From 4a37d8cbab43715d25816bc08b9c3a3b35d0f5e2 Mon Sep 17 00:00:00 2001
From: Dmitry Patsura <talk@dmtry.me>
Date: Mon, 1 Dec 2025 11:55:38 +0100
Subject: [PATCH 1/7] feat: Support defining custom date formatting for time
 dimensions

---
 .../src/compiler/CubeToMetaTransformer.ts     |  25 +++-
 .../src/compiler/CubeValidator.ts             |  62 +++++++-
 .../test/unit/cube-validator.test.ts          | 135 ++++++++++++++++++
 3 files changed, 219 insertions(+), 3 deletions(-)

diff --git a/packages/cubejs-schema-compiler/src/compiler/CubeToMetaTransformer.ts b/packages/cubejs-schema-compiler/src/compiler/CubeToMetaTransformer.ts
index eb9c786757f12..710e11c88e64f 100644
--- a/packages/cubejs-schema-compiler/src/compiler/CubeToMetaTransformer.ts
+++ b/packages/cubejs-schema-compiler/src/compiler/CubeToMetaTransformer.ts
@@ -77,6 +77,8 @@ export type MeasureConfig = {
   public: boolean;
 };
 
+export type DimensionFormat = string | { type: string; label?: string; value?: string };
+
 export type DimensionConfig = {
   name: string;
   title: string;
@@ -84,7 +86,7 @@ export type DimensionConfig = {
   description?: string;
   shortTitle: string;
   suggestFilterValues: boolean;
-  format?: string;
+  format?: DimensionFormat;
   meta?: any;
   isVisible: boolean;
   public: boolean;
@@ -252,7 +254,7 @@ export class CubeToMetaTransformer implements CompilerInterface {
               extendedDimDef.suggestFilterValues == null
                 ? true
                 : extendedDimDef.suggestFilterValues,
-            format: extendedDimDef.format,
+            format: this.transformDimensionFormat(extendedDimDef),
             meta: extendedDimDef.meta,
             isVisible: dimensionVisibility,
             public: dimensionVisibility,
@@ -390,4 +392,23 @@ export class CubeToMetaTransformer implements CompilerInterface {
   private titleize(name: string): string {
     return inflection.titleize(inflection.underscore(camelCase(name, { pascalCase: true })));
   }
+
+  private transformDimensionFormat({ format, type }: ExtendedCubeSymbolDefinition): DimensionFormat | undefined {
+    if (!format || type !== 'time') {
+      return format;
+    }
+
+    if (typeof format === 'object') {
+      return format;
+    }
+
+    // I don't know why, but we allow to define these formats for time dimensions.
+    // TODO: Should we deprecate it?
+    const standardFormats = ['imageUrl', 'currency', 'percent', 'number', 'id'];
+    if (standardFormats.includes(format)) {
+      return format;
+    }
+
+    return { type: 'custom-date', value: format };
+  }
 }
diff --git a/packages/cubejs-schema-compiler/src/compiler/CubeValidator.ts b/packages/cubejs-schema-compiler/src/compiler/CubeValidator.ts
index 9df65fd95fc98..078eada13a966 100644
--- a/packages/cubejs-schema-compiler/src/compiler/CubeValidator.ts
+++ b/packages/cubejs-schema-compiler/src/compiler/CubeValidator.ts
@@ -119,6 +119,62 @@ const formatSchema = Joi.alternatives([
   })
 ]);
 
