Merge remote-tracking branch 'upstream/master' into trustless-remote-builder-simple

6 files changed, 74 insertions, 28 deletions

diff --git a/doc/manual/generate-manpage.nix b/doc/manual/generate-manpage.nix
index 86f2ca567..d04eecf55 100644
--- a/doc/manual/generate-manpage.nix
+++ b/doc/manual/generate-manpage.nix
@@ -10,7 +10,9 @@ let
 
       result = ''
         > **Warning** \
-        > This program is **experimental** and its interface is subject to change.
+        > This program is
+        > [**experimental**](@docroot@/contributing/experimental-features.md#xp-feature-nix-command)
+        > and its interface is subject to change.
 
         # Name
 
@@ -29,19 +31,18 @@ let
 
       showSynopsis = command: args:
         let
-          showArgument = arg: "*${arg.label}*" + (if arg ? arity then "" else "...");
+          showArgument = arg: "*${arg.label}*" + optionalString (! arg ? arity) "...";
           arguments = concatStringsSep " " (map showArgument args);
         in ''
          `${command}` [*option*...] ${arguments}
         '';
 
-      maybeSubcommands = if details ? commands && details.commands != {}
-        then ''
+      maybeSubcommands = optionalString (details ? commands && details.commands != {})
+         ''
            where *subcommand* is one of the following:
 
            ${subcommands}
-         ''
-        else "";
+         '';
 
       subcommands = if length categories > 1
         then listCategories
@@ -63,12 +64,11 @@ let
         * [`${command} ${name}`](./${appendName filename name}.md) - ${subcmd.description}
       '';
 
-      maybeDocumentation =
-        if details ? doc
-        then replaceStrings ["@stores@"] [storeDocs] details.doc
-        else "";
+      maybeDocumentation = optionalString
+        (details ? doc)
+        (replaceStrings ["@stores@"] [storeDocs] details.doc);
 
-      maybeOptions = if details.flags == {} then "" else ''
+      maybeOptions = optionalString (details.flags != {}) ''
         # Options
 
         ${showOptions details.flags toplevel.flags}
@@ -78,15 +78,19 @@ let
         let
           allOptions = options // commonOptions;
           showCategory = cat: ''
-            ${if cat != "" then "**${cat}:**" else ""}
+            ${optionalString (cat != "") "**${cat}:**"}
 
             ${listOptions (filterAttrs (n: v: v.category == cat) allOptions)}
             '';
           listOptions = opts: concatStringsSep "\n" (attrValues (mapAttrs showOption opts));
           showOption = name: option:
             let
-              shortName = if option ? shortName then "/ `-${option.shortName}`" else "";
-              labels = if option ? labels then (concatStringsSep " " (map (s: "*${s}*") option.labels)) else "";
+              shortName = optionalString
+                (option ? shortName)
+                ("/ `-${option.shortName}`");
+              labels = optionalString
+                (option ? labels)
+                (concatStringsSep " " (map (s: "*${s}*") option.labels));
             in trim ''
               - `--${name}` ${shortName} ${labels}
 
diff --git a/doc/manual/src/command-ref/experimental-commands.md b/doc/manual/src/command-ref/experimental-commands.md
index cfa6f8b73..286ddc6d6 100644
--- a/doc/manual/src/command-ref/experimental-commands.md
+++ b/doc/manual/src/command-ref/experimental-commands.md
@@ -1,6 +1,6 @@
 # Experimental Commands
 
-This section lists experimental commands.
+This section lists [experimental commands](@docroot@/contributing/experimental-features.md#xp-feature-nix-command).
 
 > **Warning**
 >
diff --git a/doc/manual/src/glossary.md b/doc/manual/src/glossary.md
index 4eedb2e93..a9782be5c 100644
--- a/doc/manual/src/glossary.md
+++ b/doc/manual/src/glossary.md
@@ -225,3 +225,9 @@
     [string]: ./language/values.md#type-string
     [path]: ./language/values.md#type-path
     [attribute name]: ./language/values.md#attribute-set
+
+  - [experimental feature]{#gloss-experimental-feature}\
+    Not yet stabilized functionality guarded by named experimental feature flags.
+    These flags are enabled or disabled with the [`experimental-features`](./command-ref/conf-file.html#conf-experimental-features) setting.
+
+    See the contribution guide on the [purpose and lifecycle of experimental feaures](@docroot@/contributing/experimental-features.md).
diff --git a/doc/manual/src/language/advanced-attributes.md b/doc/manual/src/language/advanced-attributes.md
index 3e8c48890..307971434 100644
--- a/doc/manual/src/language/advanced-attributes.md
+++ b/doc/manual/src/language/advanced-attributes.md
@@ -208,12 +208,26 @@ Derivations can declare some infrequently used optional attributes.
     about converting to and from base-32 notation.)
 
   - [`__contentAddressed`]{#adv-attr-__contentAddressed}
-    If this **experimental** attribute is set to true, then the derivation
+    > **Warning**
+    > This attribute is part of an [experimental feature](@docroot@/contributing/experimental-features.md).
+    >
+    > To use this attribute, you must enable the
+    > [`ca-derivations`](@docroot@/contributing/experimental-features.md#xp-feature-ca-derivations) experimental feature.
+    > For example, in [nix.conf](../command-ref/conf-file.md) you could add:
+    >
+    > ```
+    > extra-experimental-features = ca-derivations
+    > ```
+
+    If this attribute is set to `true`, then the derivation
     outputs will be stored in a content-addressed location rather than the
     traditional input-addressed one.
-    This only has an effect if the `ca-derivations` experimental feature is enabled.
 
