Define immutable configuration searches

This commit is contained in:
2026-10-24 15:39:59 +00:00
parent 424c89780e
commit e2634c8815
4 changed files with 488 additions and 2 deletions

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@@ -0,0 +1,266 @@
package engine
import (
"path/filepath"
"runtime"
"strings"
)
// Search is an immutable ordered description of possible host-file inputs.
// It does not access the filesystem until a later loading integration consumes it.
type Search struct {
entries []searchEntry
issues []string
}
// FilenameGroup is an immutable ordered group used by a directory search.
type FilenameGroup struct {
kind filenameGroupKind
names []string
issues []string
}
// DirectorySearchOptions controls the filename groups used by SearchDirectory.
// A nil Filenames slice selects the default groups; a non-nil empty slice selects none.
type DirectorySearchOptions struct {
Filenames []FilenameGroup
}
// SearchOptions controls whether a later source consumption requires a match.
type SearchOptions struct {
Required bool
}
type filenameGroupKind uint8
const (
filenameGroupEmpty filenameGroupKind = iota
filenameGroupNamed
filenameGroupGeneric
filenameGroupCustom
)
type searchEntryKind uint8
const (
searchEntryPath searchEntryKind = iota + 1
searchEntryDirectory
)
type directoryBaseKind uint8
const (
directoryBaseLiteral directoryBaseKind = iota
directoryBaseUnixLocal
directoryBaseUnixEtc
directoryBaseUserConfig
directoryBaseHome
directoryBaseWorking
)
type searchEntry struct {
kind searchEntryKind
path string
baseKind directoryBaseKind
directory string
appendSlug bool
slugPrefix string
filenames []FilenameGroup
}
// NamedFilenames selects <application>.yml followed by <application>.yaml.
func NamedFilenames() FilenameGroup {
return FilenameGroup{kind: filenameGroupNamed}
}
// GenericFilenames selects config.yml, config.yaml, main.yml, and main.yaml.
func GenericFilenames() FilenameGroup {
return FilenameGroup{kind: filenameGroupGeneric}
}
// CustomFilenames selects literal filename components in the supplied order.
func CustomFilenames(names ...string) FilenameGroup {
group := FilenameGroup{kind: filenameGroupCustom, names: append([]string(nil), names...)}
for _, name := range group.names {
if !validFilenameComponent(name) {
group.issues = append(group.issues, "custom filename must be a usable host filename component")
}
}
return group
}
// SearchDirectory searches the supplied directory using the selected filename groups.
// With omitted options or nil Filenames, it selects Named then Generic filenames.
func SearchDirectory(directory string, supplied ...DirectorySearchOptions) Search {
search := Search{}
if len(supplied) > 1 {
search.issues = append(search.issues, "directory search accepts at most one options value")
}
var groups []FilenameGroup
if len(supplied) == 0 || supplied[0].Filenames == nil {
groups = []FilenameGroup{NamedFilenames(), GenericFilenames()}
} else {
groups = cloneFilenameGroups(supplied[0].Filenames)
}
search.entries = append(search.entries, searchEntry{
kind: searchEntryDirectory, baseKind: directoryBaseLiteral,
directory: directory, filenames: groups,
})
return search
}
// Paths describes literal host-file candidates in the supplied order.
func Paths(paths ...string) Search {
search := Search{entries: make([]searchEntry, 0, len(paths))}
for _, path := range append([]string(nil), paths...) {
search.entries = append(search.entries, searchEntry{kind: searchEntryPath, path: path})
}
return search
}
// Searches concatenates descriptions in order and snapshots their entries.
func Searches(searches ...Search) Search {
result := Search{}
for _, search := range append([]Search(nil), searches...) {
result.entries = append(result.entries, cloneSearchEntries(search.entries)...)
result.issues = append(result.issues, search.issues...)
