Add target 'check-md5' to build_keyboard.mk

[mtei]

Description

The check-md5 target provides an easy way to check the md5 checksum of the generated binary. This target will generate the binary and then display its md5 checksum.

The build-for-compare target provides an easy way to check the md5 checksum of the generated binary. This target generates a binary without embedding the git version and qmk version, and then displays the md5 checksum for that binary.

You can easily see if there is any change in the generated binaries between the two versions, as in the example below.

$ git checkout 0.11.0
M	build_keyboard.mk
M	tmk_core/rules.mk
Note: checking out '0.11.0'.
HEAD is now at c66df1664 2020 November 28 Breaking Changes Update (#11053)

$ make clean
$ make helix:all:check-md5 | grep ^MD5
MD5 (.build/helix_rev2_default.hex) = 5c3606562c944bb4d18832e601b45d4a
MD5 (.build/helix_rev2_edvorakjp.hex) = 9e43d13d389d518ba7e99cd7337e28d6
MD5 (.build/helix_rev2_five_rows.hex) = 8bcb61c2fd5d237c2997f2fa007d4934
MD5 (.build/helix_rev2_five_rows_jis.hex) = b97cd818d52f73ca2d4e78c86d90a791
MD5 (.build/helix_rev2_froggy.hex) = c492172364188f4e2918b10bf0f3a0a6
MD5 (.build/helix_rev2_froggy_106.hex) = b0861fd735a8f81881a8c02730641a2b
MD5 (.build/helix_rev2_led_test.hex) = 5c97d982a5da5cfb3dacb28a8934b81d
MD5 (.build/helix_rev2_xulkal.hex) = 01f603dc46bcf9094d7e106831d8f5b1
MD5 (.build/helix_rev2_yshrsmz.hex) = 5a008bca2d0c5790a151c02834c529ba

$ git checkout 0.11.1
M	build_keyboard.mk
M	tmk_core/rules.mk
Previous HEAD position was c66df1664 2020 November 28 Breaking Changes Update (#11053)
HEAD is now at cc08e3082 nix-shell: add milc dependency (#11086)

$ make clean
$ make helix:all:check-md5 | grep ^MD5
MD5 (.build/helix_rev2_default.hex) = 5c3606562c944bb4d18832e601b45d4a
MD5 (.build/helix_rev2_edvorakjp.hex) = 9e43d13d389d518ba7e99cd7337e28d6
MD5 (.build/helix_rev2_five_rows.hex) = 8bcb61c2fd5d237c2997f2fa007d4934
MD5 (.build/helix_rev2_five_rows_jis.hex) = b97cd818d52f73ca2d4e78c86d90a791
MD5 (.build/helix_rev2_froggy.hex) = c492172364188f4e2918b10bf0f3a0a6
MD5 (.build/helix_rev2_froggy_106.hex) = b0861fd735a8f81881a8c02730641a2b
MD5 (.build/helix_rev2_led_test.hex) = 5c97d982a5da5cfb3dacb28a8934b81d
MD5 (.build/helix_rev2_xulkal.hex) = d848383adfd7463b138c6da179cf1436
MD5 (.build/helix_rev2_yshrsmz.hex) = 5a008bca2d0c5790a151c02834c529ba

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[skullydazed]

We talked on discord about this and there seems to be some consensus behind making builds reproducible (md5 comparable) by default. I started a branch to show what that might look like here:

https://github.com/qmk/qmk_firmware/compare/reproducable_builds

This way you wouldn't need a build-for-compare rule, and would only need to add the md5 target from this PR.

What do you think?

[mtei]

qmk/reproducable_builds branch is looks good. May I cherry-pick it?

If so, I can make the following changes.

diff --git a/build_keyboard.mk b/build_keyboard.mk
index d2a86fc34..41d34278e 100644
--- a/build_keyboard.mk
+++ b/build_keyboard.mk
@@ -369,13 +369,7 @@ endif
 build: elf cpfirmware
 check-size: build
 objs-size: build
-build-for-compare: SKIP_GIT = yes
-build-for-compare: SKIP_VERSION = yes
-build-for-compare: SKIP_DEBUG_INFO = yes
-build-for-compare: build check-md5
-#      $(info SKIP_GIT=$(SKIP_GIT))
-#      $(info SKIP_VERSION=$(SKIP_VERSION))
-#      $(info SKIP_DEBUG_INFO=$(SKIP_DEBUG_INFO))
+check-md5: build
 
 include show_options.mk
 include $(TMK_PATH)/rules.mk

[mtei]

And it seems that 'DEBUG_ENABLE' is sometimes set to 'no'.

% find keyboards layouts -name '*.mk' | xargs grep DEBUG_ENABLE
keyboards/nek_type_a/rules.mk:DEBUG_ENABLE = yes
keyboards/miniaxe/rules.mk:DEBUG_ENABLE = no
keyboards/vitamins_included/rules.mk:DEBUG_ENABLE        = no   # Enable more debug info
......
layouts/community/ergodox/dvorak_programmer/rules.mk:DEBUG_ENABLE = no
layouts/community/ergodox/berfarah/rules.mk:DEBUG_ENABLE       = no
layouts/community/ergodox/algernon/rules.mk:DEBUG_ENABLE = no

So it looks like I should make the following additional changes.

diff --git a/tmk_core/rules.mk b/tmk_core/rules.mk
index 979d64607..c374b0fa4 100644
--- a/tmk_core/rules.mk
+++ b/tmk_core/rules.mk
@@ -82,6 +82,10 @@ CSTANDARD = -std=gnu99
 ifdef SKIP_DEBUG_INFO
   undefine DEBUG_ENABLE
 endif
+ifneq ($(strip $(DEBUG_ENABLE)),yes)
+  undefine DEBUG_ENABLE
+endif
+
 ifdef DEBUG_ENABLE
   CFLAGS += -g$(DEBUG)
 endif

[skullydazed]

qmk/reproducable_builds branch is looks good. May I cherry-pick it?

Yes, feel free to.

And it seems that 'DEBUG_ENABLE' is sometimes set to 'no'.

I do not think we need to make this second change. Since this flag did not actually do anything before it's likely they included that setting out of caution rather than intent.