Improve build and test experience for Make builds (#14883)

Summary:
Local Make builds silently reuse object files even when build parameters (DEBUG_LEVEL, sanitizers, ASSERT_STATUS_CHECKED, RTTI, etc.) change, since all object files share the same paths. This leads to confusing linker errors, sanitizer false negatives, ODR violations, and "phantom" bugs that are easy to miss -- a pitfall for humans and especially for AI agents driving builds non-interactively.

This change improves the Make experience on three fronts:

1. Build-parameter change detection in the Makefile. After flags are fully resolved, we hash the effective compile/link inputs (CC|CXX|CFLAGS|CXXFLAGS|LDFLAGS|EXEC_LDFLAGS) into a per-OBJ_DIR .build_signature stamp and compare against the previous build:
   - Default: stop with a clear error when parameters changed. This is optimized for the expert who might not intend a full rebuild, and for avoiding CI inefficiency.
   - AUTO_CLEAN=1: automatically run clean-rocks and proceed.
   - ALLOW_BUILD_PARAMETER_CHANGE=1: skip the check (e.g. intentionally mixing DEBUG_LEVEL=1 and DEBUG_LEVEL=2 objects).
The check is skipped for dry runs (-n) and for non-building / self-cleaning targets (clean*, format, check-*, tags, gen-pc, check-progress, watch-log, release, coverage, the asan_*/ubsan_* variants, etc.). make_config.mk is removed only by the top-level `clean` target, not by clean-rocks, so the auto-clean does not delete the make_config.mk already included by the running make. The signature is removed last in clean-rocks so an interrupted clean keeps change detection meaningful.

3. New build_tools/rockstest.sh and build_tools/rocksptest.sh helpers that build and run unit tests in one step. They set AUTO_CLEAN=1 and build with -j<NCORES> (computed like the Makefile). rocksptest.sh runs one or more binaries under the checked-in gtest-parallel (sharing one parallel worker pool); rockstest.sh runs a single binary directly for a small number of cases. Both reject a leading-option first argument; `rockstest.sh install` writes ~/bin/rockstest and ~/bin/rocksptest shims that defer to the in-tree scripts (with a friendly message when run outside a source root). This is a big win for AI-agent workflows: one command instead of a separate `make` then test-run invocation, removing the overhead of monitoring two long commands, while avoiding serial builds and serial test execution.

4. CLAUDE.md guidance updated to recommend AUTO_CLEAN=1 for manual make invocations and the rocks(p)test.sh helpers for running tests

Although there might be drive to consolidate around the BUCK build for internal use, I'll note that last I checked it was around ~20 minutes to run all the unit tests under buck and ~2 minutes under `make check`.

Bonus: the first revision of this had copyright/license mistakes, and this change corrects similar errors elsewhere, with CLAUDE.md advice updated.

Pull Request resolved: #14883

Test Plan:
Manual verification of the Makefile change detection:
- Confirmed the resolved-flags hash is deterministic across runs for the same goal, and differs between configs (e.g. default/shared vs static_lib, and with/without ASSERT_STATUS_CHECKED).
- Unchanged parameters: rebuild does not error.
- Changed parameters: errors by default; AUTO_CLEAN=1 runs clean-rocks and proceeds; ALLOW_BUILD_PARAMETER_CHANGE=1 bypasses the check.
- Dry runs (make -n) and exempt targets (e.g. `make check-progress`, list_all_tests, gen-pc) do not trip the check and leave the stamp untouched.
- Reproduced the ASSERT_STATUS_CHECKED=1 auto-clean path end to end and confirmed it no longer fails with "No rule to make target 'make_config.mk'"; verified `make clean` removes make_config.mk while `clean-rocks` does not, and that the signature is deleted as the final clean-rocks step.

Manual verification of the helper scripts:
- shellcheck-clean and `bash -n` pass for both scripts.
- Usage/guard behavior: missing argument and leading-option first argument are rejected with a clear message.
- `rockstest.sh install` (validated against a temp HOME) generates both shims; running a shim outside a source root prints "(Not in a rocksdb source root directory?)" and exits non-zero.
- rocksptest.sh argument splitting verified for single binary, multiple binaries, and binaries followed by gtest-parallel/test args.
- .gitignore patterns verified with `git check-ignore` for .build_signature (root and jl/jls) and build_tools/__pycache__/.

