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[PATCH v2] doc: option value may be separate for valid reasons

From
Junio C Hamano <gitster@pobox.com>
Date
Nov 25, 2024, 03:14 UTC
Message-ID
<xmqqh67w6m4m.fsf@gitster.g>
In-Reply-To
<xmqqjzct9db8.fsf@gitster.g>

Even though `git help cli` recommends users to prefer using "--option=value" over "--option value", there can be reasons why giving them separately is a good idea. One reason is that shells do not perform tilde expansion for `--option=~/path/name` but they expand `--options ~/path/name` just fine.

This is not a problem for many options whose option parsing is properly written using OPT_FILENAME(), because the value given to OPT_FILENAME() is tilde-expanded internally by us, but some commands take a pathname as a mere string, which needs this trick to have the shell help us.

I think the reason we originally decided to recommend the stuck form was because an option that takes an optional value requires you to use it in the stuck form, and it is one less thing for users to worry about if they get into the habit to always use the stuck form. But we should be discouraging ourselves from adding an option with an optional value in the first place, and we might want to weaken the current recommendation.

In any case, let's describe this one case where it is necessary to use the separate form, with an example.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Documentation/gitcli.txt         | 9 +++++++++
 Documentation/gitcredentials.txt | 6 ++++++
 2 files changed, 15 insertions(+)
diff --git a/Documentation/gitcli.txt b/Documentation/gitcli.txt
index 7c709324ba..bd62cbd043 100644
--- a/Documentation/gitcli.txt
+++ b/Documentation/gitcli.txt
@@ -90,6 +90,15 @@ scripting Git:
    for long options.  An option that takes optional option-argument must be
    written in the 'stuck' form.
 
+ * Despite the above suggestion, when Arg is a path relative to the
+   home directory of a user, e.g. ~/directory/file or ~u/d/f, you
+   may want to use the separate form, e.g. `git foo --file ~/mine`,
+   not `git foo --file=~/mine`.  The shell will expand `~/` in the
+   former to your home directory, but most shells keep the tilde in
+   the latter.  Some of our commands know how to tilde-expand the
+   option value even when given in the stuck form, but not all of
+   them do.
+
  * When you give a revision parameter to a command, make sure the parameter is
    not ambiguous with a name of a file in the work tree.  E.g. do not write
    `git log -1 HEAD` but write `git log -1 HEAD --`; the former will not work
diff --git a/Documentation/gitcredentials.txt b/Documentation/gitcredentials.txt
index 71dd19731a..35a7452c8f 100644
--- a/Documentation/gitcredentials.txt
+++ b/Documentation/gitcredentials.txt
@@ -242,6 +242,12 @@ Here are some example specifications:
 [credential]
 	helper = "foo --bar='whitespace arg'"
 
+# store helper (discouraged) with custom location for the db file;
+# use `--file ~/.git-secret.txt`, rather than `--file=~/.git-secret.txt`,
+# to allow the shell to expand tilde to the home directory.
+[credential]
+	helper = "store --file ~/.git-secret.txt"
+
 # you can also use an absolute path, which will not use the git wrapper
 [credential]
 	helper = "/path/to/my/helper --with-arguments"

Interdiff:
  diff --git a/Documentation/gitcli.txt b/Documentation/gitcli.txt
  index e484be9a36..bd62cbd043 100644
  --- a/Documentation/gitcli.txt
  +++ b/Documentation/gitcli.txt
  @@ -92,13 +92,12 @@ scripting Git:
   
    * Despite the above suggestion, when Arg is a path relative to the
      home directory of a user, e.g. ~/directory/file or ~u/d/f, you
  -   may want to use the separate form, e.g. `git credential-store
  -   --file ~/sec/rit`, not `git credential-store --file=~/sec/rit`.
  -   The shell will expand `~/` in the former to your home directory,
  -   but most shells keep the tilde in the latter.  Some of our
  -   commands know how to tilde-expand the option value internally,
  -   but not all.  The `--file` option of `credential-store` is an
  -   example that it needs shell's help to tilde-expand its value.
  +   may want to use the separate form, e.g. `git foo --file ~/mine`,
  +   not `git foo --file=~/mine`.  The shell will expand `~/` in the
  +   former to your home directory, but most shells keep the tilde in
  +   the latter.  Some of our commands know how to tilde-expand the
  +   option value even when given in the stuck form, but not all of
  +   them do.
   
    * When you give a revision parameter to a command, make sure the parameter is
      not ambiguous with a name of a file in the work tree.  E.g. do not write
  diff --git a/Documentation/gitcredentials.txt b/Documentation/gitcredentials.txt
  index f6ce923f25..35a7452c8f 100644
  --- a/Documentation/gitcredentials.txt
  +++ b/Documentation/gitcredentials.txt
  @@ -243,7 +243,8 @@ Here are some example specifications:
   	helper = "foo --bar='whitespace arg'"
   
   # store helper (discouraged) with custom location for the db file;
  -# tilde expansion often requires the filename as a separate argument.
  +# use `--file ~/.git-secret.txt`, rather than `--file=~/.git-secret.txt`,
  +# to allow the shell to expand tilde to the home directory.
   [credential]
   	helper = "store --file ~/.git-secret.txt"
   
-- 
2.47.0-496-g788c9fe963
Previous: Junio C HamanoNext: Eric Sunshine
Message 4 of 6 in “doc: option value may be separate for valid reasons”
  1. doc: option value may be separate for valid reasonsJunio C Hamano, Nov 24, 2024
  2. Eric SunshineNov 24, 2024
  3. Junio C HamanoNov 25, 2024
  4. doc: option value may be separate for valid reasonsJunio C Hamano, Nov 25, 2024
  5. Eric SunshineNov 25, 2024
  6. Junio C HamanoNov 25, 2024

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