+const DATE_FORMAT_SPECIFIERS = new Set(['d', 'm', 'y', 'h', 'n', 's', 'q', 'w']);
+const DATE_FORMAT_SEPARATORS = new Set(['-', '/', ':', '.', ',', ' ']);
+
+const customDateFormatSchema = Joi.string().custom((value, helper) => {
+  const invalidChars: string[] = [];
+  let hasSpecifier = false;
+
+  let i = 0;
+
+  while (i < value.length) {
+    const char = value[i];
+
+    // Handle quoted literals (skip content inside quotes or brackets)
+    if (char === '"' || char === '\'') {
+      const closeIndex = value.indexOf(char, i + 1);
+      if (closeIndex === -1) {
+        return helper.message({ custom: `Invalid date format "${value}". Unclosed quote at position ${i}` });
+      }
+
+      i = closeIndex + 1;
+    } else if (char === '[') {
+      const closeIndex = value.indexOf(']', i + 1);
+      if (closeIndex === -1) {
+        return helper.message({ custom: `Invalid date format "${value}". Unclosed bracket at position ${i}` });
+      }
+
+      i = closeIndex + 1;
+    } else if (DATE_FORMAT_SPECIFIERS.has(char.toLowerCase())) {
+      hasSpecifier = true;
+      i++;
+    } else if (DATE_FORMAT_SEPARATORS.has(char)) {
+      i++;
+    } else if (char.toUpperCase() === 'A' || char.toUpperCase() === 'P') {
+      i++;
+    } else {
+      invalidChars.push(char);
+      i++;
+    }
+  }
+
+  if (!hasSpecifier) {
+    return helper.message({ custom: `Invalid date format "${value}". Format must contain at least one date/time specifier (d, m, y, h, n, s, q, w)` });
+  }
+
+  if (invalidChars.length > 0) {
+    return helper.message({ custom: `Invalid date format "${value}". Contains invalid characters: "${invalidChars.join('')}". Use quotes for literal text.` });
+  }
+
+  return value;
+});
+
+const timeFormatSchema = Joi.alternatives([
+  formatSchema,
+  customDateFormatSchema
+]);
+
 const BaseDimensionWithoutSubQuery = {
   aliases: Joi.array().items(Joi.string()),
   type: Joi.any().valid('string', 'number', 'boolean', 'time', 'geo').required(),
@@ -131,7 +187,11 @@ const BaseDimensionWithoutSubQuery = {
   description: Joi.string(),
   suggestFilterValues: Joi.boolean().strict(),
   enableSuggestions: Joi.boolean().strict(),
-  format: formatSchema,
+  format: Joi.when('type', {
+    is: 'time',
+    then: timeFormatSchema,
+    otherwise: formatSchema
+  }),
   meta: Joi.any(),
   values: Joi.when('type', {
     is: 'switch',
diff --git a/packages/cubejs-schema-compiler/test/unit/cube-validator.test.ts b/packages/cubejs-schema-compiler/test/unit/cube-validator.test.ts
index c70aa16f422f6..8f5fcf277b125 100644
--- a/packages/cubejs-schema-compiler/test/unit/cube-validator.test.ts
+++ b/packages/cubejs-schema-compiler/test/unit/cube-validator.test.ts
@@ -1292,4 +1292,139 @@ describe('Cube Validation', () => {
       expect(result.error).toBeTruthy();
     });
   });
+
+  describe('Custom date format for time dimensions', () => {
+    it('time dimension with valid custom date format - correct', async () => {
+      const cubeValidator = new CubeValidator(new CubeSymbols());
+      const cube = {
+        name: 'name',
+        sql: () => 'SELECT * FROM public.Orders',
+        dimensions: {
+          createdAt: {
+            sql: () => 'created_at',
+            type: 'time',
+            format: 'yyyy-MM-dd'
+          },
+        },
+        fileName: 'fileName',
+      };
+
+      const validationResult = cubeValidator.validate(cube, new ConsoleErrorReporter());
+      expect(validationResult.error).toBeFalsy();
+    });
+
+    it('time dimension with complex date format - correct', async () => {
+      const cubeValidator = new CubeValidator(new CubeSymbols());
+      const cube = {
+        name: 'name',
+        sql: () => 'SELECT * FROM public.Orders',
+        dimensions: {
+          createdAt: {
+            sql: () => 'created_at',
+            type: 'time',
+            format: 'dd/mm/yyyy hh:nn:ss'
+          },
+        },
+        fileName: 'fileName',
+      };
+
+      const validationResult = cubeValidator.validate(cube, new ConsoleErrorReporter());
+      expect(validationResult.error).toBeFalsy();
+    });
+
+    it('time dimension with quoted literals in format - correct', async () => {
+      const cubeValidator = new CubeValidator(new CubeSymbols());
+      const cube = {
+        name: 'name',
+        sql: () => 'SELECT * FROM public.Orders',
+        dimensions: {
+          createdAt: {
+            sql: () => 'created_at',
+            type: 'time',
+            format: 'yyyy "Year" mm "Month"'
+          },
+        },
+        fileName: 'fileName',
+      };
+
+      const validationResult = cubeValidator.validate(cube, new ConsoleErrorReporter());
+      expect(validationResult.error).toBeFalsy();
+    });
+
+    it('time dimension with standard format - correct', async () => {
+      const cubeValidator = new CubeValidator(new CubeSymbols());
+      const cube = {
+        name: 'name',
+        sql: () => 'SELECT * FROM public.Orders',
+        dimensions: {
+          createdAt: {
+            sql: () => 'created_at',
+            type: 'time',
+            format: 'id'
+          },
+        },
+        fileName: 'fileName',
+      };
+
+      const validationResult = cubeValidator.validate(cube, new ConsoleErrorReporter());
+      expect(validationResult.error).toBeFalsy();
+    });
+
+    it('time dimension with invalid format (no specifiers) - error', async () => {
+      const cubeValidator = new CubeValidator(new CubeSymbols());
+      const cube = {
+        name: 'name',
+        sql: () => 'SELECT * FROM public.Orders',
+        dimensions: {
+          createdAt: {
+            sql: () => 'created_at',
+            type: 'time',
+            format: 'invalid'
+          },
+        },
+        fileName: 'fileName',
+      };
+
+      const validationResult = cubeValidator.validate(cube, new ConsoleErrorReporter());
+      expect(validationResult.error).toBeTruthy();
+    });
+
+    it('time dimension with invalid characters in format - error', async () => {
+      const cubeValidator = new CubeValidator(new CubeSymbols());
+      const cube = {
+        name: 'name',
+        sql: () => 'SELECT * FROM public.Orders',
+        dimensions: {
+          createdAt: {
+            sql: () => 'created_at',
+            type: 'time',
+            format: 'yyyy@mm#dd'
+          },
+        },
+        fileName: 'fileName',
+      };
+
+      const validationResult = cubeValidator.validate(cube, new ConsoleErrorReporter());
+      expect(validationResult.error).toBeTruthy();
+    });
+
+    it('non-time dimension with date format string - error', async () => {
+      const cubeValidator = new CubeValidator(new CubeSymbols());
+      const cube = {
+        name: 'name',
+        sql: () => 'SELECT * FROM public.Orders',
+        dimensions: {
+          status: {
+            sql: () => 'status',
+            type: 'string',
+            format: 'yyyy-MM-dd'
+          },
+        },
+        fileName: 'fileName',
+      };
+
+      const validationResult = cubeValidator.validate(cube, new ConsoleErrorReporter());
+      expect(validationResult.error).toBeTruthy();
+    });
+  });
 });

From e3f49bdff8d34b38f34739f277049d323ae5b077 Mon Sep 17 00:00:00 2001
From: Dmitry Patsura <talk@dmtry.me>
Date: Mon, 1 Dec 2025 12:19:58 +0100
Subject: [PATCH 2/7] chore: update openspec/client-core

---
 packages/cubejs-api-gateway/openspec.yml        | 17 ++++++++++++++++-
 packages/cubejs-client-core/src/types.ts        |  8 +++++++-
 .../src/compiler/CubeToMetaTransformer.ts       |  4 +++-
 3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/packages/cubejs-api-gateway/openspec.yml b/packages/cubejs-api-gateway/openspec.yml
index f83b0642b32af..dad06003aed81 100644
--- a/packages/cubejs-api-gateway/openspec.yml
+++ b/packages/cubejs-api-gateway/openspec.yml
@@ -291,11 +291,26 @@ components:
       required:
         - label
         - type
+    V1CubeMetaCustomDateFormat:
+      type: "object"
+      description: Custom date format for time dimensions
+      properties:
+        type:
+          type: "string"
+          enum: ["custom-date"]
+          description: Type of the format (must be 'custom-date')
+        value:
+          type: "string"
+          description: Date format string (e.g., 'yyyy-MM-dd', 'dd/mm/yyyy hh:nn:ss')
+      required:
+        - type
+        - value
     V1CubeMetaFormat:
       oneOf:
         - $ref: "#/components/schemas/V1CubeMetaSimpleFormat"
         - $ref: "#/components/schemas/V1CubeMetaLinkFormat"
-      description: Format of dimension - can be either a simple string format or an object with link configuration
+        - $ref: "#/components/schemas/V1CubeMetaCustomDateFormat"
+      description: Format of dimension - can be a simple string format, a link configuration, or a custom date format
     V1MetaResponse:
       type: "object"
       properties:
diff --git a/packages/cubejs-client-core/src/types.ts b/packages/cubejs-client-core/src/types.ts
index db50bd61fcd59..9c1a13407c021 100644
--- a/packages/cubejs-client-core/src/types.ts
+++ b/packages/cubejs-client-core/src/types.ts
@@ -15,12 +15,17 @@ export type GranularityAnnotation = {
   origin?: string;
 };
 
