diff --git a/.claude/CLAUDE.md b/.claude/CLAUDE.md
new file mode 100644
index 000000000..2e53c4e6d
--- /dev/null
+++ b/.claude/CLAUDE.md
@@ -0,0 +1,108 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+This is the go-openapi fork of the testify testing package. The main goal is to remove external dependencies while maintaining a clean, focused API for testing in Go. This fork strips out unnecessary features (mocks, suite) and internalizes dependencies (go-spew, difflib) to ensure `github.com/go-openapi/testify/v2` is the only import needed.
+
+## Key Architecture
+
+### Core Packages
+- **assert**: Provides non-fatal test assertions (tests continue after failures)
+- **require**: Provides fatal test assertions (tests stop immediately on failure via `FailNow()`)
+- Both packages share similar APIs, but `require` wraps `assert` functions to make them fatal
+
+### Code Generation
+- The codebase uses code generation extensively via `_codegen/main.go`
+- Generated files include:
+  - `assert/assertion_format.go` - Format string variants of assertions
+  - `assert/assertion_forward.go` - Forwarded assertion methods
+  - `require/require.go` - Require variants of all assert functions
+  - `require/require_forward.go` - Forwarded require methods
+
+### Dependency Isolation Strategy
+- **internal/spew**: Internalized copy of go-spew for pretty-printing values
+- **internal/difflib**: Internalized copy of go-difflib for generating diffs
+- **assert/yaml**: Stub package that panics by default if YAML assertions are used
+- **enable/yaml**: Optional module that activates YAML support via init() when imported
+
+The "enable" pattern allows YAML functionality to be opt-in: import `_ "github.com/go-openapi/testify/v2/enable/yaml"` to activate YAML assertions without forcing a dependency on all users.
+
+## Development Commands
+
+### Running Tests
+```bash
+# Run all tests
+go test ./...
+
+# Run tests in a specific package
+go test ./assert
+go test ./require
+
+# Run a single test
+go test ./assert -run TestEqual
+
+# Run tests with verbose output
+go test -v ./...
+```
+
+### Code Generation
+When modifying assertion functions in `assert/assertions.go`, regenerate derived code:
+```bash
+# Generate all code
+go generate ./...
+
+# This runs the codegen tool which:
+# 1. Parses assert/assertions.go for TestingT functions
+# 2. Generates format variants (e.g., Equalf from Equal)
+# 3. Generates require variants (fatal versions)
+# 4. Generates forwarded assertion methods
+```
+
+The code generator looks for functions with signature `func(TestingT, ...) bool` in the assert package and creates corresponding variants.
+
+### Build and Verify
+```bash
+# Tidy dependencies
+go mod tidy
+
+# Build code generator
+cd _codegen && go build
+
+# Format code
+go fmt ./...
+```
+
+## Important Constraints
+
+### API Stability
+The following assertions are guaranteed stable (used by go-openapi/go-swagger):
+- Condition, Contains, Empty, Equal, EqualError, EqualValues, Error, ErrorContains, ErrorIs
+- Fail, FailNow, False, Greater, Implements, InDelta, IsType, JSONEq, Len
+- Nil, NoError, NotContains, NotEmpty, NotEqual, NotNil, NotPanics, NotZero
+- Panics, PanicsWithValue, Subset, True, YAMLEq, Zero
+
+Other APIs may change without notice as the project evolves.
+
+### Zero External Dependencies
+Do not add external dependencies to the main module. If new functionality requires a dependency:
+1. Consider internalizing it (copy into `internal/` with proper licensing)
+2. Or create an "enable" package that users import to activate the feature
+
+### YAML Support Pattern
+When using YAML assertions (YAMLEq, YAMLEqf):
+- Tests must import: `_ "github.com/go-openapi/testify/v2/enable/yaml"`
+- Without this import, YAML assertions will panic with helpful error message
+- This pattern keeps gopkg.in/yaml.v3 as an optional dependency
+
+## Module Information
+
+- Module path: `github.com/go-openapi/testify/v2`
+- Go version: 1.24.0
+- v2.0.0 is retracted (see go.mod)
+- License: Apache-2.0 (forked from MIT-licensed stretchr/testify)
+
+## Testing Philosophy
+
+Keep tests simple and focused. The assert package provides detailed failure messages automatically, so test code should be minimal and readable. Use `require` when a test cannot continue meaningfully after a failure, and `assert` when subsequent checks might provide additional context.
diff --git a/README.md b/README.md
index ebb60a69e..45b82ac53 100644
--- a/README.md
+++ b/README.md
@@ -73,6 +73,46 @@ However, at `go-openapi` we would like to address the well-known issues in `test
   testify-style mocks are thus not going to be supported anytime soon.
 * extra convoluted stuff in the like of `InDeltaSlice`
 
