Return error if db.JSON decode hook gets an invalid type

Makefile

@@ -6,8 +6,10 @@ lure: version.txt
 clean:
 	rm -f lure
 
-install: lure
+install: lure installmisc
 	install -Dm755 lure $(DESTDIR)$(PREFIX)/bin/lure
+
+installmisc:
 	install -Dm755 scripts/completion/bash $(DESTDIR)$(PREFIX)/share/bash-completion/completions/lure
 	install -Dm755 scripts/completion/zsh $(DESTDIR)$(PREFIX)/share/zsh/site-functions/_lure
 

build.go

@@ -41,6 +41,7 @@ import (
 	"go.arsenm.dev/logger/log"
 	"go.arsenm.dev/lure/distro"
 	"go.arsenm.dev/lure/download"
+	"go.arsenm.dev/lure/internal/cliutils"
 	"go.arsenm.dev/lure/internal/config"
 	"go.arsenm.dev/lure/internal/cpu"
 	"go.arsenm.dev/lure/internal/repos"
@@ -186,13 +187,13 @@ func buildPackage(ctx context.Context, script string, mgr manager.Manager) ([]st
 		return nil, nil, err
 	}
 
-	err = promptViewScript(script, vars.Name)
+	err = cliutils.PromptViewScript(script, vars.Name, cfg.PagerStyle)
 	if err != nil {
 		log.Fatal("Failed to prompt user to view build script").Err(err).Send()
 	}
 
 	if !archMatches(vars.Architectures) {
-		buildAnyway, err := yesNoPrompt("Your system's CPU architecture doesn't match this package. Do you want to build anyway?", true)
+		buildAnyway, err := cliutils.YesNoPrompt("Your system's CPU architecture doesn't match this package. Do you want to build anyway?", true)
 		if err != nil {
 			return nil, nil, err
 		}
@@ -267,7 +268,7 @@ func buildPackage(ctx context.Context, script string, mgr manager.Manager) ([]st
 		}
 
 		log.Info("Installing build dependencies").Send()
-		installPkgs(ctx, flattenFoundPkgs(found, "install"), notFound, mgr)
+		installPkgs(ctx, cliutils.FlattenPkgs(found, "install"), notFound, mgr)
 	}
 
 	var builtDeps, builtNames, repoDeps []string
@@ -279,7 +280,7 @@ func buildPackage(ctx context.Context, script string, mgr manager.Manager) ([]st
 			return nil, nil, err
 		}
 
-		scripts := getScriptPaths(flattenFoundPkgs(found, "install"))
+		scripts := getScriptPaths(cliutils.FlattenPkgs(found, "install"))
 		for _, script := range scripts {
 			pkgPaths, pkgNames, err := buildPackage(ctx, script, mgr)
 			if err != nil {
@@ -490,7 +491,7 @@ func buildPackage(ctx context.Context, script string, mgr manager.Manager) ([]st
 	}
 
 	if len(buildDeps) > 0 {
-		removeBuildDeps, err := yesNoPrompt("Would you like to remove build dependencies?", false)
+		removeBuildDeps, err := cliutils.YesNoPrompt("Would you like to remove build dependencies?", false)
 		if err != nil {
 			return nil, nil, err
 		}

cli.go

@@ -1,91 +0,0 @@
-package main
-
-import (
-	"os"
-
-	"github.com/AlecAivazis/survey/v2"
-	"go.arsenm.dev/logger/log"
-	"go.arsenm.dev/lure/internal/db"
-	"go.arsenm.dev/lure/internal/pager"
-)
-
-// pkgPrompt asks the user to choose between multiple packages.
-// The user may choose multiple packages.
-func pkgPrompt(options []db.Package, verb string) ([]db.Package, error) {
-	names := make([]string, len(options))
-	for i, option := range options {
-		names[i] = option.Repository + "/" + option.Name + " " + option.Version
-	}
-
-	prompt := &survey.MultiSelect{
-		Options: names,
-		Message: "Choose which package(s) to " + verb,
-	}
-
-	var choices []int
-	err := survey.AskOne(prompt, &choices)
-	if err != nil {
-		return nil, err
-	}
-
-	out := make([]db.Package, len(choices))
-	for i, choiceIndex := range choices {
-		out[i] = options[choiceIndex]
-	}
-
-	return out, nil
-}
-
-// yesNoPrompt asks the user a yes or no question, using def as the default answer
-func yesNoPrompt(msg string, def bool) (bool, error) {
-	var answer bool
-	err := survey.AskOne(
-		&survey.Confirm{
-			Message: msg,
-			Default: def,
-		},
-		&answer,
-	)
-	return answer, err
-}
-
-func promptViewScript(script string, name string) error {
-	view, err := yesNoPrompt("Would you like to view the build script for "+name, false)
-	if err != nil {
-		return err
-	}
-
-	if view {
-		err = showScript(script, name)
-		if err != nil {
-			return err
-		}
-
-		cont, err := yesNoPrompt("Would you still like to continue?", false)
-		if err != nil {
-			return err
-		}
-
-		if !cont {
-			log.Fatal("User chose not to continue after reading script").Send()
-		}
-	}
-
-	return nil
-}
-
-func showScript(path, name string) error {
-	scriptFl, err := os.Open(path)
-	if err != nil {
-		return err
-	}
-	defer scriptFl.Close()
-
-	str, err := pager.SyntaxHighlightBash(scriptFl, cfg.PagerStyle)
-	if err != nil {
-		return err
-	}
-
-	pgr := pager.New(name, str)
-	return pgr.Run()
-}