+export type DimensionCustomDateFormat = { type: 'custom-date'; value: string };
+export type DimensionLinkFormat = { type: 'link'; label: string };
+export type DimensionFormat = 'percent' | 'currency' | 'number' | 'imageUrl' | 'id' | 'link'
+  | DimensionLinkFormat | DimensionCustomDateFormat;
+
 export type Annotation = {
   title: string;
   shortTitle: string;
   type: string;
   meta?: any;
-  format?: 'currency' | 'percent' | 'number';
+  format?: DimensionFormat;
   drillMembers?: any[];
   drillMembersGrouped?: any;
   granularity?: GranularityAnnotation;
@@ -388,6 +393,7 @@ export type CubeTimeDimensionGranularity = {
 export type BaseCubeDimension = BaseCubeMember & {
   primaryKey?: boolean;
   suggestFilterValues: boolean;
+  format?: DimensionFormat;
 };
 
 export type CubeTimeDimension = BaseCubeDimension &
diff --git a/packages/cubejs-schema-compiler/src/compiler/CubeToMetaTransformer.ts b/packages/cubejs-schema-compiler/src/compiler/CubeToMetaTransformer.ts
index 710e11c88e64f..ec26fff1ccb46 100644
--- a/packages/cubejs-schema-compiler/src/compiler/CubeToMetaTransformer.ts
+++ b/packages/cubejs-schema-compiler/src/compiler/CubeToMetaTransformer.ts
@@ -77,7 +77,9 @@ export type MeasureConfig = {
   public: boolean;
 };
 
-export type DimensionFormat = string | { type: string; label?: string; value?: string };
+export type DimensionCustomDateFormat = { type: 'custom-date'; value: string };
+export type DimensionLinkFormat = { type: 'link'; label?: string };
+export type DimensionFormat = string | DimensionLinkFormat | DimensionCustomDateFormat;
 
 export type DimensionConfig = {
   name: string;

From eced2da5a7cef17a7ed3ce2e8cfbc1c3bbd210be Mon Sep 17 00:00:00 2001
From: Dmitry Patsura <talk@dmtry.me>
Date: Mon, 1 Dec 2025 12:32:45 +0100
Subject: [PATCH 3/7] feat(cubeclient): Support custom date formatting

---
 rust/.gitignore                               |  1 +
 .../cubeclient/.openapi-generator/FILES       |  1 +
 rust/cubesql/cubeclient/src/models/mod.rs     |  4 ++
 .../models/v1_cube_meta_custom_date_format.rs | 42 +++++++++++++++++++
 .../src/models/v1_cube_meta_format.rs         |  7 +++-
 5 files changed, 53 insertions(+), 2 deletions(-)
 create mode 100644 rust/.gitignore
 create mode 100644 rust/cubesql/cubeclient/src/models/v1_cube_meta_custom_date_format.rs

diff --git a/rust/.gitignore b/rust/.gitignore
new file mode 100644
index 0000000000000..485dee64bcfb4
--- /dev/null
+++ b/rust/.gitignore
@@ -0,0 +1 @@
+.idea
diff --git a/rust/cubesql/cubeclient/.openapi-generator/FILES b/rust/cubesql/cubeclient/.openapi-generator/FILES
index 91667358992ba..c7e34701c4914 100644
--- a/rust/cubesql/cubeclient/.openapi-generator/FILES
+++ b/rust/cubesql/cubeclient/.openapi-generator/FILES
@@ -2,6 +2,7 @@
 src/lib.rs
 src/models/mod.rs
 src/models/v1_cube_meta.rs
+src/models/v1_cube_meta_custom_date_format.rs
 src/models/v1_cube_meta_dimension.rs
 src/models/v1_cube_meta_dimension_granularity.rs
 src/models/v1_cube_meta_folder.rs
diff --git a/rust/cubesql/cubeclient/src/models/mod.rs b/rust/cubesql/cubeclient/src/models/mod.rs
index 5ee41ef768ef0..b37d0f590d321 100644
--- a/rust/cubesql/cubeclient/src/models/mod.rs
+++ b/rust/cubesql/cubeclient/src/models/mod.rs
@@ -1,5 +1,9 @@
 pub mod v1_cube_meta;
 pub use self::v1_cube_meta::V1CubeMeta;
+pub mod v1_cube_meta_custom_date_format;
+pub use self::v1_cube_meta_custom_date_format::V1CubeMetaCustomDateFormat;
+// problem with code-gen, let's rename it as re-export
+pub use self::v1_cube_meta_custom_date_format::Type as V1CubeMetaCustomDateFormatType;
 pub mod v1_cube_meta_dimension;
 pub use self::v1_cube_meta_dimension::V1CubeMetaDimension;
 pub mod v1_cube_meta_dimension_granularity;
diff --git a/rust/cubesql/cubeclient/src/models/v1_cube_meta_custom_date_format.rs b/rust/cubesql/cubeclient/src/models/v1_cube_meta_custom_date_format.rs
new file mode 100644
index 0000000000000..b182be1e65891
--- /dev/null
+++ b/rust/cubesql/cubeclient/src/models/v1_cube_meta_custom_date_format.rs
@@ -0,0 +1,42 @@
+/*
+ * Cube.js
+ *
+ * Cube.js Swagger Schema
+ *
+ * The version of the OpenAPI document: 1.0.0
+ *
+ * Generated by: https://openapi-generator.tech
+ */
+
+use crate::models;
+use serde::{Deserialize, Serialize};
+
+/// V1CubeMetaCustomDateFormat : Custom date format for time dimensions
+#[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
+pub struct V1CubeMetaCustomDateFormat {
+    /// Type of the format (must be 'custom-date')
+    #[serde(rename = "type")]
+    pub r#type: Type,
+    /// Date format string (e.g., 'yyyy-MM-dd', 'dd/mm/yyyy hh:nn:ss')
+    #[serde(rename = "value")]
+    pub value: String,
+}
+
+impl V1CubeMetaCustomDateFormat {
+    /// Custom date format for time dimensions
+    pub fn new(r#type: Type, value: String) -> V1CubeMetaCustomDateFormat {
+        V1CubeMetaCustomDateFormat { r#type, value }
+    }
+}
+/// Type of the format (must be 'custom-date')
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Ord, PartialOrd, Hash, Serialize, Deserialize)]
+pub enum Type {
+    #[serde(rename = "custom-date")]
+    CustomDate,
+}
+
+impl Default for Type {
+    fn default() -> Type {
+        Self::CustomDate
+    }
+}
diff --git a/rust/cubesql/cubeclient/src/models/v1_cube_meta_format.rs b/rust/cubesql/cubeclient/src/models/v1_cube_meta_format.rs
index 881d388975753..6a839db0b92ea 100644
--- a/rust/cubesql/cubeclient/src/models/v1_cube_meta_format.rs
+++ b/rust/cubesql/cubeclient/src/models/v1_cube_meta_format.rs
@@ -11,13 +11,14 @@
 use crate::models;
 use serde::{Deserialize, Serialize};
 