+## Generics adoption
+
+### Context from the original repository
+
+Several attempts have been made to introduce generics in the original stretchr/testify repository:
+
+* **github.com/stretchr/testify#1308** - Comprehensive refactor replacing `interface{}` with generic type parameters across assertions (Draft, v2.0.0 milestone)
+* **github.com/stretchr/testify#1805** - Proposal for generic `IsOfType[T]()` to avoid dummy value instantiation in type checks
+* **github.com/stretchr/testify#1685** - Iterator support (`iter.Seq`) for Contains/ElementsMatch assertions (Go 1.23+)
+* **github.com/stretchr/testify#1147** - General discussion about generics adoption (marked "Not Planned")
+
+### Challenges identified
+
+The original repository's exploration of generics revealed several design challenges:
+
+1. **Type inference limitations**: Go's type inference struggles with complex generic signatures, often requiring explicit type parameters that burden the API (e.g., `Contains[int, int](arr1, arr2)`)
+
+2. **Overly broad type constraints**: PR #1308's approach used constraints like `ConvertibleToFloat64` that accepted more types than intended, weakening type safety
+
+3. **Loss of flexibility**: Testify currently compares non-comparable types (slices, maps) via `reflect.DeepEqual`. Generic constraints would eliminate this capability, as Go generics require comparable or explicitly constrained types
+
+4. **Breaking changes**: Any comprehensive generics adoption requires a major version bump and Go 1.18+ minimum version
+
+5. **Inconsistent design patterns**: Different assertions would need different constraint strategies, making a uniform approach difficult
+
+### Approach in this fork
+
+This fork targets **go1.24** and can leverage generics without backward compatibility concerns.
+
+The approach will be **selective and pragmatic** rather than comprehensive:
+
+* **Targeted improvements** where generics provide clear value without compromising existing functionality
+* **Focus on eliminating anti-patterns** like dummy value instantiation in `IsType` (see #1805)
+* **Preserve reflection-based flexibility** for comparing complex types rather than forcing everything through generic constraints
+* **Careful constraint design** to ensure type safety without being overly restrictive or permissive
+
+The goal is to enhance type safety and developer experience where it matters most, while maintaining the flexibility that makes testify useful for real-world testing scenarios.
+
+**Status**: Design and exploration phase. Contributions and proposals welcome.
+
 ## Usage at go-openapi
 
 At this moment, we have identified the following usage in our tools. This API shall remain stable.
@@ -150,25 +190,46 @@ distributed with this fork, including internalized libraries.
 
 ## PRs from the original repo
 
+### Already merged or incorporated
+
 The following proposed contributions to the original repo have been merged or incorporated with
 some adaptations into this fork:
 
