rewriter: drop unused command-line arguments for def/kwargs delete

The `default-options delete` and `kwargs delete` subcommands required
key/value pairs, where the key was deleted and the specified value was
ignored.  This matches the JSON script mode interface but is unpleasant
as a CLI.  Have the CLI `delete` commands accept a list of keys instead.

We can make this change because the UI is documented to be unstable.
However, to allow scripts to work with both old and new Meson, ignore
even-numbered arguments if they're all equal to the empty string.

Fixes: #13234

1 files changed, 16 insertions, 3 deletions

diff --git a/docs/markdown/Rewriter.md b/docs/markdown/Rewriter.md
index 82f86353d..546666f19 100644
--- a/docs/markdown/Rewriter.md
+++ b/docs/markdown/Rewriter.md
@@ -94,7 +94,8 @@ It is also possible to set kwargs of specific functions with the
 rewriter. The general command for setting or removing kwargs is:
 
 ```bash
-meson rewrite kwargs {set/delete} <function type> <function ID> <key1> <value1> <key2> <value2> ...
+meson rewrite kwargs set <function type> <function ID> <key1> <value1> <key2> <value2> ...
+meson rewrite kwargs delete <function type> <function ID> <key1> <key2> ...
 ```
 
 For instance, setting the project version can be achieved with this command:
@@ -116,14 +117,23 @@ converted to `/` by msys bash but in order to keep usage
 shell-agnostic, the rewrite command also allows `//` as the function
 ID such that it will work in both msys bash and other shells.
 
+*Before 1.10.0*, the `delete` command expected `<key> <value>` pairs as
+in `set`; the `<value>` was ignored.  For backward compatibility, Meson
+accepts this syntax with a warning if all `<value>`s are the empty string.
+
 ### Setting the project default options
 
 For setting and deleting default options, use the following command:
 
 ```bash
-meson rewrite default-options {set/delete} <opt1> <value1> <opt2> <value2> ...
+meson rewrite default-options set <opt1> <value1> <opt2> <value2> ...
+meson rewrite default-options delete <opt1> <opt2> ...
 ```
 
+*Before 1.10.0*, the `delete` command expected `<opt> <value>` pairs as
+in `set`; the `<value>` was ignored.  For backward compatibility, Meson
+accepts this syntax with a warning if all `<value>`s are the empty string.
+
 ## Limitations
 
 Rewriting a Meson file is not guaranteed to keep the indentation of
@@ -229,6 +239,9 @@ The format for the type `target` is defined as follows:
 }
 ```
 
+For operation `delete`, the values of the `options` can be anything
+(including `null`).
+
 ### Default options modification format
 
 The format for the type `default_options` is defined as follows:
@@ -246,7 +259,7 @@ The format for the type `default_options` is defined as follows:
 ```
 
 For operation `delete`, the values of the `options` can be anything
-(including `null`)
+(including `null`).
 
 ## Extracting information