-/// V1CubeMetaFormat : Format of dimension - can be either a simple string format or an object with link configuration
-/// Format of dimension - can be either a simple string format or an object with link configuration
+/// V1CubeMetaFormat : Format of dimension - can be a simple string format, a link configuration, or a custom date format
+/// Format of dimension - can be a simple string format, a link configuration, or a custom date format
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
 #[serde(untagged)]
 pub enum V1CubeMetaFormat {
     V1CubeMetaSimpleFormat(models::V1CubeMetaSimpleFormat),
     V1CubeMetaLinkFormat(Box<models::V1CubeMetaLinkFormat>),
+    V1CubeMetaCustomDateFormat(Box<models::V1CubeMetaCustomDateFormat>),
 }
 
 impl Default for V1CubeMetaFormat {
@@ -30,6 +31,8 @@ impl Default for V1CubeMetaFormat {
 pub enum Type {
     #[serde(rename = "link")]
     Link,
+    #[serde(rename = "custom-date")]
+    CustomDate,
 }
 
 impl Default for Type {

From fa1e97657dcc3a4f34a22e7e23c935b93d84c4ec Mon Sep 17 00:00:00 2001
From: Dmitry Patsura <talk@dmtry.me>
Date: Mon, 1 Dec 2025 13:50:50 +0100
Subject: [PATCH 4/7] chore: rename to custom-time

---
 packages/cubejs-api-gateway/openspec.yml      | 14 +++++------
 packages/cubejs-client-core/src/types.ts      |  4 ++--
 .../src/compiler/CubeToMetaTransformer.ts     |  6 ++---
 .../src/compiler/CubeValidator.ts             | 20 ++++++++--------
 .../test/unit/cube-validator.test.ts          |  8 +++----
 .../cubeclient/.openapi-generator/FILES       |  2 +-
 rust/cubesql/cubeclient/src/models/mod.rs     |  6 ++---
 ....rs => v1_cube_meta_custom_time_format.rs} | 24 +++++++++----------
 .../src/models/v1_cube_meta_format.rs         | 10 ++++----
 9 files changed, 47 insertions(+), 47 deletions(-)
 rename rust/cubesql/cubeclient/src/models/{v1_cube_meta_custom_date_format.rs => v1_cube_meta_custom_time_format.rs} (50%)

diff --git a/packages/cubejs-api-gateway/openspec.yml b/packages/cubejs-api-gateway/openspec.yml
index dad06003aed81..92cfa399bcb21 100644
--- a/packages/cubejs-api-gateway/openspec.yml
+++ b/packages/cubejs-api-gateway/openspec.yml
@@ -291,17 +291,17 @@ components:
       required:
         - label
         - type
-    V1CubeMetaCustomDateFormat:
+    V1CubeMetaCustomTimeFormat:
       type: "object"
-      description: Custom date format for time dimensions
+      description: Custom time format for time dimensions
       properties:
         type:
           type: "string"
-          enum: ["custom-date"]
-          description: Type of the format (must be 'custom-date')
+          enum: ["custom-time"]
+          description: Type of the format (must be 'custom-time')
         value:
           type: "string"
-          description: Date format string (e.g., 'yyyy-MM-dd', 'dd/mm/yyyy hh:nn:ss')
+          description: Time format string (e.g., 'yyyy-MM-dd', 'dd/mm/yyyy hh:nn:ss')
       required:
         - type
         - value
@@ -309,8 +309,8 @@ components:
       oneOf:
         - $ref: "#/components/schemas/V1CubeMetaSimpleFormat"
         - $ref: "#/components/schemas/V1CubeMetaLinkFormat"
-        - $ref: "#/components/schemas/V1CubeMetaCustomDateFormat"
-      description: Format of dimension - can be a simple string format, a link configuration, or a custom date format
+        - $ref: "#/components/schemas/V1CubeMetaCustomTimeFormat"
+      description: Format of dimension - can be a simple string format, a link configuration, or a custom time format
     V1MetaResponse:
       type: "object"
       properties:
diff --git a/packages/cubejs-client-core/src/types.ts b/packages/cubejs-client-core/src/types.ts
index 9c1a13407c021..5539644c7b955 100644
--- a/packages/cubejs-client-core/src/types.ts
+++ b/packages/cubejs-client-core/src/types.ts
@@ -15,10 +15,10 @@ export type GranularityAnnotation = {
   origin?: string;
 };
 
-export type DimensionCustomDateFormat = { type: 'custom-date'; value: string };
+export type DimensionCustomTimeFormat = { type: 'custom-time'; value: string };
 export type DimensionLinkFormat = { type: 'link'; label: string };
 export type DimensionFormat = 'percent' | 'currency' | 'number' | 'imageUrl' | 'id' | 'link'
-  | DimensionLinkFormat | DimensionCustomDateFormat;
+  | DimensionLinkFormat | DimensionCustomTimeFormat;
 
 export type Annotation = {
   title: string;
diff --git a/packages/cubejs-schema-compiler/src/compiler/CubeToMetaTransformer.ts b/packages/cubejs-schema-compiler/src/compiler/CubeToMetaTransformer.ts
index ec26fff1ccb46..3ba0d9db2c2e8 100644
--- a/packages/cubejs-schema-compiler/src/compiler/CubeToMetaTransformer.ts
+++ b/packages/cubejs-schema-compiler/src/compiler/CubeToMetaTransformer.ts
@@ -77,9 +77,9 @@ export type MeasureConfig = {
   public: boolean;
 };
 
-export type DimensionCustomDateFormat = { type: 'custom-date'; value: string };
+export type DimensionCustomTimeFormat = { type: 'custom-time'; value: string };
 export type DimensionLinkFormat = { type: 'link'; label?: string };
-export type DimensionFormat = string | DimensionLinkFormat | DimensionCustomDateFormat;
+export type DimensionFormat = string | DimensionLinkFormat | DimensionCustomTimeFormat;
 
 export type DimensionConfig = {
   name: string;
@@ -411,6 +411,6 @@ export class CubeToMetaTransformer implements CompilerInterface {
       return format;
     }
 
-    return { type: 'custom-date', value: format };
+    return { type: 'custom-time', value: format };
   }
 }
diff --git a/packages/cubejs-schema-compiler/src/compiler/CubeValidator.ts b/packages/cubejs-schema-compiler/src/compiler/CubeValidator.ts
index 078eada13a966..aab05ddf17391 100644
--- a/packages/cubejs-schema-compiler/src/compiler/CubeValidator.ts
+++ b/packages/cubejs-schema-compiler/src/compiler/CubeValidator.ts
@@ -119,10 +119,10 @@ const formatSchema = Joi.alternatives([
   })
 ]);
 
