feat: treat tag setting keys as anchored regex patterns (#5759)

Co-authored-by: memoclaw <265580040+memoclaw@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

proto/api/v1/instance_service.proto

@@ -173,6 +173,10 @@ message InstanceSetting {
 
   // Tag metadata configuration.
   message TagsSetting {
+    // Map of tag name pattern to tag metadata.
+    // Each key is treated as an anchored regular expression (^pattern$),
+    // so a single entry like "project/.*" matches all tags under that prefix.
+    // Exact tag names are also valid (they are trivially valid regex patterns).
     map<string, TagMetadata> tags = 1;
   }
 

proto/store/instance_setting.proto

@@ -116,6 +116,10 @@ message InstanceTagMetadata {
 }
 
 message InstanceTagsSetting {
+  // Map of tag name pattern to tag metadata.
+  // Each key is treated as an anchored regular expression (^pattern$),
+  // so a single entry like "project/.*" matches all tags under that prefix.
+  // Exact tag names are also valid (they are trivially valid regex patterns).
   map<string, InstanceTagMetadata> tags = 1;
 }
 

server/router/api/v1/instance_service.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"math"
+	"regexp"
 	"strings"
 
 	"github.com/pkg/errors"
@@ -391,6 +392,9 @@ func validateInstanceTagsSetting(setting *v1pb.InstanceSetting_TagsSetting) erro
 		if strings.TrimSpace(tag) == "" {
 			return errors.New("tag key cannot be empty")
 		}
+		if _, err := regexp.Compile(tag); err != nil {
+			return errors.Errorf("tag key %q is not a valid regex pattern: %v", tag, err)
+		}
 		if metadata == nil {
 			return errors.Errorf("tag metadata is required for %q", tag)
 		}

web/src/components/MemoContent/Tag.tsx

@@ -4,6 +4,7 @@ import { useInstance } from "@/contexts/InstanceContext";
 import { type MemoFilter, stringifyFilters, useMemoFilterContext } from "@/contexts/MemoFilterContext";
 import useNavigateTo from "@/hooks/useNavigateTo";
 import { colorToHex } from "@/lib/color";
+import { findTagMetadata } from "@/lib/tag";
 import { cn } from "@/lib/utils";
 import { Routes } from "@/router";
 import { useMemoViewContext } from "../MemoView/MemoViewContext";
@@ -26,7 +27,7 @@ export const Tag: React.FC<TagProps> = ({ "data-tag": dataTag, children, classNa
   // Custom color from admin tag metadata. Dynamic hex values must use inline styles
   // because Tailwind can't scan dynamically constructed class names.
   // Text uses a darkened variant (40% color + black) for contrast on light backgrounds.
-  const bgHex = colorToHex(tagsSetting.tags[tag]?.backgroundColor);
+  const bgHex = colorToHex(findTagMetadata(tag, tagsSetting)?.backgroundColor);
   const tagStyle: React.CSSProperties | undefined = bgHex
     ? {
         borderColor: bgHex,
@@ -65,7 +66,7 @@ export const Tag: React.FC<TagProps> = ({ "data-tag": dataTag, children, classNa
   return (
     <span
       className={cn(
-        "inline-flex items-center align-middle px-1.5 py-px text-sm leading-snug rounded border cursor-pointer transition-opacity hover:opacity-75",
+        "inline-flex items-center px-1 text-sm rounded-full border cursor-pointer transition-opacity hover:opacity-75",
         !bgHex && "border-primary text-primary bg-primary/15",
         className,
       )}

web/src/components/Settings/TagsSection.tsx

@@ -9,6 +9,7 @@ import { useInstance } from "@/contexts/InstanceContext";
 import { useTagCounts } from "@/hooks/useUserQueries";
 import { colorToHex } from "@/lib/color";
 import { handleError } from "@/lib/error";
+import { isValidTagPattern } from "@/lib/tag";
 import {
   InstanceSetting_Key,
   InstanceSetting_TagMetadataSchema,
@@ -92,6 +93,10 @@ const TagsSection = () => {
       toast.error(t("setting.tags.tag-already-exists"));
       return;
     }
+    if (!isValidTagPattern(name)) {
+      toast.error(t("setting.tags.invalid-regex"));
+      return;
+    }
     setLocalTags((prev) => ({ ...prev, [name]: newTagColor }));
     setNewTagName("");
     setNewTagColor("#ffffff");
@@ -136,7 +141,6 @@ const TagsSection = () => {
               header: t("setting.tags.background-color"),
               render: (_, row: { name: string }) => (
                 <div className="flex items-center gap-2">
-                  <div className="w-5 h-5 rounded border border-border shrink-0" style={{ backgroundColor: localTags[row.name] }} />
                   <input
                     type="color"
                     className="w-8 h-8 cursor-pointer rounded border border-border bg-transparent p-0.5"
@@ -184,11 +188,12 @@ const TagsSection = () => {
             value={newTagColor}
             onChange={(e) => setNewTagColor(e.target.value)}
           />
-          <Button variant="outline" size="sm" onClick={handleAddTag} disabled={!newTagName.trim()}>
+          <Button variant="outline" onClick={handleAddTag} disabled={!newTagName.trim()}>
             <PlusIcon className="w-4 h-4 mr-1.5" />
             {t("common.add")}
           </Button>
         </div>
+        <p className="text-xs text-muted-foreground mt-1">{t("setting.tags.tag-pattern-hint")}</p>
       </SettingGroup>
 