-* github.com/stretchr/testify#1513
-* github.com/stretchr/testify#1772
-* github.com/stretchr/testify#1797
-* github.com/stretchr/testify#1356
+* github.com/stretchr/testify#1513 - JSONEqBytes for byte slice JSON comparison
+* github.com/stretchr/testify#1772 - YAML library migration to maintained fork (go.yaml.in/yaml)
+* github.com/stretchr/testify#1797 - Codegen package consolidation and licensing
+* github.com/stretchr/testify#1356 - panic(nil) handling for Go 1.21+
+
+### Planned merges
+
+#### Critical safety fixes (high priority)
+
+* github.com/stretchr/testify#1825 - Fix panic when using EqualValues with uncomparable types
+* github.com/stretchr/testify#1818 - Fix panic on invalid regex in Regexp/NotRegexp assertions
+
+#### Leveraging internalized dependencies (go-spew, difflib)
+
+These improvements apply to the internalized and modernized copies of dependencies in this fork:
+
+* github.com/stretchr/testify#1829 - Fix time.Time rendering in diffs (internalized go-spew)
+* github.com/stretchr/testify#1822 - Deterministic map ordering in diffs (internalized go-spew)
+* github.com/stretchr/testify#1816 - Fix panic on unexported struct key in map (internalized go-spew - may need deeper fix)
+
+#### UX improvements
+
+* github.com/stretchr/testify#1223 - Display uint values in decimal instead of hex in diffs
+
+### Under consideration
 
-### Other noticeable contributions, not merged
+#### Colorized output
 
-These would probably need some rework/fix or adaptation, but the proposed idea is worthwhile, IMHO.
+Several PRs propose colorized terminal output with different approaches and dependencies.
+If implemented, this would be provided as an optional `enable/color` module:
 
-* github.com/stretchr/testify#1460 (ci)
-* github.com/stretchr/testify#1467 (colorized output)
-* github.com/stretchr/testify#1480 (colorized output)
-* github.com/stretchr/testify/pull#1232 (colorized output)
-* github.com/stretchr/testify#994 (colorized output)
-* github.com/stretchr/testify#1495 (bug fix)
-* github.com/stretchr/testify#1223 (layout bug fix)
+* github.com/stretchr/testify#1467 - Colorized output with terminal detection (most mature implementation)
+* github.com/stretchr/testify#1480 - Colorized diffs via TESTIFY_COLORED_DIFF env var
+* github.com/stretchr/testify#1232 - Colorized output for expected/actual/errors
+* github.com/stretchr/testify#994 - Colorize expected vs actual values
 
