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From: Junio C Hamano <gitster@pobox.com>
To: "Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>
Cc: git@vger.kernel.org, Johannes Schindelin <johannes.schindelin@gmx.de>
Subject: Re: [PATCH 2/7] help -a: do not list commands that are excluded from the build
Date: Mon, 15 Apr 2019 16:08:55 +0900	[thread overview]
Message-ID: <xmqqo957sq2g.fsf@gitster-ct.c.googlers.com> (raw)
In-Reply-To: 7dc5293e9e0f8997674b1273393f22954e72c4cd.1555070430.git.gitgitgadget@gmail.com

"Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>
writes:

> From: Johannes Schindelin <johannes.schindelin@gmx.de>
>
> When built with NO_CURL or with NO_UNIX_SOCKETS, some commands are
> skipped from the build. It does not make sense to list them in the
> output of `git help -a`, so let's just not.

The objective makes sense quite a lot.

>  command-list.h: $(wildcard Documentation/git*.txt) Documentation/*config.txt Documentation/config/*.txt
> -	$(QUIET_GEN)$(SHELL_PATH) ./generate-cmdlist.sh command-list.txt >$@+ && mv $@+ $@
> +	$(QUIET_GEN)$(SHELL_PATH) ./generate-cmdlist.sh \
> +		$(patsubst %,--exclude-program %,$(EXCLUDED_PROGRAMS)) \

Each whitespace separated token on $(EXCLUDED_PROGRAMS) is the name
of a program to be excluded and we know there is no funny characters
in it, hence quoing in "^$1 " (without protecting us against
funnies) is sufficient.

> +		command-list.txt >$@+ && mv $@+ $@
>  
>  SCRIPT_DEFINES = $(SHELL_PATH_SQ):$(DIFF_SQ):$(GIT_VERSION):\
>  	$(localedir_SQ):$(NO_CURL):$(USE_GETTEXT_SCHEME):$(SANE_TOOL_PATH_SQ):\
> diff --git a/generate-cmdlist.sh b/generate-cmdlist.sh
> index 709d67405b..7867b99d19 100755
> --- a/generate-cmdlist.sh
> +++ b/generate-cmdlist.sh
> @@ -6,7 +6,7 @@ die () {
>  }
>  
>  command_list () {
> -	grep -v '^#' "$1"
> +	eval grep -ve '^#' $exclude_programs "$1"

The original protects against $IFS in the filename given as $1, but
with the eval that is no longer true.  We have been feeding the
constant "command-list.txt" to the program since its inception, and
I do not expect it to change, so this regression in defensiveness
does not matter in practice.  Also because # is prefixed with ^, the
unintended loss of quotes around it when the eval makes the shell
re-parse the generated command line would not make the remainder
into a comment.

But it does look brittle, and smells like a trap for less
experienced shell programmers to blindly copy & paste & tweak
without understanding what is going on, leading to bugs.

	eval "grep -v -e '^#' $exclude_programs" <"$1"

or something like that, perhaps?

> @@ -93,6 +93,14 @@ EOF
>  EOF
>  }
>  
> +exclude_programs=
> +while test "a$1" = "a--exclude-program"

s/a/z/g; if you want to pretend to be old-fashioned, but s/a//g;
should be sufficient in the modern world.

> +do
> +	shift
> +	exclude_programs="$exclude_programs -e \"^$1 \""
> +	shift
> +done

As I said, this part looks good enough given the things we feed as
parameters to --exclude-program option.

Thanks.

  reply	other threads:[~2019-04-15  7:09 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-12 12:00 [PATCH 0/7] Assorted Documentation-related fixes Johannes Schindelin via GitGitGadget
2019-04-12 12:00 ` [PATCH 1/7] remote-testgit: move it into the support directory for t5801 Johannes Schindelin via GitGitGadget
2019-04-15  7:08   ` Junio C Hamano
2019-04-18 11:46     ` Johannes Schindelin
2019-04-12 12:00 ` [PATCH 2/7] help -a: do not list commands that are excluded from the build Johannes Schindelin via GitGitGadget
2019-04-15  7:08   ` Junio C Hamano [this message]
2019-04-18 12:06     ` Johannes Schindelin
2019-04-12 12:00 ` [PATCH 3/7] check-docs: do not pretend that commands are listed which are excluded Johannes Schindelin via GitGitGadget
2019-04-15  7:18   ` Junio C Hamano
2019-04-18 12:41     ` Johannes Schindelin
2019-04-12 12:00 ` [PATCH 4/7] docs: exclude documentation for commands that have been excluded Johannes Schindelin via GitGitGadget
2019-04-12 18:46   ` Eric Sunshine
2019-04-15  3:09     ` Junio C Hamano
2019-04-15  4:16       ` Eric Sunshine
2019-04-15  4:18         ` Eric Sunshine
2019-04-18 13:08           ` Johannes Schindelin
2019-04-15 14:50         ` Jeff King
2019-04-16  4:12           ` Junio C Hamano
2019-04-18 13:06           ` Johannes Schindelin
2019-04-18 16:01             ` Jeff King
2019-04-12 12:00 ` [PATCH 5/7] check-docs: do not bother checking for legacy scripts' documentation Johannes Schindelin via GitGitGadget
2019-04-15  7:19   ` Junio C Hamano
2019-04-12 12:00 ` [PATCH 6/7] test-tool: handle the `-C <directory>` option just like `git` Johannes Schindelin via GitGitGadget
2019-04-12 12:00 ` [PATCH 7/7] Turn `git serve` into a test helper Johannes Schindelin via GitGitGadget
2019-04-15 14:03   ` Junio C Hamano
2019-04-17  3:46     ` Jeff King
2019-04-17  5:40       ` Junio C Hamano
2019-04-17 18:22         ` Josh Steadmon
2019-04-18  1:58           ` Junio C Hamano
2019-04-18 12:17     ` Johannes Schindelin
2019-04-18 13:16 ` [PATCH v2 0/8] Assorted Documentation-related fixes Johannes Schindelin via GitGitGadget
2019-04-18 13:16   ` [PATCH v2 1/8] remote-testgit: move it into the support directory for t5801 Johannes Schindelin via GitGitGadget
2019-04-18 13:16   ` [PATCH v2 2/8] Makefile: drop the NO_INSTALL variable Johannes Schindelin via GitGitGadget
2019-04-18 13:16   ` [PATCH v2 3/8] help -a: do not list commands that are excluded from the build Johannes Schindelin via GitGitGadget
2019-04-18 13:16   ` [PATCH v2 4/8] check-docs: allow command-list.txt to contain excluded commands Johannes Schindelin via GitGitGadget
2019-04-18 13:16   ` [PATCH v2 5/8] docs: exclude documentation for commands that have been excluded Johannes Schindelin via GitGitGadget
2019-04-19  5:20     ` Junio C Hamano
2019-04-29 12:28       ` Johannes Schindelin
2019-04-18 13:16   ` [PATCH v2 6/8] check-docs: do not bother checking for legacy scripts' documentation Johannes Schindelin via GitGitGadget
2019-04-18 13:16   ` [PATCH v2 7/8] test-tool: handle the `-C <directory>` option just like `git` Johannes Schindelin via GitGitGadget
2019-04-18 13:16   ` [PATCH v2 8/8] Turn `git serve` into a test helper Johannes Schindelin via GitGitGadget

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