info.go

@@ -26,6 +26,7 @@ import (
 
 	"github.com/urfave/cli/v2"
 	"go.arsenm.dev/lure/distro"
+	"go.arsenm.dev/lure/internal/cliutils"
 	"go.arsenm.dev/lure/internal/overrides"
 	"go.arsenm.dev/lure/internal/repos"
 	"gopkg.in/yaml.v3"
@@ -51,7 +52,7 @@ func infoCmd(c *cli.Context) error {
 		os.Exit(1)
 	}
 
-	pkgs := flattenFoundPkgs(found, "show")
+	pkgs := cliutils.FlattenPkgs(found, "show")
 
 	var names []string
 	all := c.Bool("all")

install.go

@@ -25,6 +25,7 @@ import (
 	"go.arsenm.dev/logger/log"
 
 	"github.com/urfave/cli/v2"
+	"go.arsenm.dev/lure/internal/cliutils"
 	"go.arsenm.dev/lure/internal/config"
 	"go.arsenm.dev/lure/internal/db"
 	"go.arsenm.dev/lure/internal/repos"
@@ -52,7 +53,7 @@ func installCmd(c *cli.Context) error {
 		log.Fatal("Error finding packages").Err(err).Send()
 	}
 
-	installPkgs(c.Context, flattenFoundPkgs(found, "install"), notFound, mgr)
+	installPkgs(c.Context, cliutils.FlattenPkgs(found, "install"), notFound, mgr)
 	return nil
 }
 
@@ -80,24 +81,6 @@ func getScriptPaths(pkgs []db.Package) []string {
 	return scripts
 }
 
-// flattenFoundPkgs attempts to flatten the map of slices of packages into a single slice
-// of packages by prompting the users if multiple packages match.
-func flattenFoundPkgs(found map[string][]db.Package, verb string) []db.Package {
-	var outPkgs []db.Package
-	for _, pkgs := range found {
-		if len(pkgs) > 1 {
-			choices, err := pkgPrompt(pkgs, verb)
-			if err != nil {
-				log.Fatal("Error prompting for choice of package").Send()
-			}
-			outPkgs = append(outPkgs, choices...)
-		} else if len(pkgs) == 1 {
-			outPkgs = append(outPkgs, pkgs[0])
-		}
-	}
-	return outPkgs
-}
-
 // installScripts builds and installs LURE build scripts
 func installScripts(ctx context.Context, mgr manager.Manager, scripts []string) {
 	for _, script := range scripts {

