Merge "feat: add a --priority flag to nix-env --install" into main

doc/manual/change-authors.yml

@@ -36,6 +36,10 @@ alois31:
   forgejo: alois31
   github: alois31
 
+andrewhamon:
+  display_name: Andrew Hamon
+  github: andrewhamon
+
 artemist:
   display_name: Artemis Tosini
   forgejo: artemist

doc/manual/rl-next/nix-env-priority.md

@@ -0,0 +1,25 @@
+---
+synopsis: "`nix-env --install` now accepts a `--priority` flag"
+cls: [2607]
+category: Features
+credits: andrewhamon
+---
+
+`nix-env --install` now has an optional `--priority` flag.
+
+Previously, it was only possible to specify a priority by adding a
+`meta.priority` attribute to a derivation. `meta` attributes only exist during
+eval, so that wouldn't work for installing a store path. It was also possible
+to change a priority after initial installation using `nix-env --set-flag`,
+however if there is already a conflict that needs to be resolved via priorities,
+this will not work.
+
+Now, a priority can be set at install time using `--priority`, which allows for
+cleanly overriding the priority at install time.
+
+#### Example
+
+```console
+$ nix-build
+$ nix-env --install --priority 100 ./result
+```

doc/manual/src/command-ref/nix-env/install.md

@@ -11,6 +11,7 @@
   [`--from-profile` *path*]
   [`--preserve-installed` | `-P`]
   [`--remove-all` | `-r`]
+  [`--priority` *priority*]
 
 # Description
 
@@ -59,6 +60,11 @@ a number of possible ways:
     unambiguous way, which is necessary if there are multiple
     derivations with the same name.
 
+  - If `--priority` *priority* is given, the priority of the derivations being
+    installed is set to *priority*. This can be used to override the priority of
+    the derivations being installed. This is useful if *args* are store paths,
+    which don't have any priority information.
+
   - If *args* are [store derivations](@docroot@/glossary.md#gloss-store-derivation), then these are
     [realised](@docroot@/command-ref/nix-store/realise.md), and the resulting output paths
     are installed.

lix/legacy/nix-env.cc

@@ -513,9 +513,16 @@ static bool keep(EvalState & state, DrvInfo & drv)
     return drv.queryMetaBool(state, "keep", false);
 }
 
+static void setMetaFlag(EvalState & state, DrvInfo & drv,
+    const std::string & name, const std::string & value)
+{
+    auto v = state.ctx.mem.allocValue();
+    v->mkString(value);
+    drv.setMeta(state, name, v);
+}
 
 static void installDerivations(Globals & globals,
-    const Strings & args, const Path & profile)
+    const Strings & args, const Path & profile, std::optional<int> priority)
 {
     debug("installing derivations");
 
@@ -541,6 +548,11 @@ static void installDerivations(Globals & globals,
         newNames.insert(DrvName(i.queryName(*state)).name);
     }
 
+    if (priority) {
+        for (auto & drv : newElems) {
+            setMetaFlag(*state, drv, "priority", std::to_string((priority.value())));
+        }
+    }
 
     while (true) {
         auto lockToken = optimisticLockProfile(profile);
@@ -578,6 +590,7 @@ static void installDerivations(Globals & globals,
 
 static void opInstall(Globals & globals, Strings opFlags, Strings opArgs)
 {
+    std::optional<int> priority;
     for (Strings::iterator i = opFlags.begin(); i != opFlags.end(); ) {
         auto arg = *i++;
         if (parseInstallSourceOptions(globals, i, opFlags, arg)) ;
@@ -585,10 +598,17 @@ static void opInstall(Globals & globals, Strings opFlags, Strings opArgs)
             globals.preserveInstalled = true;
         else if (arg == "--remove-all" || arg == "-r")
             globals.removeAll = true;
+        else if (arg == "--priority") {
+            if (i == opFlags.end())
+                throw UsageError("'%1%' requires an argument", arg);
+            priority = string2Int<int>(*i++);
+            if (!priority)
+                throw UsageError("'--priority' requires an integer argument");
+        }
         else throw UsageError("unknown flag '%1%'", arg);
     }
 
-    installDerivations(globals, opArgs, globals.profile);
+    installDerivations(globals, opArgs, globals.profile, priority);
 }
 
 
@@ -705,15 +725,6 @@ static void opUpgrade(Globals & globals, Strings opFlags, Strings opArgs)
 }
 
 
-static void setMetaFlag(EvalState & state, DrvInfo & drv,
-    const std::string & name, const std::string & value)
-{
-    auto v = state.ctx.mem.allocValue();
-    v->mkString(value);
-    drv.setMeta(state, name, v);
-}
-
-
 static void opSetFlag(Globals & globals, Strings opFlags, Strings opArgs)
 {
     if (opFlags.size() > 0)
@@ -1523,7 +1534,8 @@ static int main_nix_env(AsyncIoRoot & aio, std::string programName, Strings argv
                 opFlags.push_back(*arg);
                 /* FIXME: hacky */
                 if (*arg == "--from-profile" ||
-                    (op == opQuery && (*arg == "--attr" || *arg == "-A")))
+                    (op == opQuery && (*arg == "--attr" || *arg == "-A")) ||
+                    (op == opInstall && (*arg == "--priority")))
                     opFlags.push_back(getArg(*arg, arg, end));
             }
             else

tests/functional/user-envs.sh

@@ -177,13 +177,21 @@ nix-env -q '*' | grepQuiet bar-0.1.1
 
 # Test priorities: foo-0.1 has a lower priority than foo-1.0, so it
 # should be possible to install both without a collision.  Also test
-# ‘--set-flag priority’ to manually override the declared priorities.
+# '-i --priority' and  '--set-flag priority' to manually override the
+# declared priorities.
 nix-env -e '*'
 nix-env -i foo-0.1 foo-1.0
 [ "$($profiles/test/bin/foo)" = "foo-1.0" ]
 nix-env --set-flag priority 1 foo-0.1
 [ "$($profiles/test/bin/foo)" = "foo-0.1" ]
 
+# Priorities can be overridden with the --priority flag
+nix-env -e '*'
+nix-env -i foo-1.0
+[ "$($profiles/test/bin/foo)" = "foo-1.0" ]
+nix-env -i --priority 1 foo-0.1
+[ "$($profiles/test/bin/foo)" = "foo-0.1" ]
+
 # Test nix-env --set.
 nix-env --set $outPath10
 [ "$(nix-store -q --resolve $profiles/test)" = $outPath10 ]