populate: deliver flakes and draw inputs with the Rust program

The program delivers flake and flake-input sources, draws inputs from
sources, and removes state that sources don't need anymore, so it does
everything the shell implementation does, and passes all scenarios.
src/flake.rs builds the same shell code as shell.nix generates for
these, with every value quoted, so both implementations behave alike
while that code moves to Rust piece by piece.

The ssh scripts in the temporary directory run the ssh that was in PATH
when populate started, so one can be ssh in PATH for nix copy.  The
other one is for nix copy's ssh:// store, without the control socket.

1 files changed, 22 insertions, 22 deletions

diff --git a/pkgs/populate/src/populate.rs b/pkgs/populate/src/populate.rs
index d3567d3..ef806b0 100644
--- a/pkgs/populate/src/populate.rs
+++ b/pkgs/populate/src/populate.rs
@@ -1,5 +1,6 @@
 //! Delivering the sources of a spec.
 
+use crate::flake;
 use crate::rsync::{self, Config};
 use crate::run::{self, Context, Failure, Result};
 use crate::sh;
@@ -13,7 +14,7 @@ use std::process::Command;
 /// prunes if asked.
 pub fn populate(context: &Context, spec: &Spec) -> Result<()> {
     let dir = &spec.target.path;
-    unsupported(context, spec)?;
+    refuse_copying_with_sudo(context, spec)?;
     let sentinel = format!("{dir}/.populate");
     let force = if spec.force { "1" } else { "" };
     context.run(
@@ -30,8 +31,9 @@ pub fn populate(context: &Context, spec: &Spec) -> Result<()> {
         fs::create_dir_all(&workdir).map_err(|e| {
             Failure::Message(format!("error: can't create {}: {e}", workdir.display()))
         })?;
-        deliver(context, source, &path, workdir)?;
+        deliver(context, name, source, &path, workdir)?;
     }
+    context.run(&flake::flakes(context, dir, &spec.source), &[])?;
     if spec.prune {
         let flakes = spec
             .source
@@ -49,9 +51,10 @@ pub fn populate(context: &Context, spec: &Spec) -> Result<()> {
     Ok(())
 }
 
-/// Fails, before changing anything, if the spec needs what this program
-/// doesn't do yet.
-fn unsupported(context: &Context, spec: &Spec) -> Result<()> {
+/// Fails, before changing anything, if flakes would get copied to a remote
+/// target using sudo, which nix copy doesn't support: it logs in as the
+/// target's user.
+fn refuse_copying_with_sudo(context: &Context, spec: &Spec) -> Result<()> {
     for (name, source) in &spec.source {
         let copying = matches!(source.kind.as_str(), "flake" | "flake-input")
             && source
@@ -66,21 +69,6 @@ fn unsupported(context: &Context, spec: &Spec) -> Result<()> {
             )));
         }
     }
-    for source in spec.source.values() {
-        let what = match source.kind.as_str() {
-            "derivation" | "file" | "git" | "pass" | "passage" | "pipe" | "symlink" => None,
-            kind => Some(format!("{kind} sources")),
-        };
-        let what = what.or_else(|| {
-            (!source.follows().is_empty()).then(|| "drawing inputs from sources".to_string())
-        });
-        if let Some(what) = what {
-            return Err(Failure::Message(format!(
-                "populate: {what} aren't implemented yet, so it delivers nothing to {}",
-                context.name(&spec.target.path)
-            )));
-        }
-    }
     Ok(())
 }
 
@@ -93,7 +81,13 @@ fn string<'a>(settings: &'a Map<String, Value>, key: &str) -> Result<&'a str> {
 
 /// Delivers a source to path on the target, using workdir for files it
 /// prepares on the deploying machine.
-fn deliver(context: &Context, source: &Source, path: &str, workdir: PathBuf) -> Result<()> {
+fn deliver(
+    context: &Context,
+    name: &str,
+    source: &Source,
+    path: &str,
+    workdir: PathBuf,
+) -> Result<()> {
     let settings = &source.settings;
     match source.kind.as_str() {
         "derivation" => context.run(
@@ -138,6 +132,11 @@ fn deliver(context: &Context, source: &Source, path: &str, workdir: PathBuf) ->
             };
             rsync::transfer(context, &config, &out.to_string_lossy(), path)
         }
+        "flake" | "flake-input" => run::status(&mut run::local_shell(
+            &flake::flake_input(context, name, path, source),
+            &[],
+            &workdir,
+        )),
         "git" => {
             let flag = |key| match settings.get(key).and_then(Value::as_bool) {
                 Some(true) => "1",
@@ -209,8 +208,9 @@ fn deliver(context: &Context, source: &Source, path: &str, workdir: PathBuf) ->
             )
         }
         "symlink" => context.run(sh::SYMLINK, &[path, string(settings, "target")?]),
+        // The spec's types are all of the above.
         kind => Err(Failure::Message(format!(
-            "populate: {kind} sources aren't implemented yet"
+            "populate: unknown source type {kind}"
         ))),
     }
 }