git: support nested section options

Closes #614

modules/programs/git.nix

@@ -6,6 +6,19 @@ let
 
   cfg = config.programs.git;
 
+  # create [section "subsection"] keys from "section.subsection" attrset names
+  mkSectionName = name:
+    let
+      containsQuote = strings.hasInfix ''"'' name;
+      sections = splitString "." name;
+      section = head sections;
+      subsections = tail sections;
+      subsection = concatStringsSep "." subsections;
+    in
+      if containsQuote || subsections == []
+      then name
+      else "${section} \"${subsection}\"";
+
   # generation for multiple ini values
   mkKeyValue = k: v:
     let
@@ -13,15 +26,33 @@ let
     in
       concatStringsSep "\n" (map mkKeyValue (toList v));
 
-  gitToIni = generators.toINI { inherit mkKeyValue; };
+  # converts { a.b.c = 5; } to { "a.b".c = 5; } for toINI
+  gitFlattenAttrs =
+    let
+      recurse = path: value:
+        if isAttrs value then
+          mapAttrsToList (name: value: recurse ([name] ++ path) value) value
+        else if length path > 1 then
+          { ${concatStringsSep "." (reverseList (tail path))}.${head path} = value; }
+        else
+          { ${head path} = value; };
+    in
+      attrs: foldl recursiveUpdate {} (flatten (recurse [] attrs));
+
+  gitToIni = attrs:
+    let
+      toIni = generators.toINI { inherit mkKeyValue mkSectionName; };
+    in
+      toIni (gitFlattenAttrs attrs);
 
   gitIniType = with types;
     let
       primitiveType = either str (either bool int);
       multipleType = either primitiveType (listOf primitiveType);
       sectionType = attrsOf multipleType;
+      supersectionType = attrsOf (either multipleType sectionType);
     in
-      attrsOf sectionType;
+      attrsOf supersectionType;
 
   signModule = types.submodule {
     options = {
@@ -128,6 +159,7 @@ in
         default = {};
         example = {
           core = { whitespace = "trailing-space,space-before-tab"; };
+          url."ssh://git@host".insteadOf = "otherhost";
         };
         description = "Additional configuration to add.";
       };
@@ -200,7 +232,7 @@ in
             hasSmtp = name: account: account.smtp != null;
 
             genIdentity = name: account: with account;
-              nameValuePair "sendemail \"${name}\"" ({
+              nameValuePair "sendemail.${name}" ({
                 smtpEncryption = if smtp.tls.enable then "tls" else "";
                 smtpServer = smtp.host;
                 smtpUser = userName;
@@ -235,19 +267,23 @@ in
       })
 
       (mkIf (cfg.includes != []) {
-        xdg.configFile."git/config".text = mkAfter
-          (concatMapStringsSep "\n"
-            (i: with i; ''
-              [${if (condition == null) then "include" else "includeIf \"${condition}\""}]
-              path = ${path}
-            '')
-            cfg.includes);
+        xdg.configFile."git/config".text =
+          let
+            include = i: with i;
+              if condition != null
+              then { includeIf.${condition}.path = "${path}"; }
+              else { include.path = "${path}"; };
+          in
+            mkAfter
+            (concatStringsSep "\n"
+            (map gitToIni
+            (map include cfg.includes)));
       })
 
       (mkIf cfg.lfs.enable {
         home.packages = [ pkgs.git-lfs ];
 
-        programs.git.iniContent."filter \"lfs\"" =
+        programs.git.iniContent.filter.lfs =
           let
             skipArg = optional cfg.lfs.skipSmudge "--skip";
           in

tests/modules/programs/git-expected.conf

@@ -12,6 +12,12 @@ multiple=1
 multiple=2
 name=value
 
+[extra "backcompat.with.dots"]
+previously=worked
+
+[extra "subsection"]
+value=test
+
 [filter "lfs"]
 clean=git-lfs clean -- %f
 process=git-lfs filter-process
@@ -27,10 +33,10 @@ name=John Doe
 signingKey=00112233445566778899AABBCCDDEEFF
 
 [include]
-path = ~/path/to/config.inc
+path=~/path/to/config.inc
 
 [includeIf "gitdir:~/src/dir"]
-path = ~/path/to/conditional.inc
+path=~/path/to/conditional.inc
 
 [includeIf "gitdir:~/src/dir"]
-path = @git_include_path@
+path=@git_include_path@

tests/modules/programs/git.nix

@@ -58,9 +58,11 @@ in
 
       {
         aliases.a2 = mkForce "baz";
+        extraConfig."extra \"backcompat.with.dots\"".previously = "worked";
         extraConfig.extra.boolean = true;
         extraConfig.extra.integer = 38;
         extraConfig.extra.multiple = [2];
+        extraConfig.extra.subsection.value = "test";
       }
     ];