git/config.mak.dev, branch v2.29.2

repository: enable SHA-256 support by default

2020-07-30T16:16:49Z

Now that we have a complete SHA-256 implementation in Git, let's enable it so people can use it. Remove the ENABLE_SHA256 define constant everywhere it's used. Add tests for initializing a repository with SHA-256. Signed-off-by: brian m. carlson Reviewed-by: Eric Sunshine Signed-off-by: Junio C Hamano

Merge branch 'bc/sha-256-part-1-of-4'

2020-03-27T00:11:20Z

SHA-256 transition continues. * bc/sha-256-part-1-of-4: (22 commits) fast-import: add options for rewriting submodules fast-import: add a generic function to iterate over marks fast-import: make find_marks work on any mark set fast-import: add helper function for inserting mark object entries fast-import: permit reading multiple marks files commit: use expected signature header for SHA-256 worktree: allow repository version 1 init-db: move writing repo version into a function builtin/init-db: add environment variable for new repo hash builtin/init-db: allow specifying hash algorithm on command line setup: allow check_repository_format to read repository format t/helper: make repository tests hash independent t/helper: initialize repository if necessary t/helper/test-dump-split-index: initialize git repository t6300: make hash algorithm independent t6300: abstract away SHA-1-specific constants t: use hash-specific lookup tables to define test constants repository: require a build flag to use SHA-256 hex: add functions to parse hex object IDs in any algorithm hex: introduce parsing variants taking hash algorithms ...

config.mak.dev: re-enable -Wformat-zero-length

2020-02-28T16:39:45Z

We recently triggered some -Wformat-zero-length warnings in the code, but no developers noticed because we suppress that warning in builds with the DEVELOPER=1 Makefile knob set. But we _don't_ suppress them in a non-developer build (and they're part of -Wall). So even though non-developers probably aren't using -Werror, they see the annoying warnings when they build. We've had back and forth discussion over the years on whether this warning is useful or not. In most cases we've seen, it's not true that the call is a mistake, since we're using its side effects (like adding a newline status_printf_ln()) or writing an empty string to a destination which is handled by the function (as in write_file()). And so we end up working around it in the source by passing ("%s", ""). There's more discussion in the subthread starting at: https://lore.kernel.org/git/xmqqtwaod7ly.fsf@gitster.mtv.corp.google.com/ The short of it is that we probably can't just disable the warning for everybody because of portability issues. And ignoring it for developers puts us in the situation we're in now, where non-dev builds are annoyed. Since the workaround is both rarely needed and fairly straight-forward, let's just commit to doing it as necessary, and re-enable the warning. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

repository: require a build flag to use SHA-256

2020-02-24T17:33:21Z

At this point, SHA-256 support is experimental and some behavior may change. To avoid surprising unsuspecting users, require a build flag, ENABLE_SHA256, to allow use of a non-SHA-1 algorithm. Enable this flag by default when the DEVELOPER make flag is set so that contributors can test this case adequately. Signed-off-by: brian m. carlson Signed-off-by: Junio C Hamano

Makefile: allow for combining DEVELOPER=1 and CFLAGS="..."

