If you have config with an implicit bool like:
[trace2]
envvars
we'll segfault, as we unconditionally try to xstrdup() the value. We
should instead detect and complain, as a boolean value has no meaning
here. The same is true for every variable in tr2_sysenv_settings (and
this patch covers them all, as we check them in a loop).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This should have been part of 783a86c142 (config: mark unused callback
parameters, 2022-08-19), but was missed in that commit.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a new "const struct config_context *ctx" arg to config_fn_t to hold
additional information about the config iteration operation.
config_context has a "struct key_value_info kvi" member that holds
metadata about the config source being read (e.g. what kind of config
source it is, the filename, etc). In this series, we're only interested
in .kvi, so we could have just used "struct key_value_info" as an arg,
but config_context makes it possible to add/adjust members in the future
without changing the config_fn_t signature. We could also consider other
ways of organizing the args (e.g. moving the config name and value into
config_context or key_value_info), but in my experiments, the
incremental benefit doesn't justify the added complexity (e.g. a
config_fn_t will sometimes invoke another config_fn_t but with a
different config value).
In subsequent commits, the .kvi member will replace the global "struct
config_reader" in config.c, making config iteration a global-free
operation. It requires much more work for the machinery to provide
meaningful values of .kvi, so for now, merely change the signature and
call sites, pass NULL as a placeholder value, and don't rely on the arg
in any meaningful way.
Most of the changes are performed by
contrib/coccinelle/config_fn_ctx.pending.cocci, which, for every
config_fn_t:
- Modifies the signature to accept "const struct config_context *ctx"
- Passes "ctx" to any inner config_fn_t, if needed
- Adds UNUSED attributes to "ctx", if needed
Most config_fn_t instances are easily identified by seeing if they are
called by the various config functions. Most of the remaining ones are
manually named in the .cocci patch. Manual cleanups are still needed,
but the majority of it is trivial; it's either adjusting config_fn_t
that the .cocci patch didn't catch, or adding forward declarations of
"struct config_context ctx" to make the signatures make sense.
The non-trivial changes are in cases where we are invoking a config_fn_t
outside of config machinery, and we now need to decide what value of
"ctx" to pass. These cases are:
- trace2/tr2_cfg.c:tr2_cfg_set_fl()
This is indirectly called by git_config_set() so that the trace2
machinery can notice the new config values and update its settings
using the tr2 config parsing function, i.e. tr2_cfg_cb().
- builtin/checkout.c:checkout_main()
This calls git_xmerge_config() as a shorthand for parsing a CLI arg.
This might be worth refactoring away in the future, since
git_xmerge_config() can call git_default_config(), which can do much
more than just parsing.
Handle them by creating a KVI_INIT macro that initializes "struct
key_value_info" to a reasonable default, and use that to construct the
"ctx" arg.
Signed-off-by: Glen Choo <chooglen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Moving a few functions around allows us to make dir.h no longer need to
include cache.h. This commit is best viewed with:
git log -1 -p --color-moved
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Via trace2, Git can already log interesting config parameters (see the
trace2_cmd_list_config() function). However, this can grant an
incomplete picture because many config parameters also allow overrides
via environment variables.
To allow for more complete logs, we add a new trace2_cmd_list_env_vars()
function and supporting implementation, modeled after the pre-existing
config param logging implementation.
Signed-off-by: Josh Steadmon <steadmon@google.com>
Acked-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
trace2 can write files into a target directory. With heavy usage, this
directory can fill up with files, causing difficulty for
trace-processing systems.
This patch adds a config option (trace2.maxFiles) to set a maximum
number of files that trace2 will write to a target directory. The
following behavior is enabled when the maxFiles is set to a positive
integer:
When trace2 would write a file to a target directory, first check
whether or not the traces should be discarded. Traces should be
discarded if:
* there is a sentinel file declaring that there are too many files
* OR, the number of files exceeds trace2.maxFiles.
In the latter case, we create a sentinel file named git-trace2-discard
to speed up future checks.
The assumption is that a separate trace-processing system is dealing
with the generated traces; once it processes and removes the sentinel
file, it should be safe to generate new trace files again.
The default value for trace2.maxFiles is zero, which disables the file
count check.
The config can also be overridden with a new environment variable:
GIT_TRACE2_MAX_FILES.
Signed-off-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
For an environment variable that is supposed to be set by users, the
GIT_TR2* env vars are just too unclear, inconsistent, and ugly.
Most of the established GIT_* environment variables don't use
abbreviations, and in case of the few that do (GIT_DIR,
GIT_COMMON_DIR, GIT_DIFF_OPTS) it's quite obvious what the
abbreviations (DIR and OPTS) stand for. But what does TR stand for?
Track, traditional, trailer, transaction, transfer, transformation,
transition, translation, transplant, transport, traversal, tree,
trigger, truncate, trust, or ...?!
The trace2 facility, as the '2' suffix in its name suggests, is
supposed to eventually supercede Git's original trace facility. It's
reasonable to expect that the corresponding environment variables
follow suit, and after the original GIT_TRACE variables they are
called GIT_TRACE2; there is no such thing is 'GIT_TR'.
All trace2-specific config variables are, very sensibly, in the
'trace2' section, not in 'tr2'.
OTOH, we don't gain anything at all by omitting the last three
characters of "trace" from the names of these environment variables.
So let's rename all GIT_TR2* environment variables to GIT_TRACE2*,
before they make their way into a stable release.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach git to read the system and global config files for
default Trace2 settings. This allows system-wide Trace2 settings to
be installed and inherited to make it easier to manage a collection of
systems.
The original GIT_TR2* environment variables are loaded afterwards and
can be used to override the system settings.
Only the system and global config files are used. Repo and worktree
local config files are ignored. Likewise, the "-c" command line
arguments are also ignored. These limits are for performance reasons.
(1) For users not using Trace2, there should be minimal overhead to
detect that Trace2 is not enabled. In particular, Trace2 should not
allocate lots of otherwise unused data strucutres.
(2) For accurate performance measurements, Trace2 should be initialized
as early in the git process as possible, and before most of the normal
git process initialization (which involves discovering the .git directory
and reading a hierarchy of config files).
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