-const DATE_FORMAT_SPECIFIERS = new Set(['d', 'm', 'y', 'h', 'n', 's', 'q', 'w']);
-const DATE_FORMAT_SEPARATORS = new Set(['-', '/', ':', '.', ',', ' ']);
+const TIME_FORMAT_SPECIFIERS = new Set(['d', 'm', 'y', 'h', 'n', 's', 'q', 'w']);
+const TIME_FORMAT_SEPARATORS = new Set(['-', '/', ':', '.', ',', ' ']);
 
-const customDateFormatSchema = Joi.string().custom((value, helper) => {
+const customTimeFormatSchema = Joi.string().custom((value, helper) => {
   const invalidChars: string[] = [];
   let hasSpecifier = false;
 
@@ -135,21 +135,21 @@ const customDateFormatSchema = Joi.string().custom((value, helper) => {
     if (char === '"' || char === '\'') {
       const closeIndex = value.indexOf(char, i + 1);
       if (closeIndex === -1) {
-        return helper.message({ custom: `Invalid date format "${value}". Unclosed quote at position ${i}` });
+        return helper.message({ custom: `Invalid time format "${value}". Unclosed quote at position ${i}` });
       }
 
       i = closeIndex + 1;
     } else if (char === '[') {
       const closeIndex = value.indexOf(']', i + 1);
       if (closeIndex === -1) {
-        return helper.message({ custom: `Invalid date format "${value}". Unclosed bracket at position ${i}` });
+        return helper.message({ custom: `Invalid time format "${value}". Unclosed bracket at position ${i}` });
       }
 
       i = closeIndex + 1;
-    } else if (DATE_FORMAT_SPECIFIERS.has(char.toLowerCase())) {
+    } else if (TIME_FORMAT_SPECIFIERS.has(char.toLowerCase())) {
       hasSpecifier = true;
       i++;
-    } else if (DATE_FORMAT_SEPARATORS.has(char)) {
+    } else if (TIME_FORMAT_SEPARATORS.has(char)) {
       i++;
     } else if (char.toUpperCase() === 'A' || char.toUpperCase() === 'P') {
       i++;
@@ -160,11 +160,11 @@ const customDateFormatSchema = Joi.string().custom((value, helper) => {
   }
 
   if (!hasSpecifier) {
-    return helper.message({ custom: `Invalid date format "${value}". Format must contain at least one date/time specifier (d, m, y, h, n, s, q, w)` });
+    return helper.message({ custom: `Invalid time format "${value}". Format must contain at least one date/time specifier (d, m, y, h, n, s, q, w)` });
   }
 
   if (invalidChars.length > 0) {
-    return helper.message({ custom: `Invalid date format "${value}". Contains invalid characters: "${invalidChars.join('')}". Use quotes for literal text.` });
+    return helper.message({ custom: `Invalid time format "${value}". Contains invalid characters: "${invalidChars.join('')}". Use quotes for literal text.` });
   }
 
   return value;
@@ -172,7 +172,7 @@ const customDateFormatSchema = Joi.string().custom((value, helper) => {
 
 const timeFormatSchema = Joi.alternatives([
   formatSchema,
-  customDateFormatSchema
+  customTimeFormatSchema
 ]);
 
 const BaseDimensionWithoutSubQuery = {
diff --git a/packages/cubejs-schema-compiler/test/unit/cube-validator.test.ts b/packages/cubejs-schema-compiler/test/unit/cube-validator.test.ts
index 8f5fcf277b125..d32abdafe82d2 100644
--- a/packages/cubejs-schema-compiler/test/unit/cube-validator.test.ts
+++ b/packages/cubejs-schema-compiler/test/unit/cube-validator.test.ts
@@ -1293,8 +1293,8 @@ describe('Cube Validation', () => {
     });
   });
 
-  describe('Custom date format for time dimensions', () => {
-    it('time dimension with valid custom date format - correct', async () => {
+  describe('Custom time format for time dimensions', () => {
+    it('time dimension with valid custom time format - correct', async () => {
       const cubeValidator = new CubeValidator(new CubeSymbols());
       const cube = {
         name: 'name',
@@ -1313,7 +1313,7 @@ describe('Cube Validation', () => {
       expect(validationResult.error).toBeFalsy();
     });
 
-    it('time dimension with complex date format - correct', async () => {
+    it('time dimension with complex time format - correct', async () => {
       const cubeValidator = new CubeValidator(new CubeSymbols());
       const cube = {
         name: 'name',
@@ -1408,7 +1408,7 @@ describe('Cube Validation', () => {
       expect(validationResult.error).toBeTruthy();
     });
 
-    it('non-time dimension with date format string - error', async () => {
+    it('non-time dimension with time format string - error', async () => {
       const cubeValidator = new CubeValidator(new CubeSymbols());
       const cube = {
         name: 'name',
diff --git a/rust/cubesql/cubeclient/.openapi-generator/FILES b/rust/cubesql/cubeclient/.openapi-generator/FILES
index c7e34701c4914..c9d7d2f8207bc 100644
--- a/rust/cubesql/cubeclient/.openapi-generator/FILES
+++ b/rust/cubesql/cubeclient/.openapi-generator/FILES
@@ -2,7 +2,7 @@
 src/lib.rs
 src/models/mod.rs
 src/models/v1_cube_meta.rs
-src/models/v1_cube_meta_custom_date_format.rs
+src/models/v1_cube_meta_custom_time_format.rs
 src/models/v1_cube_meta_dimension.rs
 src/models/v1_cube_meta_dimension_granularity.rs
 src/models/v1_cube_meta_folder.rs
diff --git a/rust/cubesql/cubeclient/src/models/mod.rs b/rust/cubesql/cubeclient/src/models/mod.rs
index b37d0f590d321..8b336672b31b2 100644
--- a/rust/cubesql/cubeclient/src/models/mod.rs
+++ b/rust/cubesql/cubeclient/src/models/mod.rs
@@ -1,9 +1,9 @@
 pub mod v1_cube_meta;
 pub use self::v1_cube_meta::V1CubeMeta;
-pub mod v1_cube_meta_custom_date_format;
-pub use self::v1_cube_meta_custom_date_format::V1CubeMetaCustomDateFormat;
+pub mod v1_cube_meta_custom_time_format;
+pub use self::v1_cube_meta_custom_time_format::V1CubeMetaCustomTimeFormat;
 // problem with code-gen, let's rename it as re-export
-pub use self::v1_cube_meta_custom_date_format::Type as V1CubeMetaCustomDateFormatType;
+pub use self::v1_cube_meta_custom_time_format::Type as V1CubeMetaCustomTimeFormatType;
 pub mod v1_cube_meta_dimension;
 pub use self::v1_cube_meta_dimension::V1CubeMetaDimension;
 pub mod v1_cube_meta_dimension_granularity;
diff --git a/rust/cubesql/cubeclient/src/models/v1_cube_meta_custom_date_format.rs b/rust/cubesql/cubeclient/src/models/v1_cube_meta_custom_time_format.rs
similarity index 50%
rename from rust/cubesql/cubeclient/src/models/v1_cube_meta_custom_date_format.rs
rename to rust/cubesql/cubeclient/src/models/v1_cube_meta_custom_time_format.rs
index b182be1e65891..909c68ae8767f 100644
--- a/rust/cubesql/cubeclient/src/models/v1_cube_meta_custom_date_format.rs
+++ b/rust/cubesql/cubeclient/src/models/v1_cube_meta_custom_time_format.rs
@@ -11,32 +11,32 @@
 use crate::models;
 use serde::{Deserialize, Serialize};
 