Reviewed By: xingbowang

Differential Revision: D109713512

Pulled By: pdillinger

fbshipit-source-id: a801d29afa91f53a2dce717db9fe5e5d485cc154

Author: pdillinger

.gitignore

@@ -1,5 +1,7 @@
 make_config.mk
 rocksdb.pc
+.build_signature
+build_tools/__pycache__/
 
 *.a
 *.arc

CLAUDE.md

@@ -244,26 +244,15 @@ from an implementation detail instead of an explicit option.
     /usr/local/bin/python3 buckifier/buckify_rocksdb.py to update it
 * For -j in make command, use the number of CPU cores to decide it.
 
-### When to run `make clean` (avoid mixing build modes)
+### Avoiding mixed build modes with Make (use `AUTO_CLEAN=1`)
 
-The Makefile does **not** track build mode, so object files from a prior
-build are silently reused even when compiled with different flags, leading
-to confusing linker errors, sanitizer false negatives, ODR violations, or
-"phantom" bugs.
-
-Run `make clean` before switching any of these:
-* **`ASSERT_STATUS_CHECKED=1` ↔ unset** — changes the `Status` class layout (ABI break).
-* **Sanitizer builds** — toggling any of `COMPILE_WITH_ASAN=1`,
-    `COMPILE_WITH_UBSAN=1`, `COMPILE_WITH_TSAN=1` on/off.
-* `DEBUG_LEVEL=0` (release) ↔ `DEBUG_LEVEL=1` (debug, default for `make dbg`).
-* Different compilers, `OPT` levels, or other flags affecting codegen/ABI.
-
-**Notable exception:** `DEBUG_LEVEL=2` can be safely mixed with
-`DEBUG_LEVEL=1` — rebuild a subset of files with `DEBUG_LEVEL=2` to get
-extra/more accurate runtime checks for those files without a full clean.
-
-When in doubt, `make clean` is cheap insurance compared to chasing a
-phantom bug.
+Object files are written to the same paths regardless of build flags, so
+reusing objects from a prior build with different flags causes confusing
+linker errors, etc. This problem is essentially avoidable by ALWAYS using
+`AUTO_CLEAN=1 make -j<n> <something>` for manual make invocations. This
+will automatically clean object files if the build parameters/flavor have
+changed. The `build_tools/rockstest.sh` / `rocksptest.sh` helpers described
+below set `AUTO_CLEAN=1` for you.
 
 ### Source checks
 * Run `make check-sources` before committing. This catches non-ASCII
@@ -272,6 +261,22 @@ phantom bug.
     smart quotes, etc.) in comments or strings -- use ASCII equivalents
     (`--` instead of em dash, `'` instead of smart quote, etc.).
 
+### License headers
+* Every new source file needs a license header. For a file that does **not**
+    carry an outside/third-party copyright, use the standard Meta dual-licensed
+    header (the dual-license designation is required -- a bare
+    "All Rights Reserved" copyright is not an acceptable open-source header):
+    ```
+    //  Copyright (c) Meta Platforms, Inc. and affiliates.
+    //  This source code is licensed under both the GPLv2 (found in the
+    //  COPYING file in the root directory) and Apache 2.0 License
+    //  (found in the LICENSE.Apache file in the root directory).
+    ```
+    Use a `#` comment prefix instead of `//` for shell, Python, and Makefile
+    fragments.
+* Files derived from an external source (e.g. LevelDB) keep their original
+    upstream copyright line in addition to the header above.
+
 ### RTTI and dynamic_cast
 * Production code and `db_stress` must build in **release mode
     (`-fno-rtti`)**. Do not use `dynamic_cast` anywhere except unit tests.
@@ -309,13 +314,22 @@ rather than relying on libstdc++ transitive includes.
 * Don't use sleep to wait for certain events to happen. This will cause test to
     be flaky. Instead, use sync point to synchronize thread progress.
 * Cap unit test execution with 60 seconds timeout.
-* When there are multiple unit tests need to be executed, try to use
-    gtest_parallel.py if available. E.g.
-    python3 ${GTEST_PARALLEL}/gtest_parallel.py ./table_test
-* After writing a test, stress-test for flakiness:
+* To build and run unit tests locally, prefer these helper scripts:
+    * `build_tools/rocksptest.sh <test_binary> [more_binaries...] [args...]`
+        builds the binary(ies) with parallel make and `AUTO_CLEAN=1` and runs
+        them under gtest-parallel, sharding the test cases across CPUs. Prefer
+        this whenever running more than a couple of test cases, e.g.
+        `build_tools/rocksptest.sh table_test` or
+        `build_tools/rocksptest.sh db_test env_test --gtest_filter=*Foo*`.
+    * `build_tools/rockstest.sh <test_binary> [args...]` builds with parallel
+        make and `AUTO_CLEAN=1` and runs the binary directly (serially).
+        Use it only for a very small number of test cases, e.g.
+        `build_tools/rockstest.sh db_test --gtest_filter=*MixedSlowdown*`.
+* After writing a test, stress-test for flakiness (AUTO_CLEAN handles the
+    rebuild needed by the `COERCE_CONTEXT_SWITCH=1` flag change):
     ```bash
-    COERCE_CONTEXT_SWITCH=1 make {test_binary}
-    ./{test_binary} --gtest_filter="*YourTestName*" --gtest_repeat=5
+    COERCE_CONTEXT_SWITCH=1 build_tools/rockstest.sh {test_binary} -r100 \
+        --gtest_filter="*YourTestName*"
     ```
 * For CI-style flaky tests that do not reproduce with `gtest_parallel.py`,
     `--gtest_repeat`, or normal coerce-mode runs, inspect
@@ -372,20 +386,21 @@ rather than relying on libstdc++ transitive includes.
 * Blog post authors must be defined in `docs/_data/authors.yml` to be displayed
 