 ## Contributing
 
diff --git a/internal/difflib/LICENSE b/internal/difflib/LICENSE
index 485be13c6..261eeb9e9 100644
--- a/internal/difflib/LICENSE
+++ b/internal/difflib/LICENSE
@@ -1,27 +1,201 @@
-Copyright (c) 2013, Patrick Mezard
-All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
-    Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
-    Redistributions in binary form must reproduce the above copyright
-notice, this list of conditions and the following disclaimer in the
-documentation and/or other materials provided with the distribution.
-    The names of its contributors may not be used to endorse or promote
-products derived from this software without specific prior written
-permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
-IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
-TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
-PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
-TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
-PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
-LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
-NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
-SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
\ No newline at end of file
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+      "Contribution" shall mean any work of authorship, including
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+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
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+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
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+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
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+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
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+          of the NOTICE file are for informational purposes only and
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+
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+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
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diff --git a/internal/difflib/NOTICE b/internal/difflib/NOTICE
new file mode 100644
index 000000000..f2f4181e3
--- /dev/null
+++ b/internal/difflib/NOTICE
@@ -0,0 +1,49 @@
+Copyright 2025 go-swagger maintainers
+
+// SPDX-FileCopyrightText: Copyright 2025 go-swagger maintainers
+// SPDX-License-Identifier: Apache-2.0
+
+This software library, github.com/go-openapi/testify, includes software developed
+by the go-swagger and go-openapi maintainers ("go-swagger maintainers").
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this software except in compliance with the License.
+You may obtain a copy of the License at
+
+This software is copied from, derived from, and inspired mainly by github.com/pmezard/go-difflib.
+It ships with copies of other software which license terms are recalled below.
+
+
+github.com/pmezard/go-difflib
+===========================
+
+// SPDX-FileCopyrightText: Copyright (c) 2013, Patrick Mezard
+// SPDX-License-Identifier: BSD-3-Clause
+
+Copyright (c) 2013, Patrick Mezard
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+    Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+    Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in the
+documentation and/or other materials provided with the distribution.
+    The names of its contributors may not be used to endorse or promote
+products derived from this software without specific prior written
+permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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+TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/internal/difflib/README.md b/internal/difflib/README.md
new file mode 100644
index 000000000..ddc57fb36
--- /dev/null
+++ b/internal/difflib/README.md
@@ -0,0 +1,99 @@
+# internal/difflib
+
+This is an internalized and modernized copy of [github.com/pmezard/go-difflib](https://github.com/pmezard/go-difflib), a partial port of Python's difflib module for generating textual diffs.
+
+## Original Source
+
+**Source repository:** github.com/pmezard/go-difflib
+**Original license:** BSD 3-Clause License (see [LICENSE](./LICENSE))
+**Copyright:** 2013 Patrick Mezard
+**Maintenance status:** ⚠️ No longer maintained (archived by author)
+
+go-difflib provides tools to compare sequences of strings and generate textual diffs in unified or context format. It implements Python's `SequenceMatcher` class and `unified_diff()`/`context_diff()` functions.
+
+## Why Internalized
+
+This fork of testify maintains **zero external dependencies** for the core assertion packages. By internalizing go-difflib, we:
+
+1. Eliminate the external dependency on an **unmaintained package** (last updated 2014)
+2. Gain full control to apply modernizations aligned with our go1.24 target
+3. Can apply targeted fixes and optimizations specific to testify's use cases
+
+## Modernizations Applied
+
+This internalized copy has been significantly modernized and refactored from the original go-difflib codebase:
+
+### Go Language Features (Go 1.21+)
+