-/// V1CubeMetaCustomDateFormat : Custom date format for time dimensions
+/// V1CubeMetaCustomTimeFormat : Custom time format for time dimensions
 #[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
-pub struct V1CubeMetaCustomDateFormat {
-    /// Type of the format (must be 'custom-date')
+pub struct V1CubeMetaCustomTimeFormat {
+    /// Type of the format (must be 'custom-time')
     #[serde(rename = "type")]
     pub r#type: Type,
-    /// Date format string (e.g., 'yyyy-MM-dd', 'dd/mm/yyyy hh:nn:ss')
+    /// Time format string (e.g., 'yyyy-MM-dd', 'dd/mm/yyyy hh:nn:ss')
     #[serde(rename = "value")]
     pub value: String,
 }
 
-impl V1CubeMetaCustomDateFormat {
-    /// Custom date format for time dimensions
-    pub fn new(r#type: Type, value: String) -> V1CubeMetaCustomDateFormat {
-        V1CubeMetaCustomDateFormat { r#type, value }
+impl V1CubeMetaCustomTimeFormat {
+    /// Custom time format for time dimensions
+    pub fn new(r#type: Type, value: String) -> V1CubeMetaCustomTimeFormat {
+        V1CubeMetaCustomTimeFormat { r#type, value }
     }
 }
-/// Type of the format (must be 'custom-date')
+/// Type of the format (must be 'custom-time')
 #[derive(Clone, Copy, Debug, Eq, PartialEq, Ord, PartialOrd, Hash, Serialize, Deserialize)]
 pub enum Type {
-    #[serde(rename = "custom-date")]
-    CustomDate,
+    #[serde(rename = "custom-time")]
+    CustomTime,
 }
 
 impl Default for Type {
     fn default() -> Type {
-        Self::CustomDate
+        Self::CustomTime
     }
 }
diff --git a/rust/cubesql/cubeclient/src/models/v1_cube_meta_format.rs b/rust/cubesql/cubeclient/src/models/v1_cube_meta_format.rs
index 6a839db0b92ea..c1625fcc8f62e 100644
--- a/rust/cubesql/cubeclient/src/models/v1_cube_meta_format.rs
+++ b/rust/cubesql/cubeclient/src/models/v1_cube_meta_format.rs
@@ -11,14 +11,14 @@
 use crate::models;
 use serde::{Deserialize, Serialize};
 
-/// V1CubeMetaFormat : Format of dimension - can be a simple string format, a link configuration, or a custom date format
-/// Format of dimension - can be a simple string format, a link configuration, or a custom date format
+/// V1CubeMetaFormat : Format of dimension - can be a simple string format, a link configuration, or a custom time format
+/// Format of dimension - can be a simple string format, a link configuration, or a custom time format
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
 #[serde(untagged)]
 pub enum V1CubeMetaFormat {
     V1CubeMetaSimpleFormat(models::V1CubeMetaSimpleFormat),
     V1CubeMetaLinkFormat(Box<models::V1CubeMetaLinkFormat>),
-    V1CubeMetaCustomDateFormat(Box<models::V1CubeMetaCustomDateFormat>),
+    V1CubeMetaCustomTimeFormat(Box<models::V1CubeMetaCustomTimeFormat>),
 }
 
 impl Default for V1CubeMetaFormat {
@@ -31,8 +31,8 @@ impl Default for V1CubeMetaFormat {
 pub enum Type {
     #[serde(rename = "link")]
     Link,
-    #[serde(rename = "custom-date")]
-    CustomDate,
+    #[serde(rename = "custom-time")]
+    CustomTime,
 }
 
 impl Default for Type {

From 909b1f0cb991a586f71039c2140a69c58489b345 Mon Sep 17 00:00:00 2001
From: Dmitry Patsura <talk@dmtry.me>
Date: Tue, 2 Dec 2025 11:35:08 +0100
Subject: [PATCH 5/7] chore: d3 time format

---
 packages/cubejs-api-gateway/openspec.yml      |  2 +-
 .../src/compiler/CubeValidator.ts             | 65 ++++++++-------
 .../test/unit/cube-validator.test.ts          | 79 ++++++++++++++++---
 3 files changed, 105 insertions(+), 41 deletions(-)

diff --git a/packages/cubejs-api-gateway/openspec.yml b/packages/cubejs-api-gateway/openspec.yml
index 92cfa399bcb21..53359a9023113 100644
--- a/packages/cubejs-api-gateway/openspec.yml
+++ b/packages/cubejs-api-gateway/openspec.yml
@@ -301,7 +301,7 @@ components:
           description: Type of the format (must be 'custom-time')
         value:
           type: "string"
-          description: Time format string (e.g., 'yyyy-MM-dd', 'dd/mm/yyyy hh:nn:ss')
+          description: "POSIX strftime format string (IEEE Std 1003.1 / POSIX.1) with d3-time-format extensions (e.g., '%Y-%m-%d', '%d/%m/%Y %H:%M:%S'). See https://pubs.opengroup.org/onlinepubs/009695399/functions/strptime.html and https://d3js.org/d3-time-format"
       required:
         - type
         - value
diff --git a/packages/cubejs-schema-compiler/src/compiler/CubeValidator.ts b/packages/cubejs-schema-compiler/src/compiler/CubeValidator.ts
index aab05ddf17391..4b4da9dc01d27 100644
--- a/packages/cubejs-schema-compiler/src/compiler/CubeValidator.ts
+++ b/packages/cubejs-schema-compiler/src/compiler/CubeValidator.ts
@@ -119,52 +119,59 @@ const formatSchema = Joi.alternatives([
   })
 ]);
 