 ### Final verification of the change
-* Execute make clean to clean all of the changes.
-* Execute make check to build all of the changes and execute all of the tests.
-    Note that executing all of the tests could take multiple minutes.
-* Run `ASSERT_STATUS_CHECKED=1 make check` to verify all Status objects are
-    properly checked. This catches missing error handling that can lead to
-    silent data corruption.
+* Execute `AUTO_CLEAN=1 make check` to build all of the changes and execute all
+    of the tests. `AUTO_CLEAN=1` ensures a clean rebuild if your previous build
+    used different parameters. Note that executing all of the tests could take
+    multiple minutes.
+* Run `AUTO_CLEAN=1 ASSERT_STATUS_CHECKED=1 make check` to verify all Status
+    objects are properly checked. This catches missing error handling that can
+    lead to silent data corruption.
 
 ### Monitoring make check progress
 * Use `make check-progress` to get machine-parseable JSON progress while
     `make check` is running. This is useful for Claude Code to monitor long
     builds without timeout issues.
 * Run `make check` in background, then poll progress:
     ```bash
-    make check &
+    AUTO_CLEAN=1 make check &
     # Poll periodically:
     make check-progress
     ```
@@ -410,9 +425,10 @@ rather than relying on libstdc++ transitive includes.
 
 ### Executing benchmark using db_bench
 * Since the goal is to measure performance, we need to build a release binary
-    using `make clean && DEBUG_LEVEL=0 make db_bench`. If there is an engine
-    crash due to bug, we need to switch back to debug build. Make sure to run
-    `make clean` before running `make dbg`.
+    using `AUTO_CLEAN=1 DEBUG_LEVEL=0 make db_bench`. If there is an engine
+    crash due to a bug, switch back to a debug build with
+    `AUTO_CLEAN=1 make dbg`; `AUTO_CLEAN=1` handles the release<->debug rebuild
+    automatically.
 
 ### Formatting code
 * After making change, use `make format-auto` to auto-apply formatting without

Makefile

@@ -288,7 +288,7 @@ endif
 endif
 
 export JAVAC_ARGS
-CLEAN_FILES += make_config.mk rocksdb.pc
+CLEAN_FILES += rocksdb.pc
 
 ifeq ($(V), 1)
 $(info $(shell uname -a))
@@ -1359,8 +1359,13 @@ rocksdb.h rocksdb.cc: build_tools/amalgamate.py Makefile $(LIB_SOURCES) unity.cc
 	build_tools/amalgamate.py -I. -i./include unity.cc -x include/rocksdb/c.h -H rocksdb.h -o rocksdb.cc
 
 clean: clean-ext-libraries-all clean-rocks clean-rocksjava
+# Removed here rather than in clean-rocks (via CLEAN_FILES) so the build-parameter
+# auto-clean, which runs clean-rocks, doesn't delete the make_config.mk already
+# included by the in-progress make.
+	@rm -f make_config.mk
 