internal/cliutils/prompt.go

@@ -0,0 +1,114 @@
+package cliutils
+
+import (
+	"os"
+
+	"github.com/AlecAivazis/survey/v2"
+	"go.arsenm.dev/logger/log"
+	"go.arsenm.dev/lure/internal/db"
+	"go.arsenm.dev/lure/internal/pager"
+)
+
+// YesNoPrompt asks the user a yes or no question, using def as the default answer
+func YesNoPrompt(msg string, def bool) (bool, error) {
+	var answer bool
+	err := survey.AskOne(
+		&survey.Confirm{
+			Message: msg,
+			Default: def,
+		},
+		&answer,
+	)
+	return answer, err
+}
+
+// PromptViewScript asks the user if they'd like to see a script,
+// shows it if they answer yes, then asks if they'd still like to
+// continue, and exits if they answer no.
+func PromptViewScript(script, name, style string) error {
+	view, err := YesNoPrompt("Would you like to view the build script for "+name, false)
+	if err != nil {
+		return err
+	}
+
+	if view {
+		err = ShowScript(script, name, style)
+		if err != nil {
+			return err
+		}
+
+		cont, err := YesNoPrompt("Would you still like to continue?", false)
+		if err != nil {
+			return err
+		}
+
+		if !cont {
+			log.Fatal("User chose not to continue after reading script").Send()
+		}
+	}
+
+	return nil
+}
+
+// ShowScript uses the built-in pager to display a script at a
+// given path, in the given syntax highlighting style.
+func ShowScript(path, name, style string) error {
+	scriptFl, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+	defer scriptFl.Close()
+
+	str, err := pager.SyntaxHighlightBash(scriptFl, style)
+	if err != nil {
+		return err
+	}
+
+	pgr := pager.New(name, str)
+	return pgr.Run()
+}
+
+// FlattenPkgs attempts to flatten the a map of slices of packages into a single slice
+// of packages by prompting the user if multiple packages match.
+func FlattenPkgs(found map[string][]db.Package, verb string) []db.Package {
+	var outPkgs []db.Package
+	for _, pkgs := range found {
+		if len(pkgs) > 1 {
+			choices, err := PkgPrompt(pkgs, verb)
+			if err != nil {
+				log.Fatal("Error prompting for choice of package").Send()
+			}
+			outPkgs = append(outPkgs, choices...)
+		} else if len(pkgs) == 1 {
+			outPkgs = append(outPkgs, pkgs[0])
+		}
+	}
+	return outPkgs
+}
+
+// PkgPrompt asks the user to choose between multiple packages.
+// The user may choose multiple packages.
+func PkgPrompt(options []db.Package, verb string) ([]db.Package, error) {
+	names := make([]string, len(options))
+	for i, option := range options {
+		names[i] = option.Repository + "/" + option.Name + " " + option.Version
+	}
+
+	prompt := &survey.MultiSelect{
+		Options: names,
+		Message: "Choose which package(s) to " + verb,
+	}
+
+	var choices []int
+	err := survey.AskOne(prompt, &choices)
+	if err != nil {
+		return nil, err
+	}
+
+	out := make([]db.Package, len(choices))
+	for i, choiceIndex := range choices {
+		out[i] = options[choiceIndex]
+	}
+
+	return out, nil
+}

internal/shutils/decoder/decoder.go

@@ -33,7 +33,7 @@ import (
 	"mvdan.cc/sh/v3/syntax"
 )
 
-var ErrInvalidType = errors.New("val must be a pointer to a struct")
+var ErrNotPointerToStruct = errors.New("val must be a pointer to a struct")
 
 type VarNotFoundError struct {
 	name string
@@ -43,6 +43,16 @@ func (nfe VarNotFoundError) Error() string {
 	return "required variable '" + nfe.name + "' could not be found"
 }
 
+type InvalidTypeError struct {
+	name    string
+	vartype string
+	exptype string
+}
+
+func (ite InvalidTypeError) Error() string {
+	return "variable '" + ite.name + "' is of type " + ite.vartype + ", but " + ite.exptype + " is expected"
+}
+
 // Decoder provides methods for decoding variable values
 type Decoder struct {
 	info   *distro.OSRelease
@@ -70,6 +80,11 @@ func (d *Decoder) DecodeVar(name string, val any) error {
 		WeaklyTypedInput: true,
 		DecodeHook: mapstructure.DecodeHookFuncValue(func(from, to reflect.Value) (interface{}, error) {
 			if strings.Contains(to.Type().String(), "db.JSON") {
+				valType := to.FieldByName("Val").Type()
+				if !from.Type().AssignableTo(valType) {
+					return nil, InvalidTypeError{name, from.Type().String(), valType.String()}
+				}
+
 				to.FieldByName("Val").Set(from)
 				return to, nil
 			}
@@ -97,11 +112,11 @@ func (d *Decoder) DecodeVar(name string, val any) error {
 func (d *Decoder) DecodeVars(val any) error {
 	valKind := reflect.TypeOf(val).Kind()
 	if valKind != reflect.Pointer {
-		return ErrInvalidType
+		return ErrNotPointerToStruct
 	} else {
 		elemKind := reflect.TypeOf(val).Elem().Kind()
 		if elemKind != reflect.Struct {
-			return ErrInvalidType
+			return ErrNotPointerToStruct
 		}
 	}