       <div className="w-full flex justify-end">

web/src/lib/tag.ts

@@ -0,0 +1,64 @@
+import type { InstanceSetting_TagMetadata, InstanceSetting_TagsSetting } from "@/types/proto/api/v1/instance_service_pb";
+
+// Cache compiled regexes to avoid re-compiling on every tag render.
+const compiledPatternCache = new Map<string, RegExp | null>();
+
+const getCompiledPattern = (pattern: string): RegExp | null => {
+  if (compiledPatternCache.has(pattern)) {
+    return compiledPatternCache.get(pattern)!;
+  }
+  let re: RegExp | null = null;
+  try {
+    re = new RegExp(`^(?:${pattern})$`);
+  } catch {
+    // Invalid pattern — cache as null so we skip it without retrying.
+  }
+  compiledPatternCache.set(pattern, re);
+  return re;
+};
+
+/**
+ * Finds the first matching TagMetadata for a given tag name by treating each
+ * key in tagsSetting.tags as an anchored regex pattern (^pattern$).
+ *
+ * Lookup order:
+ * 1. Exact key match (O(1) fast path, backward-compatible).
+ * 2. Iterate all keys and test as anchored regex — first match wins.
+ */
+export const findTagMetadata = (tag: string, tagsSetting: InstanceSetting_TagsSetting): InstanceSetting_TagMetadata | undefined => {
+  // Fast path: exact match.
+  if (tagsSetting.tags[tag]) {
+    return tagsSetting.tags[tag];
+  }
+
+  // Regex path: treat each key as an anchored pattern.
+  for (const [pattern, metadata] of Object.entries(tagsSetting.tags)) {
+    const re = getCompiledPattern(pattern);
+    if (re?.test(tag)) {
+      return metadata;
+    }
+  }
+
+  return undefined;
+};
+
+/**
+ * Returns true if the given string is a valid, ReDoS-safe JavaScript regex pattern.
+ *
+ * Rejects patterns with nested quantifiers (e.g. `(a+)+`) which can cause
+ * catastrophic backtracking in JavaScript's regex engine.
+ */
+export const isValidTagPattern = (pattern: string): boolean => {
+  if (!pattern) return false;
+  try {
+    new RegExp(pattern);
+  } catch {
+    return false;
+  }
+  // Reject nested quantifiers: a quantified group whose body itself contains
+  // a quantifier — the classic ReDoS shape e.g. (a+)+, (a*b?)+, (x|y+)+.
+  if (/\((?:[^()]*[*+?{][^()]*)\)[*+?{]/.test(pattern)) {
+    return false;
+  }
+  return true;
+};

web/src/locales/en.json

@@ -474,12 +474,14 @@
     "tags": {
       "label": "Tags",
       "title": "Tag metadata",
-      "description": "Assign display colors to tags instance-wide.",
+      "description": "Assign display colors to tags instance-wide. Tag names are treated as anchored regex patterns.",
       "background-color": "Background color",
       "no-tags-configured": "No tag metadata configured.",
       "tag-name": "Tag name",
-      "tag-name-placeholder": "e.g. work",
+      "tag-name-placeholder": "e.g. work or project/.*",
-      "tag-already-exists": "Tag already exists."
+      "tag-already-exists": "Tag already exists.",
+      "tag-pattern-hint": "Tag name or regex pattern (e.g. project/.* matches all project/ tags)",
+      "invalid-regex": "Invalid or unsafe regex pattern."
     }
   },
   "tag": {

web/src/pages/Setting.tsx

@@ -34,7 +34,7 @@ import { useTranslate } from "@/utils/i18n";
 type SettingSection = "my-account" | "preference" | "webhook" | "member" | "system" | "memo" | "storage" | "sso" | "tags";
 
 const BASIC_SECTIONS: SettingSection[] = ["my-account", "preference", "webhook"];
-const ADMIN_SECTIONS: SettingSection[] = ["member", "system", "memo", "storage", "tags", "sso"];
+const ADMIN_SECTIONS: SettingSection[] = ["member", "system", "memo", "tags", "storage", "sso"];
 
 const SECTION_ICON_MAP: Record<SettingSection, LucideIcon> = {
   "my-account": UserIcon,