 clean-not-downloaded: clean-ext-libraries-bin clean-rocks clean-not-downloaded-rocksjava
+	@rm -f make_config.mk
 
 clean-rocks:
 # Not practical to exactly match all versions/variants in naming (e.g. debug or not)
@@ -1375,6 +1380,11 @@ clean-rocks:
 	else \
 		$(FIND) . -name "*.[oda]" -exec rm -f {} \; ; \
 	fi
+# Remove the build signature(s) LAST. Done after the object files are gone so
+# that a Ctrl+C partway through clean leaves the old signature in place: it
+# still matches the leftover objects, so a later build with different
+# parameters is still detected (signature usefulness is preserved).
+	@rm -f $(BUILD_SIG_FILE) jl/.build_signature jls/.build_signature
 
 clean-rocksjava: clean-rocks
 	rm -rf jl jls
@@ -2408,6 +2418,101 @@ ifeq ($(PLATFORM), OS_OPENBSD)
 endif
 export SHA256_CMD
 
+# ----------------------------------------------------------------------------
+# Build parameter change detection
+# ----------------------------------------------------------------------------
+# RocksDB writes object files to the same $(OBJ_DIR) paths regardless of
+# DEBUG_LEVEL, sanitizers (ASAN/TSAN/UBSAN), ASSERT_STATUS_CHECKED, RTTI, LTO,
+# COERCE_CONTEXT_SWITCH, etc.  Most of those are applied in this Makefile after
+# `include make_config.mk` and are therefore NOT reflected in make_config.mk,
+# so switching them and rebuilding silently mixes incompatible object files.
+# To guard against that, we hash the fully-resolved compile/link parameters
+# (which already embed make_config.mk via PLATFORM_*) and compare against the
+# value recorded from the previous build.  On mismatch the build stops so the
+# user can `make clean`.  Knobs:
+#   AUTO_CLEAN=1
+#     run `make clean-rocks` automatically on mismatch
+#   ALLOW_BUILD_PARAMETER_CHANGE=1
+#     skip the check entirely (e.g. intentionally mixing DEBUG_LEVEL=1 and
+#     DEBUG_LEVEL=2)
+# The signature is stored per-$(OBJ_DIR), so Java (jl/jls) builds are tracked
+# independently from the default build.
+BUILD_SIG_FILE := $(OBJ_DIR)/.build_signature
+# NOTE: deliberately NOT added to CLEAN_FILES. The signature is removed as the
+# very last step of clean-rocks so that an interrupted clean keeps it (see
+# clean-rocks), preserving change detection across a Ctrl+C'd clean.
+
+# Goals that do not compile object files into the tree (pure utilities,
+# informational, source/config checks): the change check is irrelevant for them.
+BUILD_SIG_NONBUILD_GOALS := \
+	clean clean-rocks clean-not-downloaded clean-rocksjava \
+	clean-not-downloaded-rocksjava clean-ext-libraries-all \
+	clean-ext-libraries-bin \
+	format format-auto check-format check-buck-targets check-headers \
+	check-sources check-workflow-yaml check-progress clang-tidy \
+	tags tags0 package jclean checkout_folly \
+	watch-log dump-log suggest-slow-tests list_all_tests gen-pc \
+	gen_parallel_tests check-c-api-gen \
+	setup-hooks install-hooks uninstall-hooks uninstall db_crashtest_tests
+# Goals that clean before building (depend on or invoke `clean`): they manage
+# their own freshness, so the check must not block them (it would error before
+# their built-in clean runs).
+BUILD_SIG_NONBUILD_GOALS += \
+	release coverage build_size analyze analyze_incremental \
+	asan_check asan_crash_test asan_crash_test_with_atomic_flush \
+	asan_crash_test_with_txn asan_crash_test_with_best_efforts_recovery \
+	whitebox_asan_crash_test blackbox_asan_crash_test \
+	ubsan_check ubsan_crash_test ubsan_crash_test_with_atomic_flush \