-const TIME_FORMAT_SPECIFIERS = new Set(['d', 'm', 'y', 'h', 'n', 's', 'q', 'w']);
-const TIME_FORMAT_SEPARATORS = new Set(['-', '/', ':', '.', ',', ' ']);
+// POSIX strftime specification (IEEE Std 1003.1 / POSIX.1) with d3-time-format extensions
+// See: https://pubs.opengroup.org/onlinepubs/009695399/functions/strptime.html
+// See: https://d3js.org/d3-time-format
+const STRPTIME_SPECIFIERS = new Set([
+  // POSIX standard specifiers
+  'a', 'A', 'b', 'B', 'c', 'd', 'H', 'I', 'j', 'm',
+  'M', 'n', 'p', 'S', 't', 'U', 'w', 'W', 'x', 'X',
+  'y', 'Y', 'Z', '%',
+  // d3-time-format extensions
+  'e', // space-padded day of month
+  'f', // microseconds
+  'g', // ISO 8601 year without century
+  'G', // ISO 8601 year with century
+  'L', // milliseconds
+  'q', // quarter
+  'Q', // milliseconds since UNIX epoch
+  's', // seconds since UNIX epoch
+  'u', // Monday-based weekday [1,7]
+  'V', // ISO 8601 week number
+]);
 
 const customTimeFormatSchema = Joi.string().custom((value, helper) => {
-  const invalidChars: string[] = [];
   let hasSpecifier = false;
-
   let i = 0;
 
   while (i < value.length) {
-    const char = value[i];
+    if (value[i] === '%') {
+      if (i + 1 >= value.length) {
+        return helper.message({ custom: `Invalid strptime format "${value}". Incomplete specifier at end of string` });
+      }
 
-    // Handle quoted literals (skip content inside quotes or brackets)
-    if (char === '"' || char === '\'') {
-      const closeIndex = value.indexOf(char, i + 1);
-      if (closeIndex === -1) {
-        return helper.message({ custom: `Invalid time format "${value}". Unclosed quote at position ${i}` });
+      const specifier = value[i + 1];
+
+      if (!STRPTIME_SPECIFIERS.has(specifier)) {
+        return helper.message({ custom: `Invalid strptime format "${value}". Unknown specifier '%${specifier}'` });
       }
 
-      i = closeIndex + 1;
-    } else if (char === '[') {
-      const closeIndex = value.indexOf(']', i + 1);
-      if (closeIndex === -1) {
-        return helper.message({ custom: `Invalid time format "${value}". Unclosed bracket at position ${i}` });
+      // %% is an escape for literal %, not a date/time specifier
+      if (specifier !== '%') {
+        hasSpecifier = true;
       }
 
-      i = closeIndex + 1;
-    } else if (TIME_FORMAT_SPECIFIERS.has(char.toLowerCase())) {
-      hasSpecifier = true;
-      i++;
-    } else if (TIME_FORMAT_SEPARATORS.has(char)) {
-      i++;
-    } else if (char.toUpperCase() === 'A' || char.toUpperCase() === 'P') {
-      i++;
+      i += 2;
     } else {
-      invalidChars.push(char);
+      // Any other character is treated as literal text
       i++;
     }
   }
 
   if (!hasSpecifier) {
-    return helper.message({ custom: `Invalid time format "${value}". Format must contain at least one date/time specifier (d, m, y, h, n, s, q, w)` });
-  }
-
-  if (invalidChars.length > 0) {
-    return helper.message({ custom: `Invalid time format "${value}". Contains invalid characters: "${invalidChars.join('')}". Use quotes for literal text.` });
+    return helper.message({
+      custom: `Invalid strptime format "${value}". Format must contain at least one strptime specifier (e.g., %Y, %m, %d)`
+    });
   }
 
   return value;
diff --git a/packages/cubejs-schema-compiler/test/unit/cube-validator.test.ts b/packages/cubejs-schema-compiler/test/unit/cube-validator.test.ts
index d32abdafe82d2..7a665ab31e89f 100644
--- a/packages/cubejs-schema-compiler/test/unit/cube-validator.test.ts
+++ b/packages/cubejs-schema-compiler/test/unit/cube-validator.test.ts
@@ -1293,8 +1293,8 @@ describe('Cube Validation', () => {
     });
   });
 
-  describe('Custom time format for time dimensions', () => {
-    it('time dimension with valid custom time format - correct', async () => {
+  describe('Custom time format for time dimensions (strptime)', () => {
+    it('time dimension with valid strptime format - correct', async () => {
       const cubeValidator = new CubeValidator(new CubeSymbols());
       const cube = {
         name: 'name',
@@ -1303,7 +1303,7 @@ describe('Cube Validation', () => {
           createdAt: {
             sql: () => 'created_at',
             type: 'time',
-            format: 'yyyy-MM-dd'
+            format: '%Y-%m-%d'
           },
         },
         fileName: 'fileName',
@@ -1313,7 +1313,7 @@ describe('Cube Validation', () => {
       expect(validationResult.error).toBeFalsy();
     });
 
-    it('time dimension with complex time format - correct', async () => {
+    it('time dimension with complex strptime format - correct', async () => {
       const cubeValidator = new CubeValidator(new CubeSymbols());
       const cube = {
         name: 'name',
@@ -1322,7 +1322,7 @@ describe('Cube Validation', () => {
           createdAt: {
             sql: () => 'created_at',
             type: 'time',
-            format: 'dd/mm/yyyy hh:nn:ss'
+            format: '%d/%m/%Y %H:%M:%S'
           },
         },
         fileName: 'fileName',
@@ -1332,7 +1332,7 @@ describe('Cube Validation', () => {
       expect(validationResult.error).toBeFalsy();
     });
 
-    it('time dimension with quoted literals in format - correct', async () => {
+    it('time dimension with literal text in format - correct', async () => {
       const cubeValidator = new CubeValidator(new CubeSymbols());
       const cube = {
         name: 'name',
@@ -1341,7 +1341,26 @@ describe('Cube Validation', () => {
           createdAt: {
             sql: () => 'created_at',
             type: 'time',
-            format: 'yyyy "Year" mm "Month"'
+            format: '%Y Year %m Month'
+          },
+        },
+        fileName: 'fileName',
+      };
+
+      const validationResult = cubeValidator.validate(cube, new ConsoleErrorReporter());
+      expect(validationResult.error).toBeFalsy();
+    });
+
+    it('time dimension with escaped percent - correct', async () => {
+      const cubeValidator = new CubeValidator(new CubeSymbols());
+      const cube = {
+        name: 'name',
+        sql: () => 'SELECT * FROM public.Orders',
+        dimensions: {
+          createdAt: {
+            sql: () => 'created_at',
+            type: 'time',
+            format: '%Y-%m-%d %%'
           },
         },
         fileName: 'fileName',
@@ -1389,7 +1408,45 @@ describe('Cube Validation', () => {
       expect(validationResult.error).toBeTruthy();
     });
 
