[PATCH v4 0/7] builtin/repo: introduce stats subcommand

Greetings,

The shape of a repository's history can have huge impacts on the performance and health of the repository itself. Currently, Git lacks a means to surface key stats/information regarding the shape of a repository via a single command. Acquiring this information requires users to be fairly knowledgeable about the structure of a Git repository and how to identify the relevant data points. To fill this gap, supplemental tools such as git-sizer(1) have been developed.

To allow users to more readily identify potential issues for a repository, introduce the "stats" subcommand in git-repo(1) to output stats for the repository that may be of interest to users. The goal of this subcommand is to eventually provide similar functionality to git-sizer(1), but in Git natively.

In this initial version, the "stats" subcommand only surfaces counts of the various reference and object types in a repository. In a follow-up series, I would like to introduce additional data points that are present in git-sizer(1) such as largest objects, combined object sizes by type, and other general repository shape information.

Some other general features that would be nice to introduce eventually:

- A "level of concern" meter for reported stats. This could indicate to
  users which stats may be worth looking into further.
- Links to OIDs of interesting objects that correspond to certain stats.
- Options to limit which references to use when evaluating the
  repository.

Changes since V3:

- Changed from using strlen() to utf8_strlen() to take into
  consideration that translatable strings may have characters that are
  more than one byte.

Changes since V2:

- Added clang-format patch to address false postive triggered in this
  series.
- Use varargs for stats_table_add() family of functions.
- Print to stdout directly instead of using strbuf.
- Add parse_option() earlier in the series.
- Use start_delayed_progress() instead of start_progress().
- Add test to validate --[no-]progress options.
- Some other small fixes.

Changes since V1:

- Translatable terms displayed in the table have formatting separated
  out.
- Squashed the `keyvalue` and `nul` output format patches into one.
- Added a progress meter to provide users with more feedback.
- Updated docs to outline to outline reported data in a bulleted list.
- Combined similar tests together to reduce repetitive setup.
- Added patch to improve ref-filter interface so we don't have to create
  a dummy patterns array.
- Many other renames and cleanups to improve patch clarity.

Thanks, -Justin

Justin Tobler (7):
  builtin/repo: rename repo_info() to cmd_repo_info()
  ref-filter: allow NULL filter pattern
  clang-format: exclude control macros from SpaceBeforeParens
  builtin/repo: introduce stats subcommand
  builtin/repo: add object counts in stats output
  builtin/repo: add keyvalue and nul format for stats
  builtin/repo: add progress meter for stats

 .clang-format               |   2 +-
 Documentation/git-repo.adoc |  30 +++
 builtin/repo.c              | 374 +++++++++++++++++++++++++++++++++++-
 ref-filter.c                |   4 +-
 t/meson.build               |   1 +
 t/t1901-repo-stats.sh       | 129 +++++++++++++
 6 files changed, 534 insertions(+), 6 deletions(-)
 create mode 100755 t/t1901-repo-stats.sh

Range-diff against v3:
1:  ed04168562 = 1:  ed04168562 builtin/repo: rename repo_info() to cmd_repo_info()
2:  6aa76d1323 = 2:  6aa76d1323 ref-filter: allow NULL filter pattern
3:  02a3fcc5fb = 3:  02a3fcc5fb clang-format: exclude control macros from SpaceBeforeParens
4:  12cfbdc464 ! 4:  8ec9914886 builtin/repo: introduce stats subcommand
    @@ builtin/repo.c
      #include "strbuf.h"
     +#include "string-list.h"
      #include "shallow.h"
    ++#include "utf8.h"
      
      static const char *const repo_usage[] = {
      	"git repo info [--format=(keyvalue|nul)] [-z] [<key>...]",
    @@ builtin/repo.c: static int cmd_repo_info(int argc, const char **argv, const char
     +	size_t name_width;
     +
     +	strbuf_vaddf(&buf, format, ap);
    -+	formatted_name = strbuf_detach(&buf, &name_width);
    ++	formatted_name = strbuf_detach(&buf, NULL);
    ++	name_width = utf8_strwidth(formatted_name);
     +
     +	item = string_list_append_nodup(&table->rows, formatted_name);
     +	item->util = entry;
    @@ builtin/repo.c: static int cmd_repo_info(int argc, const char **argv, const char
     +	if (name_width > table->name_col_width)
     +		table->name_col_width = name_width;
     +	if (entry) {
    -+		size_t value_width = strlen(entry->value);
    ++		size_t value_width = utf8_strwidth(entry->value);
     +		if (value_width > table->value_col_width)
     +			table->value_col_width = value_width;
     +	}
    @@ builtin/repo.c: static int cmd_repo_info(int argc, const char **argv, const char
     +{
     +	const char *name_col_title = _("Repository stats");
     +	const char *value_col_title = _("Value");
    -+	size_t name_title_len = strlen(name_col_title);
    -+	size_t value_title_len = strlen(value_col_title);
    ++	size_t name_title_len = utf8_strwidth(name_col_title);
    ++	size_t value_title_len = utf8_strwidth(value_col_title);
     +	struct string_list_item *item;
     +	int name_col_width;
     +	int value_col_width;
5:  ab27340d58 = 5:  584d35f2c7 builtin/repo: add object counts in stats output
6:  f69110224d = 6:  76975b2eab builtin/repo: add keyvalue and nul format for stats
7:  cff5e183bb = 7:  1105346a3c builtin/repo: add progress meter for stats

base-commit: ca2559c1d630eb4f04cdee2328aaf1c768907a9e