always recompute Devbox environment, and reuse buildInputs from print-dev-env output

Author: savil

internal/devbox/nixprofile.go

@@ -2,7 +2,6 @@ package devbox
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
 	"strings"
 
@@ -12,39 +11,31 @@ import (
 
 // syncFlakeToProfile ensures the buildInputs from the flake's devShell are
 // installed in the nix profile.
-func (d *Devbox) syncFlakeToProfile(ctx context.Context) error {
+// buildInputs is a space-separated list of store paths from the nix print-dev-env output's buildInputs.
+func (d *Devbox) syncFlakeToProfile(ctx context.Context, buildInputs string) error {
 	profilePath, err := d.profilePath()
 	if err != nil {
 		return err
 	}
 
-	// Get the build inputs (i.e. store paths) from the generated flake's devShell.
-	buildInputPaths, err := nix.Eval(
-		ctx,
-		d.stderr,
-		d.flakeDir()+"#devShells."+nix.System()+".default.buildInputs",
-		"--json",
-	)
-	if err != nil {
-		return fmt.Errorf("nix eval devShells: %v", err)
-	}
-	storePaths := []string{}
-	if err := json.Unmarshal(buildInputPaths, &storePaths); err != nil {
-		return fmt.Errorf("unmarshal store paths: %s: %v", buildInputPaths, err)
+	// Get the build inputs (i.e. store paths) from the generated flake's print-dev-env output
+	wantStorePaths := []string{}
+	if buildInputs != "" { // if buildInputs is empty, then we don't want wantStorePaths to be an array with a single "" entry
+		wantStorePaths = strings.Split(buildInputs, " ")
 	}
 
 	// Get the store-paths of the packages currently installed in the nix profile
 	items, err := nixprofile.ProfileListItems(ctx, d.stderr, profilePath)
 	if err != nil {
 		return fmt.Errorf("nix profile list: %v", err)
 	}
-	got := make([]string, 0, len(items))
+	gotStorePaths := make([]string, 0, len(items))
 	for _, item := range items {
-		got = append(got, item.StorePaths()...)
+		gotStorePaths = append(gotStorePaths, item.StorePaths()...)
 	}
 
 	// Diff the store paths and install/remove packages as needed
-	add, remove := diffStorePaths(got, storePaths)
+	add, remove := diffStorePaths(gotStorePaths, wantStorePaths)
 	if len(remove) > 0 {
 		packagesToRemove := make([]string, 0, len(remove))
 		for _, p := range remove {

internal/devbox/packages.go

@@ -292,17 +292,15 @@ func (d *Devbox) ensureStateIsUpToDate(ctx context.Context, mode installMode) er
 		return err
 	}
 
-	// Skip the print-dev-env's cache if we are in a devbox-environment. If not,
-	// skip the cache if we're either installing packages or ensuring
-	// the project state is up-to-date.
-	skipPrintDevEnvCache := true
-	// skipPrintDevEnvCache := d.IsEnvEnabled() || (mode == ensure || mode == install)
-	if _, err := d.computeEnv(ctx, !skipPrintDevEnvCache /*usePrintDevEnvCache*/); err != nil {
+	// Always re-compute print-dev-env to ensure all packages are installed, and
+	// the correct set of packages are reflected in the nix-profile below.
+	env, err := d.computeEnv(ctx, false /*usePrintDevEnvCache*/)
+	if err != nil {
 		return err
 	}
 
 	// Ensure the nix profile has the packages from the flake.
-	if err := d.syncFlakeToProfile(ctx); err != nil {
+	if err := d.syncFlakeToProfile(ctx, env["buildInputs"]); err != nil {
 		return err
 	}
 

internal/devpkg/validation.go

@@ -38,7 +38,7 @@ func (p *Package) ValidateInstallsOnSystem() (bool, error) {
 	if len(info) == 0 {
 		return false, nil
 	}
-	if out, err := nix.RawEval(u); err != nil &&
+	if out, err := nix.Eval(u); err != nil &&
 		strings.Contains(string(out), "is not available on the requested hostPlatform") {
 		return false, nil
 	}

internal/nix/eval.go

@@ -1,9 +1,7 @@
 package nix
 
 import (
-	"context"
 	"encoding/json"
-	"io"
 	"os"
 	"strconv"
 )
@@ -48,22 +46,14 @@ func PackageKnownVulnerabilities(path string) []string {
 	return vulnerabilities
 }
 
-// RawEval is nix eval. Needs to be parsed. Useful for stuff like
+// Eval is raw nix eval. Needs to be parsed. Useful for stuff like
 // nix eval --raw nixpkgs/9ef09e06806e79e32e30d17aee6879d69c011037#fuse3
 // to determine if a package if a package can be installed in system.
-func RawEval(path string) ([]byte, error) {
+func Eval(path string) ([]byte, error) {
 	cmd := command("eval", "--raw", path)
 	return cmd.CombinedOutput()
 }
 
-func Eval(ctx context.Context, w io.Writer, installable string, options ...string) ([]byte, error) {
-	args := []string{"eval", installable}
-	args = append(args, options...)
-	cmd := commandContext(ctx, args...)
-	cmd.Stderr = w
-	return cmd.Output()
-}
-
 func AllowInsecurePackages() {
 	os.Setenv("NIXPKGS_ALLOW_INSECURE", "1")
 }