        else
-          {
-            "10" = "A";
-            "11" = "B";
-            "12" = "C";
-            "13" = "D";
-            "14" = "E";
-            "15" = "F";
-          }.${toString d};
-    in
-      lib.concatMapStrings toHexDigit (toBaseDigits 16 i);
+  toHexString = let
+    hexDigits = {
+      "10" = "A";
+      "11" = "B";
+      "12" = "C";
+      "13" = "D";
+      "14" = "E";
+      "15" = "F";
+    };
+    toHexDigit = d:
+      if d < 10
+      then toString d
+      else hexDigits.${toString d};
+  in i: lib.concatMapStrings toHexDigit (toBaseDigits 16 i);
 
   /* `toBaseDigits base i` converts the positive integer i to a list of its
      digits in the given base. For example:

maintainers/maintainer-list.nix

@@ -605,6 +605,12 @@
     githubId = 4717906;
     name = "Jakub Skokan";
   };
+  ajaxbits = {
+    email = "[email protected]";
+    github = "ajaxbits";
+    githubId = 45179933;
+    name = "Alex Jackson";
+  };
   ajgrf = {
     email = "[email protected]";
     github = "ajgrf";

maintainers/team-list.nix

@@ -290,6 +290,7 @@ with lib.maintainers; {
     members = [
       theuni
       dpausp
+      frlan
       leona
     ];
     scope = "Team for Flying Circus employees who collectively maintain packages.";