-    Setting this attribute also requires setting `outputHashMode` and `outputHashAlgo` like for *fixed-output derivations* (see above).
+    Setting this attribute also requires setting
+    [`outputHashMode`](#adv-attr-outputHashMode)
+    and
+    [`outputHashAlgo`](#adv-attr-outputHashAlgo)
+    like for *fixed-output derivations* (see above).
 
   - [`passAsFile`]{#adv-attr-passAsFile}\
     A list of names of attributes that should be passed via files rather
@@ -307,9 +321,11 @@ Derivations can declare some infrequently used optional attributes.
 
   - [`unsafeDiscardReferences`]{#adv-attr-unsafeDiscardReferences}\
     > **Warning**
-    > This is an experimental feature.
+    > This attribute is part of an [experimental feature](@docroot@/contributing/experimental-features.md).
     >
-    > To enable it, add the following to [nix.conf](../command-ref/conf-file.md):
+    > To use this attribute, you must enable the
+    > [`discard-references`](@docroot@/contributing/experimental-features.md#xp-feature-discard-references) experimental feature.
+    > For example, in [nix.conf](../command-ref/conf-file.md) you could add:
     >
     > ```
     > extra-experimental-features = discard-references
diff --git a/doc/manual/src/quick-start.md b/doc/manual/src/quick-start.md
index 651134c25..1d2688ede 100644
--- a/doc/manual/src/quick-start.md
+++ b/doc/manual/src/quick-start.md
@@ -19,7 +19,7 @@ to subsequent chapters.
    channel:
 
    ```console
-   $ nix-env -qaP
+   $ nix-env --query --available --attr-path
    nixpkgs.docbook_xml_dtd_43                    docbook-xml-4.3
    nixpkgs.docbook_xml_dtd_45                    docbook-xml-4.5
    nixpkgs.firefox                               firefox-33.0.2
@@ -31,7 +31,7 @@ to subsequent chapters.
 1. Install some packages from the channel:
 
    ```console
-   $ nix-env -iA nixpkgs.hello
+   $ nix-env --install --attr nixpkgs.hello
    ```
 
    This should download pre-built packages; it should not build them
@@ -49,13 +49,13 @@ to subsequent chapters.
 1. Uninstall a package:
 
    ```console
-   $ nix-env -e hello
+   $ nix-env --uninstall hello
    ```
 
 1. You can also test a package without installing it:
 
    ```console
-   $ nix-shell -p hello
+   $ nix-shell --packages hello
    ```
 
    This builds or downloads GNU Hello and its dependencies, then drops
@@ -76,7 +76,7 @@ to subsequent chapters.
 
    ```console
    $ nix-channel --update nixpkgs
-   $ nix-env -u '*'
+   $ nix-env --upgrade '*'
    ```
 
    The latter command will upgrade each installed package for which
@@ -95,5 +95,5 @@ to subsequent chapters.
    them:
 
    ```console
-   $ nix-collect-garbage -d
+   $ nix-collect-garbage --delete-old
    ```
diff --git a/doc/manual/utils.nix b/doc/manual/utils.nix
index 82544935a..9043dd8cd 100644
--- a/doc/manual/utils.nix
+++ b/doc/manual/utils.nix
@@ -42,7 +42,9 @@ rec {
   filterAttrs = pred: set:
     listToAttrs (concatMap (name: let v = set.${name}; in if pred name v then [(nameValuePair name v)] else []) (attrNames set));
 
-  showSetting = { useAnchors }: name: { description, documentDefault, defaultValue, aliases, value }:
+  optionalString = cond: string: if cond then string else "";
+
+  showSetting = { useAnchors }: name: { description, documentDefault, defaultValue, aliases, value, experimentalFeature }:
     let
       result = squash ''
           - ${if useAnchors
@@ -52,10 +54,28 @@ rec {
           ${indent "  " body}
         '';
 
+      experimentalFeatureNote = optionalString (experimentalFeature != null) ''
+          > **Warning**
+          > This setting is part of an
+          > [experimental feature](@docroot@/contributing/experimental-features.md).
+
+          To change this setting, you need to make sure the corresponding experimental feature,
+          [`${experimentalFeature}`](@docroot@/contributing/experimental-features.md#xp-feature-${experimentalFeature}),
+          is enabled.
+          For example, include the following in [`nix.conf`](#):
+
+          ```
+          extra-experimental-features = ${experimentalFeature}
+          ${name} = ...
+          ```
+        '';
+
       # separate body to cleanly handle indentation
       body = ''
           ${description}
 
+          ${experimentalFeatureNote}
+
           **Default:** ${showDefault documentDefault defaultValue}
 
           ${showAliases aliases}
@@ -74,7 +94,7 @@ rec {
         else "*machine-specific*";
 
       showAliases = aliases:
-          if aliases == [] then "" else
+          optionalString (aliases != [])
             "**Deprecated alias:** ${(concatStringsSep ", " (map (s: "`${s}`") aliases))}";
 
     in result;