+- **Built-in functions:** Removed custom `min()` and `max()` functions in favor of Go 1.21+ built-ins
+- **Modern operators:** Used `--` instead of `-= 1` for decrement operations
+- **Efficient conversions:** Used `strconv.Itoa()` instead of `fmt.Sprintf("%d", ...)` for integer-to-string conversion
+- **Buffer handling:** Used `bytes.Buffer.String()` instead of `string(bytes.Buffer.Bytes())`
+- **Modern initialization:** Used `new(bytes.Buffer)` instead of `&bytes.Buffer{}`
+
+### Code Organization & Complexity Reduction
+
+- **Function extraction:** Refactored complex functions by extracting helper functions:
+  - `writeGroup()` - Handles writing diff groups
+  - `writeEqual()` - Writes unchanged lines
+  - `writeReplaceOrDelete()` - Writes deleted/replaced lines (prefix `-`)
+  - `writeReplaceOrInsert()` - Writes inserted/replaced lines (prefix `+`)
+- **Method reorganization:** Reordered methods for better logical flow (public methods first, then helpers)
+- **Named constants:** Added named constants for magic numbers (e.g., `hundred = 100`, `maxDisplayElements = 200`)
+
+### Code Quality
+
+- **Godoc compliance:** Updated all function comments to start with the function name for proper godoc generation
+  - `// Set two sequences` → `// SetSeqs sets two sequences`
+  - `// Return list of triples` → `// GetMatchingBlocks return the list of triples`
+- **Linting compliance:** Removed blank identifiers in range loops where value is unused
+  - `for s, _ := range` → `for s := range`
+- **Modern control flow:** Replaced if-else chains with switch statements for better readability
+- **Simplified logic:** Improved boolean expressions using De Morgan's laws
+  - `!(len(group) == 1 && group[0].Tag == 'e')` → `(len(group) != 1 || group[0].Tag != 'e')`
+- **Struct literals:** Simplified composite literals where types are inferred
+  - `OpCode{'e', 0, 1, 0, 1}` instead of `OpCode{Tag: 'e', I1: 0, I2: 1, J1: 0, J2: 1}`
+
+### Documentation
+
+- **Comment punctuation:** Standardized comment formatting and added proper punctuation
+- **Code clarity:** Added inline comments for switch cases explaining tag meanings (`'r'`, `'d'`, `'i'`, `'e'`)
+
+## API Compatibility
+
+The internalized copy maintains full API compatibility with the original go-difflib while incorporating the modernizations above. All public functions and types work identically to the upstream version.
+
+Key exports:
+- `SequenceMatcher` - Compares sequences of strings using the Ratcliff-Obershelp algorithm
+- `UnifiedDiff` / `WriteUnifiedDiff()` / `GetUnifiedDiffString()` - Generate unified diff format
+- `ContextDiff` / `WriteContextDiff()` / `GetContextDiffString()` - Generate context diff format
+- `SplitLines()` - Split strings on newlines while preserving them
+
+## Use in Testify
+
+This package is used by testify's assertion functions to generate human-readable diffs when assertions fail, particularly for comparing strings, slices, and complex data structures.
+
+The diff output helps developers quickly identify what changed between expected and actual values during test failures.
+
+## Future Enhancements
+
+As an internalized dependency, this copy can receive targeted improvements:
+
+- **Potential:** Performance optimizations for large diffs
+- **Potential:** Enhanced diff algorithms for specific data types
+- **Potential:** Colorized output support (if implemented as `enable/color` module)
+
+These enhancements would be difficult to incorporate if difflib remained an external, unmaintained dependency.
+
+## Maintenance
+
+This internalized copy is maintained as part of github.com/go-openapi/testify/v2 and follows the same Go version requirements (currently go1.24). It does not track upstream go-difflib releases, as the original repository is no longer maintained and this copy has diverged through modernization and refactoring.
+
+For issues or improvements specific to this internalized version, please file issues at:
+https://github.com/go-openapi/testify/issues
+
+## License
+
+This code retains its original BSD 3-Clause License. See [LICENSE](./LICENSE) for the full license text.
+
+The original copyright and license terms are preserved in accordance with the BSD License requirements.
diff --git a/internal/difflib/difflib.go b/internal/difflib/difflib.go
index cdcf1e9ee..8642002d4 100644
--- a/internal/difflib/difflib.go
+++ b/internal/difflib/difflib.go
@@ -1,21 +1,6 @@
-// Package difflib is a partial port of Python difflib module.
-//
-// It provides tools to compare sequences of strings and generate textual diffs.
-//
-// The following class and functions have been ported:
-//
-// - SequenceMatcher
-//
-// - unified_diff
-//
-// Getting unified diffs was the main goal of the port. Keep in mind this code
-// is mostly suitable to output text differences in a human friendly way, there
-// are no guarantees generated diffs are consumable by patch(1).
-//
-// This package was adopted from [github.com/pmezard/go-difflib] which
-// is no longer maintained.
-//
-// [github.com/pmezard/go-difflib]: https://github.com/pmezard/go-difflib
+// SPDX-FileCopyrightText: Copyright 2025 go-swagger maintainers
+// SPDX-License-Identifier: Apache-2.0
+
 package difflib
 
