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doc/functions/debug.section.md

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+# Debugging Nix Expressions {#sec-debug}
+
+Nix is a unityped, dynamic language, this means any value can potentially appear anywhere. Since it is also non-strict, evaluation order and what is ultimately evaluated might surprise you. Therefore, it is important to be able to debug Nix expressions.
+
+In the `lib/debug.nix` file you will find a number of functions that help (pretty-)printing values while evaluation is running. You can even specify how deep these values should be printed recursively, and transform them on the fly. Please consult the docstrings in `lib/debug.nix` for usage information.

doc/functions/generators.section.md

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+# Generators {#sec-generators}
+Generators are functions that create file formats from Nix data structures, e.g. for configuration files. There are generators available for: `INI`, `JSON` and `YAML`.
+
+All generators follow a similar call interface: `generatorName configFunctions data`, where `configFunctions` is an attrset of user-defined functions that format nested parts of the content. They each have common defaults, so often they do not need to be set manually. An example is `mkSectionName` from the `INI` generator, which defaults to `(name: libStr.escape [ "[" "]" ] name)`. It receives the name of a section and sanitizes it. The default `mkSectionName` escapes `[` and `]` with a backslash.
+
+Generators can be fine-tuned to produce exactly the file format required by your application/service. One example is an INI file format that uses `: ` as a separator, the strings `"yes"` and `"no"` as boolean values, and requires all string values to be quoted:
+
+```nix
+let
+  inherit (lib) generators isString;
+
+  customToINI = generators.toINI {
+    # specifies how to format a key/value pair
+    mkKeyValue = generators.mkKeyValueDefault {
+      # specifies the generated string for a subset of nix values
+      mkValueString =
+        v:
+        if v == true then
+          ''"yes"''
+        else if v == false then
+          ''"no"''
+        else if isString v then
+          ''"${v}"''
+        # and delegates all other values to the default generator
+        else
+          generators.mkValueStringDefault { } v;
+    } ":";
+  };
+
+  # the INI file can now be given as plain old nix values
+in
+customToINI {
+  main = {
+    pushinfo = true;
+    autopush = false;
+    host = "localhost";
+    port = 42;
+  };
+  mergetool = {
+    merge = "diff3";
+  };
+}
+```
+
+This will produce the following INI file as a Nix string:
+
+```INI
+[main]
+autopush:"no"
+host:"localhost"
+port:42
+pushinfo:"yes"
+str\:ange:"very::strange"
+
+[mergetool]
+merge:"diff3"
+```
+
+::: {.note}
+Nix store paths can be converted to strings by enclosing a derivation attribute like so: `"${drv}"`.
+:::
+
+Detailed documentation for each generator can be found [here](#sec-functions-library-generators)

doc/functions/library.md.in

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+# Nixpkgs Library Functions {#sec-functions-library}
+
+Nixpkgs provides a standard library at `pkgs.lib`, or through `import <nixpkgs/lib>`.
+
+<!-- nixdoc-generated documentation must be appended here during build! -->

doc/functions/nix-gitignore.section.md

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+# pkgs.nix-gitignore {#sec-pkgs-nix-gitignore}
+
+`pkgs.nix-gitignore` is a function that acts similarly to `builtins.filterSource` but also allows filtering with the help of the gitignore format.
+
+## Usage {#sec-pkgs-nix-gitignore-usage}
+
+`pkgs.nix-gitignore` exports a number of functions, but you'll most likely need either `gitignoreSource` or `gitignoreSourcePure`. As their first argument, they both accept either 1. a file with gitignore lines or 2. a string with gitignore lines, or 3. a list of either of the two. They will be concatenated into a single big string.
+
+```nix
+{
+  pkgs ? import <nixpkgs> { },
+}:
+{
+
+  src = nix-gitignore.gitignoreSource [ ] ./source;
+  # Simplest version
+
+  src = nix-gitignore.gitignoreSource ''
+    supplemental-ignores
+  '' ./source;
+  # This one reads the ./source/.gitignore and concats the auxiliary ignores
+
+  src = nix-gitignore.gitignoreSourcePure ''
+    ignore-this
+    ignore-that
+  '' ./source;
+  # Use this string as gitignore, don't read ./source/.gitignore.
+
+  src = nix-gitignore.gitignoreSourcePure [
+    ''
+      ignore-this
+      ignore-that
+    ''
+    ~/.gitignore
+  ] ./source;
+  # It also accepts a list (of strings and paths) that will be concatenated
+  # once the paths are turned to strings via readFile.
+}
+```
+
+These functions are derived from the `Filter` functions by setting the first filter argument to `(_: _: true)`:
+
+```nix
+{
+  gitignoreSourcePure = gitignoreFilterSourcePure (_: _: true);
+  gitignoreSource = gitignoreFilterSource (_: _: true);
+}
+```
+
+Those filter functions accept the same arguments the `builtins.filterSource` function would pass to its filters, thus `fn: gitignoreFilterSourcePure fn ""` should be extensionally equivalent to `filterSource`. The file is blacklisted if it's blacklisted by either your filter or the gitignoreFilter.
+
+If you want to make your own filter from scratch, you may use
+
+```nix
+{ gitignoreFilter = ign: root: filterPattern (gitignoreToPatterns ign) root; }
+```
+
+## gitignore files in subdirectories {#sec-pkgs-nix-gitignore-usage-recursive}
+
+If you wish to use a filter that would search for .gitignore files in subdirectories, just like git does by default, use this function:
+
+```nix
+{
+  # gitignoreFilterRecursiveSource = filter: patterns: root:
+  # OR
+  gitignoreRecursiveSource = gitignoreFilterSourcePure (_: _: true);
+}
+```

doc/functions/prefer-remote-fetch.section.md

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+# prefer-remote-fetch overlay {#sec-prefer-remote-fetch}
+
+`prefer-remote-fetch` is an overlay that downloads sources on a remote builder. This is useful when the evaluating machine has a slow upload while the builder can fetch faster, directly from the source. To use it, put the following snippet as a new overlay:
+
+```nix
+self: super: (super.prefer-remote-fetch self super)
+```
+
+A full configuration example that sets the overlay up for your own account could look like this
+
+```ShellSession
+$ mkdir ~/.config/nixpkgs/overlays/
+$ cat > ~/.config/nixpkgs/overlays/prefer-remote-fetch.nix <<EOF
+  self: super: super.prefer-remote-fetch self super
+EOF
+```