-    it('time dimension with invalid characters in format - error', async () => {
+    it('time dimension with invalid specifier - error', async () => {
+      const cubeValidator = new CubeValidator(new CubeSymbols());
+      const cube = {
+        name: 'name',
+        sql: () => 'SELECT * FROM public.Orders',
+        dimensions: {
+          createdAt: {
+            sql: () => 'created_at',
+            type: 'time',
+            format: '%Y-%K-%d'
+          },
+        },
+        fileName: 'fileName',
+      };
+
+      const validationResult = cubeValidator.validate(cube, new ConsoleErrorReporter());
+      expect(validationResult.error).toBeTruthy();
+    });
+
+    it('time dimension with incomplete specifier at end - error', async () => {
+      const cubeValidator = new CubeValidator(new CubeSymbols());
+      const cube = {
+        name: 'name',
+        sql: () => 'SELECT * FROM public.Orders',
+        dimensions: {
+          createdAt: {
+            sql: () => 'created_at',
+            type: 'time',
+            format: '%Y-%m-%'
+          },
+        },
+        fileName: 'fileName',
+      };
+
+      const validationResult = cubeValidator.validate(cube, new ConsoleErrorReporter());
+      expect(validationResult.error).toBeTruthy();
+    });
+
+    it('time dimension with only escaped percent - error', async () => {
       const cubeValidator = new CubeValidator(new CubeSymbols());
       const cube = {
         name: 'name',
@@ -1398,7 +1455,7 @@ describe('Cube Validation', () => {
           createdAt: {
             sql: () => 'created_at',
             type: 'time',
-            format: 'yyyy@mm#dd'
+            format: '%%'
           },
         },
         fileName: 'fileName',
@@ -1408,7 +1465,7 @@ describe('Cube Validation', () => {
       expect(validationResult.error).toBeTruthy();
     });
 
-    it('non-time dimension with time format string - error', async () => {
+    it('non-time dimension with strptime format string - error', async () => {
       const cubeValidator = new CubeValidator(new CubeSymbols());
       const cube = {
         name: 'name',
@@ -1417,7 +1474,7 @@ describe('Cube Validation', () => {
           status: {
             sql: () => 'status',
             type: 'string',
-            format: 'yyyy-MM-dd'
+            format: '%Y-%m-%d'
           },
         },
         fileName: 'fileName',

From aa7fbdfbf30486109f594af619713bc43a8476f9 Mon Sep 17 00:00:00 2001
From: Dmitry Patsura <talk@dmtry.me>
Date: Tue, 2 Dec 2025 12:14:14 +0100
Subject: [PATCH 6/7] chore: comment

---
 .../cubeclient/src/models/v1_cube_meta_custom_time_format.rs   | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/rust/cubesql/cubeclient/src/models/v1_cube_meta_custom_time_format.rs b/rust/cubesql/cubeclient/src/models/v1_cube_meta_custom_time_format.rs
index 909c68ae8767f..cc602e0e9815b 100644
--- a/rust/cubesql/cubeclient/src/models/v1_cube_meta_custom_time_format.rs
+++ b/rust/cubesql/cubeclient/src/models/v1_cube_meta_custom_time_format.rs
@@ -17,7 +17,8 @@ pub struct V1CubeMetaCustomTimeFormat {
     /// Type of the format (must be 'custom-time')
     #[serde(rename = "type")]
     pub r#type: Type,
-    /// Time format string (e.g., 'yyyy-MM-dd', 'dd/mm/yyyy hh:nn:ss')
+    /// POSIX strftime format string (IEEE Std 1003.1 / POSIX.1) with d3-time-format extensions (e.g., '%Y-%m-%d', '%d/%m/%Y %H:%M:%S').
+    /// See https://pubs.opengroup.org/onlinepubs/009695399/functions/strptime.html and https://d3js.org/d3-time-format
     #[serde(rename = "value")]
     pub value: String,
 }

From c3d38decf9226267a3ec1dfe82ff98aac0c9941c Mon Sep 17 00:00:00 2001
From: Dmitry Patsura <talk@dmtry.me>
Date: Tue, 2 Dec 2025 13:13:18 +0100
Subject: [PATCH 7/7] chore: better comment

---
 .../cubejs-schema-compiler/src/compiler/CubeValidator.ts  | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/packages/cubejs-schema-compiler/src/compiler/CubeValidator.ts b/packages/cubejs-schema-compiler/src/compiler/CubeValidator.ts
index 4b4da9dc01d27..6b515439ad0e4 100644
--- a/packages/cubejs-schema-compiler/src/compiler/CubeValidator.ts
+++ b/packages/cubejs-schema-compiler/src/compiler/CubeValidator.ts
@@ -122,7 +122,7 @@ const formatSchema = Joi.alternatives([
 // POSIX strftime specification (IEEE Std 1003.1 / POSIX.1) with d3-time-format extensions
 // See: https://pubs.opengroup.org/onlinepubs/009695399/functions/strptime.html
 // See: https://d3js.org/d3-time-format
-const STRPTIME_SPECIFIERS = new Set([
+const TIME_SPECIFIERS = new Set([
   // POSIX standard specifiers
   'a', 'A', 'b', 'B', 'c', 'd', 'H', 'I', 'j', 'm',
   'M', 'n', 'p', 'S', 't', 'U', 'w', 'W', 'x', 'X',
@@ -147,13 +147,13 @@ const customTimeFormatSchema = Joi.string().custom((value, helper) => {
   while (i < value.length) {
     if (value[i] === '%') {
       if (i + 1 >= value.length) {
-        return helper.message({ custom: `Invalid strptime format "${value}". Incomplete specifier at end of string` });
+        return helper.message({ custom: `Invalid time format "${value}". Incomplete specifier at end of string` });
       }
 
       const specifier = value[i + 1];
 
-      if (!STRPTIME_SPECIFIERS.has(specifier)) {
-        return helper.message({ custom: `Invalid strptime format "${value}". Unknown specifier '%${specifier}'` });
+      if (!TIME_SPECIFIERS.has(specifier)) {
+        return helper.message({ custom: `Invalid time format "${value}". Unknown specifier '%${specifier}'` });
       }
 
       // %% is an escape for literal %, not a date/time specifier