2019-02-24T15:35:07Z

Ever since the DEVELOPER=1 facility introduced there's been no way to have custom CFLAGS (e.g. CFLAGS="-O0 -g -ggdb3") while still benefiting from the set of warnings and assertions DEVELOPER=1 enables. This is because the semantics of variables in the Makefile are such that the user setting CFLAGS overrides anything we set, including what we're doing in config.mak.dev[1]. So let's introduce a "DEVELOPER_CFLAGS" variable in config.mak.dev and add it to ALL_CFLAGS. Before this the ALL_CFLAGS variable would (basically, there's some nuance we won't go into) be set to: $(CPPFLAGS) [$(CFLAGS) *or* $(CFLAGS) in config.mak.dev] $(BASIC_CFLAGS) $(EXTRA_CPPFLAGS) But will now be: $(DEVELOPER_CFLAGS) $(CPPFLAGS) $(CFLAGS) $(BASIC_CFLAGS) $(EXTRA_CPPFLAGS) The reason for putting DEVELOPER_CFLAGS first is to allow for selectively overriding something DEVELOPER=1 brings in. On both GCC and Clang later settings override earlier ones. E.g. "-Wextra -Wno-extra" will enable no "extra" warnings, but not if those two arguments are reversed. Examples of things that weren't possible before, but are now: # Use -O0 instead of -O2 for less painful debuggng DEVELOPER=1 CFLAGS="-O0 -g" # DEVELOPER=1 plus -Wextra, but disable some of the warnings DEVELOPER=1 DEVOPTS="no-error extra-all" CFLAGS="-O0 -g -Wno-unused-parameter" The reason for the patches leading up to this one re-arranged the various *FLAGS assignments and includes is just for readability. The Makefile supports assignments out of order, e.g.: $ cat Makefile X = $(A) $(B) $(C) A = A B = B include c.mak all: @echo $(X) $ cat c.mak C=C $ make A B C So we could have gotten away with the much smaller change of changing "CFLAGS" in config.mak.dev to "DEVELOPER_CFLAGS" and adding that to ALL_CFLAGS earlier in the Makefile "before" the config.mak.* includes. But I think it's more readable to use variables "after" they're included. 1. https://www.gnu.org/software/make/manual/html_node/Overriding.html Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Junio C Hamano

Merge branch 'jk/dev-build-format-security'

2019-01-18T21:49:55Z

Earlier we added "-Wformat-security" to developer builds, assuming that "-Wall" (which includes "-Wformat" which in turn is required to use "-Wformat-security") is always in effect. This is not true when config.mak.autogen is in use, unfortunately. This has been fixed by unconditionally adding "-Wall" to developer builds. * jk/dev-build-format-security: config.mak.dev: add -Wall, primarily for -Wformat, to help autoconf users

config.mak.dev: add -Wall, primarily for -Wformat, to help autoconf users

2019-01-07T17:02:08Z

801fa63a90 ("config.mak.dev: add -Wformat-security", 2018-09-08) added the "-Wformat-security" to the flags set in config.mak.dev. In the gcc man page this is documented as: If -Wformat is specified, also warn about uses of format functions that represent possible security problems. [...] The commit did however not add the "-Wformat" flag, but instead relied on the fact that "-Wall" is set in the Makefile by default and that "-Wformat" is part of "-Wall". Unfortunately, those who use config.mak.autogen generated with the autoconf to configure toolchain do *not* get "-Wall" in their CFLAGS and the added -Wformat-security had no effect. Worse yet, newer versions of gcc (gcc 8.2.1 in this particular case) warn about the lack of "-Wformat" and thus compilation fails only with this option set. We could fix it by adding "-Wformat", but in general we do want all checks included in "-Wall", so let's add it to config.mak.dev to cover more cases. Signed-off-by: Thomas Gummerer Helped-by: Jeff King Helped-by: Jonathan Nieder Signed-off-by: Junio C Hamano

Merge branch 'jk/unused-function'

2018-10-30T06:43:46Z

Developer support. * jk/unused-function: config.mak.dev: enable -Wunused-function

config.mak.dev: enable -Wunused-function

2018-10-19T01:24:11Z

We explicitly omitted -Wunused-function when we added -Wextra, but there is no need: the current code compiles cleanly with it. And it's worth having, since it can let you know when there are cascading effects from a cleanup (e.g., deleting one function lets you delete its static helpers). There are cases where we may need an unused function to exist, but we can handle these easily: - macro-generated code like commit-slab; there we have the MAYBE_UNUSED annotation to silence the compiler - conditional compilation, where we may or may not need a static helper. These generally fall into one of two categories: - the call should not be conditional, but rather the function body itself should be (and may just be a no-op on one side of the #if). That keeps the conditional pollution out of the main code. - call-chains of static helpers should all be in the same #if block, so they are all-or-nothing And if there's some case that doesn't cover, we still have MAYBE_UNUSED as a fallback. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

Merge branch 'jk/dev-build-format-security'

2018-09-24T17:30:49Z

Build tweak to help developers. * jk/dev-build-format-security: config.mak.dev: add -Wformat-security