}
return result
}
// UnixSystemDirectories describes the conventional Unix system directories.
func UnixSystemDirectories() Search {
namedGeneric := []FilenameGroup{NamedFilenames(), GenericFilenames()}
return Search{entries: []searchEntry{
{kind: searchEntryDirectory, baseKind: directoryBaseUnixLocal, appendSlug: true, filenames: cloneFilenameGroups(namedGeneric)},
{kind: searchEntryDirectory, baseKind: directoryBaseUnixEtc, appendSlug: true, filenames: cloneFilenameGroups(namedGeneric)},
{kind: searchEntryDirectory, baseKind: directoryBaseUnixEtc, filenames: []FilenameGroup{NamedFilenames()}},
}}
}
// UserConfigDirectory describes the Go user-configuration directory searches.
func UserConfigDirectory() Search {
return Search{entries: []searchEntry{
{kind: searchEntryDirectory, baseKind: directoryBaseUserConfig, appendSlug: true, filenames: defaultFilenameGroups()},
{kind: searchEntryDirectory, baseKind: directoryBaseUserConfig, filenames: []FilenameGroup{NamedFilenames()}},
}}
}
// HomeDirectory describes the Go home-directory searches.
func HomeDirectory() Search {
return Search{entries: []searchEntry{
{kind: searchEntryDirectory, baseKind: directoryBaseHome, appendSlug: true, slugPrefix: ".", filenames: defaultFilenameGroups()},
{kind: searchEntryDirectory, baseKind: directoryBaseHome, filenames: []FilenameGroup{NamedFilenames()}},
}}
}
// WorkingDirectory describes application-named files in the current directory.
func WorkingDirectory() Search {
return Search{entries: []searchEntry{{
kind: searchEntryDirectory, baseKind: directoryBaseWorking,
filenames: []FilenameGroup{NamedFilenames()},
}}}
}
func defaultFilenameGroups() []FilenameGroup {
return []FilenameGroup{NamedFilenames(), GenericFilenames()}
}
func cloneFilenameGroups(groups []FilenameGroup) []FilenameGroup {
if groups == nil {
return nil
}
cloned := make([]FilenameGroup, len(groups))
for i, group := range groups {
cloned[i] = FilenameGroup{
kind: group.kind, names: append([]string(nil), group.names...),
issues: append([]string(nil), group.issues...),
}
}
return cloned
}
func cloneSearchEntries(entries []searchEntry) []searchEntry {
if entries == nil {
return nil
}
cloned := make([]searchEntry, len(entries))
for i, entry := range entries {
cloned[i] = entry
cloned[i].filenames = cloneFilenameGroups(entry.filenames)
}
return cloned
}
func validateSearch(search Search, application string) []Diagnostic {
var diagnostics []Diagnostic
for _, issue := range search.issues {
diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, issue))
}
slugNeeded := false
for _, entry := range search.entries {
switch entry.kind {
case searchEntryPath:
if entry.path == "" {
diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, "search path must not be empty"))
}
case searchEntryDirectory:
if entry.baseKind == directoryBaseLiteral && entry.directory == "" {
diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, "directory search path must not be empty"))
}
if entry.appendSlug {
slugNeeded = true
}
for _, group := range entry.filenames {
switch group.kind {
case filenameGroupEmpty, filenameGroupGeneric:
case filenameGroupNamed:
slugNeeded = true
case filenameGroupCustom:
default:
diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, "filename group is invalid"))
}
for _, issue := range group.issues {
diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, issue))
}
}
default:
diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, "search description is invalid"))
}
}
if slugNeeded && !validFilenameComponent(application) {
diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, "application name must be a usable host filename component"))
}
return canonicalDiagnostics(diagnostics)
}
func validFilenameComponent(value string) bool {
if value == "" || value == "." || value == ".." || strings.IndexByte(value, 0) >= 0 {
return false
}
if filepath.IsAbs(value) || filepath.VolumeName(value) != "" || filepath.Base(value) != value {
return false
}
if runtime.GOOS == "windows" {
return validWindowsFilenameComponent(value)
}
return true
}
func validWindowsFilenameComponent(value string) bool {
if strings.ContainsAny(value, `<>:"|?*`) || strings.HasSuffix(value, ".") || strings.HasSuffix(value, " ") {
return false
}
for _, character := range value {
if character < 32 {
return false
}
}
base := strings.ToUpper(strings.TrimSuffix(value, filepath.Ext(value)))
switch base {
case "CON", "PRN", "AUX", "NUL", "COM1", "COM2", "COM3", "COM4", "COM5", "COM6", "COM7", "COM8", "COM9", "COM¹", "COM²", "COM³", "LPT1", "LPT2", "LPT3", "LPT4", "LPT5", "LPT6", "LPT7", "LPT8", "LPT9", "LPT¹", "LPT²", "LPT³":
return false
default:
return true
}
}

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package engine
import (
"runtime"
"testing"
)
func TestSearchDescriptionEmptyAndSlugRequirements(t *testing.T) {
t.Parallel()
if diagnostics := validateSearch(Search{}, ""); len(diagnostics) != 0 {
t.Fatalf("zero search diagnostics = %#v", diagnostics)
}
if diagnostics := validateSearch(Searches(), ""); len(diagnostics) != 0 {
t.Fatalf("empty concatenation diagnostics = %#v", diagnostics)
}
if diagnostics := validateSearch(Paths(), ""); len(diagnostics) != 0 {
t.Fatalf("empty path list diagnostics = %#v", diagnostics)
}
if diagnostics := validateSearch(Paths("relative/config.yml"), ""); len(diagnostics) != 0 {
t.Fatalf("literal path unexpectedly requires a slug: %#v", diagnostics)
}
generic := SearchDirectory("configs", DirectorySearchOptions{Filenames: []FilenameGroup{GenericFilenames()}})
if diagnostics := validateSearch(generic, ""); len(diagnostics) != 0 {
t.Fatalf("generic-only directory unexpectedly requires a slug: %#v", diagnostics)
}
if diagnostics := validateSearch(SearchDirectory("configs"), ""); len(diagnostics) == 0 || diagnostics[0].Code != CodeOptionsInvalid {
t.Fatalf("default named directory accepted an empty slug: %#v", diagnostics)
}
if diagnostics := validateSearch(UnixSystemDirectories(), "myapp"); len(diagnostics) != 0 {
t.Fatalf("valid preset slug diagnostics = %#v", diagnostics)
}
}
func TestSearchDescriptionSnapshotsInputs(t *testing.T) {
t.Parallel()
paths := []string{"first.yml", "second.yml"}
pathSearch := Paths(paths...)
paths[0] = "changed.yml"
customNames := []string{"one.yml", "two.yml"}
group := CustomFilenames(customNames...)
customNames[0] = "changed.yml"
groups := []FilenameGroup{group}
options := DirectorySearchOptions{Filenames: groups}
directorySearch := SearchDirectory("configs", options)
groups[0] = GenericFilenames()
options.Filenames[0] = NamedFilenames()
searches := []Search{pathSearch, directorySearch}
combined := Searches(searches...)