+	ubsan_crash_test_with_txn ubsan_crash_test_with_best_efforts_recovery \
+	whitebox_ubsan_crash_test blackbox_ubsan_crash_test
+
+# Goals that explicitly clean; never trip the check when one is requested.
+BUILD_SIG_CLEAN_GOALS := \
+	clean clean-rocks clean-not-downloaded clean-rocksjava \
+	clean-not-downloaded-rocksjava clean-ext-libraries-all \
+	clean-ext-libraries-bin
+
+BUILD_SIG_GOALS := $(if $(MAKECMDGOALS),$(MAKECMDGOALS),all)
+BUILD_SIG_DO_BUILD := $(filter-out $(BUILD_SIG_NONBUILD_GOALS),$(BUILD_SIG_GOALS))
+BUILD_SIG_CLEANING := $(filter $(BUILD_SIG_CLEAN_GOALS),$(MAKECMDGOALS))
+# Dry runs (-n/--just-print) must not write the stamp, clean, or error; the
+# parse-time $(shell) below would otherwise run even under -n. Note that
+# actual options are canonicalized and shorted as possible such that all
+# short options are in the first word of MAKEFLAGS.
+BUILD_SIG_DRYRUN := $(findstring n,$(firstword -$(MAKEFLAGS)))
+
+# Only enforce at the top level. Sub-makes (e.g. `check` invokes
+# $(MAKE) gen_parallel_tests / check-c-api-gen / check_0) inherit the parent's
+# build flags, so the top-level check already covers them; re-checking inside a
+# sub-make only causes spurious failures.
+ifneq ($(ALLOW_BUILD_PARAMETER_CHANGE),1)
+ifeq ($(MAKELEVEL),0)
+ifeq ($(BUILD_SIG_DRYRUN),)
+ifeq ($(BUILD_SIG_CLEANING),)
+ifneq ($(BUILD_SIG_DO_BUILD),)
+  BUILD_SIG := $(shell printf '%s' '$(CC)|$(CXX)|$(CFLAGS)|$(CXXFLAGS)|$(LDFLAGS)|$(EXEC_LDFLAGS)' | $(SHA256_CMD) | cut -d ' ' -f 1)
+  BUILD_SIG_OLD := $(shell cat $(BUILD_SIG_FILE) 2>/dev/null)
+  ifneq ($(BUILD_SIG_OLD),)
+  ifneq ($(BUILD_SIG_OLD),$(BUILD_SIG))
+  ifeq ($(AUTO_CLEAN),1)
+    $(info *** Build parameters changed since last build (OBJ_DIR=$(OBJ_DIR)); running 'make clean-rocks' because AUTO_CLEAN=1)
+    BUILD_SIG_CLEAN_OUTPUT := $(shell $(MAKE) clean-rocks 1>&2)
+    ifneq ($(.SHELLSTATUS),0)
+      $(error AUTO_CLEAN: 'make clean-rocks' failed (exit $(.SHELLSTATUS)); not building against a partially-cleaned tree)
+    endif
+  else
+    $(error Build parameters changed since the last build (OBJ_DIR=$(OBJ_DIR)). Existing object files are stale and must be removed. Run 'make clean', or set AUTO_CLEAN=1 to clean automatically, or ALLOW_BUILD_PARAMETER_CHANGE=1 to build anyway)
+  endif
+  endif
+  endif
+  # Record the current signature for the next build.
+  BUILD_SIG_WRITE := $(shell mkdir -p $(OBJ_DIR) 2>/dev/null; printf '%s\n' '$(BUILD_SIG)' > $(BUILD_SIG_FILE))
+endif
+endif
+endif
+endif
+endif
+
 zlib-$(ZLIB_VER).tar.gz:
 	curl --fail --output zlib-$(ZLIB_VER).tar.gz --location ${ZLIB_DOWNLOAD_BASE}/zlib-$(ZLIB_VER).tar.gz
 	ZLIB_SHA256_ACTUAL=`$(SHA256_CMD) zlib-$(ZLIB_VER).tar.gz | cut -d ' ' -f 1`; \

build_tools/check-public-header.sh

@@ -1,5 +1,8 @@
 #!/usr/bin/env bash
-# Copyright (c) Meta Platforms, Inc. and affiliates. All Rights Reserved.
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# This source code is licensed under both the GPLv2 (found in the
+# COPYING file in the root directory) and Apache 2.0 License
+# (found in the LICENSE.Apache file in the root directory).
 #
 # Check for some simple mistakes in public headers (on the command line)
 # that should prevent commit or push

build_tools/gtest-parallel

@@ -0,0 +1,18 @@
+#!/usr/bin/env python3
+# Copyright 2017 Google Inc. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import gtest_parallel
+import sys
+
+sys.exit(gtest_parallel.main())