Merge branch 'feature/remove_make_dependency_on_git' into 'master'

make: remove build system dependency on `git` using some hooks

See merge request idf/esp-idf!2211

docs/en/api-guides/build-system.rst

@@ -185,7 +185,7 @@ The following variables are set at the project level, but exported for use in th
 - ``CONFIG_*``: Each value in the project configuration has a corresponding variable available in make. All names begin with ``CONFIG_``.
 - ``CC``, ``LD``, ``AR``, ``OBJCOPY``: Full paths to each tool from the gcc xtensa cross-toolchain.
 - ``HOSTCC``, ``HOSTLD``, ``HOSTAR``: Full names of each tool from the host native toolchain.
-- ``IDF_VER``: Git version of ESP-IDF (produced by ``git describe``)
+- ``IDF_VER``: ESP-IDF version, retrieved from either ``$(IDF_PATH)/version.txt`` file (if present) else using git command ``git describe``. Recommended format here is single liner that specifies major IDF release version, e.g. ``v2.0`` for a tagged release or ``v2.0-275-g0efaa4f`` for an arbitrary commit. Application can make use of this by calling :cpp:func:`esp_get_idf_version`.
 
 If you modify any of these variables inside ``component.mk`` then this will not prevent other components from building but it may make your component hard to build and/or debug.
 
@@ -298,7 +298,7 @@ Preprocessor Definitions
 ESP-IDF build systems adds the following C preprocessor definitions on the command line:
 
 - ``ESP_PLATFORM`` — Can be used to detect that build happens within ESP-IDF.
-- ``IDF_VER`` — Defined to a git version string.  E.g. ``v2.0`` for a tagged release or ``v1.0-275-g0efaa4f`` for an arbitrary commit.
+- ``IDF_VER`` — ESP-IDF version, see `Preset Component Variables`_ for more details.
 
 Build Process Internals
 -----------------------

make/project.mk

@@ -227,7 +227,12 @@ endif
 	@echo $(ESPTOOLPY_WRITE_FLASH) $(ESPTOOL_ALL_FLASH_ARGS)
 
 
+# If we have `version.txt` then prefer that for extracting IDF version
+ifeq ("$(wildcard ${IDF_PATH}/version.txt)","")
 IDF_VER := $(shell cd ${IDF_PATH} && git describe --always --tags --dirty)
+else
+IDF_VER := `cat ${IDF_PATH}/version.txt`
+endif
 
 # Set default LDFLAGS
 EXTRA_LDFLAGS ?=
@@ -485,6 +490,8 @@ clean: app-clean bootloader-clean config-clean
 #
 # This only works for components inside IDF_PATH
 check-submodules:
+# Check if .gitmodules exists, otherwise skip submodule check, assuming flattened structure
+ifneq ("$(wildcard ${IDF_PATH}/.gitmodules)","")
 
 # Dump the git status for the whole working copy once, then grep it for each submodule. This saves a lot of time on Windows.
 GIT_STATUS := $(shell cd ${IDF_PATH} && git status --porcelain --ignore-submodules=dirty)
@@ -509,6 +516,7 @@ endef
 # filter/subst in expression ensures all submodule paths begin with $(IDF_PATH), and then strips that prefix
 # so the argument is suitable for use with 'git submodule' commands
 $(foreach submodule,$(subst $(IDF_PATH)/,,$(filter $(IDF_PATH)/%,$(COMPONENT_SUBMODULES))),$(eval $(call GenerateSubmoduleCheckTarget,$(submodule))))
+endif # End check for .gitmodules existence
 
 
 # PHONY target to list components in the build and their paths

tools/ci/test_build_system.sh

@@ -209,6 +209,23 @@ function run_tests()
     git checkout main/component.mk
     rm -rf extra_source_dir
 
+    print_status "Can build without git installed on system"
+    clean_build_dir
+    # Make provision for getting IDF version
+    echo "custom-version-x.y" > ${IDF_PATH}/version.txt
+    # Hide .gitmodules so that submodule check is avoided
+    [ -f ${IDF_PATH}/.gitmodules ] && mv ${IDF_PATH}/.gitmodules ${IDF_PATH}/.gitmodules_backup
+    # Overload `git` command
+    echo -e '#!/bin/bash\ntouch ${IDF_PATH}/git_invoked' > git
+    chmod +x git
+    OLD_PATH=$PATH
+    export PATH="$PWD:$PATH"
+    make
+    [ -f ${IDF_PATH}/git_invoked ] && rm ${IDF_PATH}/git_invoked && failure "git should not have been invoked in this case"
+    rm -f ${IDF_PATH}/version.txt git
+    [ -f ${IDF_PATH}/.gitmodules_backup ] && mv ${IDF_PATH}/.gitmodules_backup ${IDF_PATH}/.gitmodules
+    export PATH=$OLD_PATH
+
     print_status "All tests completed"
     if [ -n "${FAILURES}" ]; then
         echo "Some failures were detected:"