searches[0] = Search{}
if got := combined.entries[0].path; got != "first.yml" {
t.Fatalf("snapshotted path = %q", got)
}
gotNames := combined.entries[2].filenames[0].names
if len(gotNames) != 2 || gotNames[0] != "one.yml" || gotNames[1] != "two.yml" {
t.Fatalf("snapshotted custom names = %#v", gotNames)
}
if diagnostics := validateSearch(combined, ""); len(diagnostics) != 0 {
t.Fatalf("snapshot description diagnostics = %#v", diagnostics)
}
}
func TestDirectoryFilenameDefaultsAndExplicitEmpty(t *testing.T) {
t.Parallel()
omitted := SearchDirectory("configs")
if len(omitted.entries) != 1 || len(omitted.entries[0].filenames) != 2 || omitted.entries[0].filenames[0].kind != filenameGroupNamed || omitted.entries[0].filenames[1].kind != filenameGroupGeneric {
t.Fatalf("omitted groups = %#v", omitted.entries)
}
explicitNil := SearchDirectory("configs", DirectorySearchOptions{})
if len(explicitNil.entries[0].filenames) != 2 {
t.Fatalf("nil filename selection did not use defaults: %#v", explicitNil.entries[0].filenames)
}
explicitEmpty := SearchDirectory("configs", DirectorySearchOptions{Filenames: []FilenameGroup{}})
if explicitEmpty.entries[0].filenames == nil || len(explicitEmpty.entries[0].filenames) != 0 {
t.Fatalf("explicit empty selection lost its distinction: %#v", explicitEmpty.entries[0].filenames)
}
if len(validateSearch(explicitEmpty, "")) != 0 {
t.Fatal("explicit empty filename selection should need no slug")
}
}
func TestSearchDescriptionArityAndErrorConcatenation(t *testing.T) {
t.Parallel()
tooMany := SearchDirectory("configs", DirectorySearchOptions{}, DirectorySearchOptions{})
if diagnostics := validateSearch(tooMany, "app"); len(diagnostics) == 0 {
t.Fatal("multiple option values should be invalid")
}
invalid := Paths("")
combined := Searches(Paths("good.yml"), invalid)
if diagnostics := validateSearch(combined, ""); len(diagnostics) == 0 {
t.Fatal("concatenation lost a constructor error")
}
if diagnostics := validateSearch(Paths("good.yml", ""), ""); len(diagnostics) == 0 {
t.Fatal("later invalid path was hidden by an earlier component")
}
}
func TestSearchDescriptionPreservesFilenameGroupOrder(t *testing.T) {
t.Parallel()
groups := []FilenameGroup{GenericFilenames(), NamedFilenames(), CustomFilenames("override.yml")}
search := SearchDirectory("configs", DirectorySearchOptions{Filenames: groups})
got := search.entries[0].filenames
if len(got) != 3 || got[0].kind != filenameGroupGeneric || got[1].kind != filenameGroupNamed || got[2].names[0] != "override.yml" {
t.Fatalf("filename group order = %#v", got)
}
if got := SearchDirectory("configs", DirectorySearchOptions{Filenames: []FilenameGroup{CustomFilenames()}}).entries[0].filenames[0].names; len(got) != 0 {
t.Fatalf("empty custom group = %#v", got)
}
}
func TestFilenameComponentValidation(t *testing.T) {
t.Parallel()
for _, value := range []string{"", ".", "..", "nested/name", "bad\x00name"} {
if validFilenameComponent(value) {
t.Errorf("validFilenameComponent(%q) = true", value)
}
}
if runtime.GOOS == "windows" {
for _, value := range []string{"CON", "nul.txt", "name.", "bad:name"} {
if validFilenameComponent(value) {
t.Errorf("Windows component %q unexpectedly accepted", value)
}
}
} else {
for _, value := range []string{"name with spaces", "naïve"} {
if !validFilenameComponent(value) {
t.Errorf("host-valid component %q rejected", value)
}
}
}
if diagnostics := validateSearch(SearchDirectory("configs", DirectorySearchOptions{Filenames: []FilenameGroup{CustomFilenames("bad/name")}}), ""); len(diagnostics) == 0 {
t.Fatal("invalid custom filename was not retained for validation")
}
for _, value := range []string{"CON", "nul.txt", "COM¹.log", "LPT³.txt", "name.", "bad:name", "bad\x01name"} {
if validWindowsFilenameComponent(value) {
t.Errorf("Windows component %q unexpectedly accepted", value)
}
}
for _, value := range []string{"name with spaces", "naïve"} {
if !validWindowsFilenameComponent(value) {
t.Errorf("valid Windows component %q rejected", value)
}
}
}