 import (
diff --git a/internal/difflib/difflib_test.go b/internal/difflib/difflib_test.go
index 20b0fc36d..2a14b74bc 100644
--- a/internal/difflib/difflib_test.go
+++ b/internal/difflib/difflib_test.go
@@ -1,3 +1,6 @@
+// SPDX-FileCopyrightText: Copyright 2025 go-swagger maintainers
+// SPDX-License-Identifier: Apache-2.0
+
 package difflib
 
 import (
diff --git a/internal/difflib/doc.go b/internal/difflib/doc.go
new file mode 100644
index 000000000..c167103ce
--- /dev/null
+++ b/internal/difflib/doc.go
@@ -0,0 +1,22 @@
+// SPDX-FileCopyrightText: Copyright 2025 go-swagger maintainers
+// SPDX-License-Identifier: Apache-2.0
+
+// Package difflib is a partial port of Python difflib module.
+//
+// It provides tools to compare sequences of strings and generate textual diffs.
+//
+// The following class and functions have been ported:
+//
+// - SequenceMatcher
+//
+// - unified_diff
+//
+// Getting unified diffs was the main goal of the port. Keep in mind this code
+// is mostly suitable to output text differences in a human friendly way, there
+// are no guarantees generated diffs are consumable by patch(1).
+//
+// This package was adopted from [github.com/pmezard/go-difflib] which
+// is no longer maintained.
+//
+// [github.com/pmezard/go-difflib]: https://github.com/pmezard/go-difflib
+package difflib
diff --git a/internal/spew/README.md b/internal/spew/README.md
new file mode 100644
index 000000000..9b41ba7e6
--- /dev/null
+++ b/internal/spew/README.md
@@ -0,0 +1,74 @@
+# internal/spew
+
+This is an internalized and modernized copy of [github.com/davecgh/go-spew](https://github.com/davecgh/go-spew), a deep pretty printer for Go data structures.
+
+## Original Source
+
+**Source repository:** github.com/davecgh/go-spew
+**Original license:** ISC License (see [LICENSE](./LICENSE))
+**Copyright:** 2012-2016 Dave Collins
+
+go-spew implements a deep pretty printer for Go data structures to aid in debugging, providing features like pointer dereferencing, circular reference detection, custom Stringer/error interface handling, and hexdump-style byte array output.
+
+## Why Internalized
+
+This fork of testify maintains **zero external dependencies** for the core assertion packages. By internalizing go-spew, we eliminate the external dependency while gaining full control over the code to apply modernizations aligned with our go1.24 target.
+
+## Modernizations Applied
+
+This internalized copy has been modernized from the original go-spew codebase with the following changes:
+
+### Go Language Features (Go 1.18+)
+
+- **Type aliases:** Replaced `interface{}` with `any` throughout
+- **Modern build tags:** Updated from `// +build` to `//go:build` format
+- **Range iteration:** Used `for i := range n` instead of `for i := 0; i < n; i++`
+- **reflect.TypeFor:** Replaced `reflect.TypeOf(T(0))` with `reflect.TypeFor[T]()`
+- **Standard library improvements:** Used `strings.ReplaceAll()` instead of `strings.Replace(..., -1)`
+
+### Code Quality
+
+- **Linting compliance:** Added linting directives (`//nolint`) with explanations where appropriate
+- **Test improvements:** Added `t.Helper()` calls in test helper functions
+- **Modern idioms:** Used `slices.Contains()` instead of manual loops
+- **String building:** Used `strings.Builder` for efficient string concatenation
+- **Code organization:** Improved struct field ordering and switch statement structure with explicit `fallthrough` comments
+
+### Documentation
+
+- **Markdown formatting:** Updated documentation comments to use modern markdown headings (`#`) and list formats (`-`)
+- **Comment punctuation:** Standardized comment punctuation and formatting
+- **Clarity improvements:** Fixed typos and improved readability
+
+### File Organization
+
+- **Test data relocation:** Moved `testdata/` to `testsrc/` with proper documentation
+
+## Notable Functional Enhancements
+
+The internalized copy maintains API compatibility with the original while incorporating targeted improvements:
+
+- **Deterministic map sorting:** The `SpewKeys` configuration option enables sorted map key output for consistent diffs (relevant for testify's assertion output)
+- **time.Time rendering:** Enhanced handling of `time.Time` values in nested structures (applied from stretchr/testify#1829)
+
+## Future Enhancements
+
+As an internalized dependency, this copy can receive targeted fixes and improvements that benefit testify's use case:
+
+- **Planned:** Proper fix for panic on unexported struct keys in maps (stretchr/testify#1816)
+- **Planned:** Additional optimizations for deterministic diff generation (stretchr/testify#1822)
+
+These enhancements would be difficult to incorporate if go-spew remained an external dependency.
+
+## Maintenance
+
+This internalized copy is maintained as part of github.com/go-openapi/testify/v2 and follows the same Go version requirements (currently go1.24). It does not track upstream go-spew releases, as it has diverged through modernization.
+
+For issues or improvements specific to this internalized version, please file issues at:
+https://github.com/go-openapi/testify/issues
+
+## License
+
+This code retains its original ISC License. See [LICENSE](./LICENSE) for the full license text.
+
+The original copyright and license terms are preserved in accordance with the ISC License requirements.