gdb/mi: fix breakpoint script field output

The "script" field, output whenever information about a breakpoint with
commands is output, uses wrong MI syntax.

    $ ./gdb -nx -q --data-directory=data-directory -x script -i mi
    =thread-group-added,id="i1"
    =breakpoint-created,bkpt={number="1",type="breakpoint",disp="keep",enabled="y",addr="0x000000000000111d",func="main",file="test.c",fullname="/home/simark/build/binutils-gdb-one-target/gdb/test.c",line="3",thread-groups=["i1"],times="0",original-location="main"}
    =breakpoint-modified,bkpt={number="1",type="breakpoint",disp="keep",enabled="y",addr="0x000000000000111d",func="main",file="test.c",fullname="/home/simark/build/binutils-gdb-one-target/gdb/test.c",line="3",thread-groups=["i1"],times="0",script={"aaa","bbb","ccc"},original-location="main"}
    (gdb)
    -break-info
    ^done,BreakpointTable={nr_rows="1",nr_cols="6",hdr=[{width="7",alignment="-1",col_name="number",colhdr="Num"},{width="14",alignment="-1",col_name="type",colhdr="Type"},{width="4",alignment="-1",col_name="disp",colhdr="Disp"},{width="3",alignment="-1",col_name="enabled",colhdr="Enb"},{width="18",alignment="-1",col_name="addr",colhdr="Address"},{width="40",alignment="2",col_name="what",colhdr="What"}],body=[bkpt={number="1",type="breakpoint",disp="keep",enabled="y",addr="0x000000000000111d",func="main",file="test.c",fullname="/home/simark/build/binutils-gdb-one-target/gdb/test.c",line="3",thread-groups=["i1"],times="0",script={"aaa","bbb","ccc"},original-location="main"}]}
    (gdb)

In both the =breakpoint-modified and -break-info output, we have:

     script={"aaa","bbb","ccc"}

According to the output syntax [1], curly braces means tuple, and a
tuple contains key=value pairs.  This looks like it should be a list,
but uses curly braces by mistake.  This would make more sense:

    script=["aaa","bbb","ccc"]

Fix it, keeping the backwards compatibility by introducing a new MI
version (MI4), in exactly the same way as was done when fixing
multi-locations breakpoint output in [2].

 - Add a fix_breakpoint_script_output uiout flag.  MI uiouts will use
   this flag if the version is >= 4.
 - Add a fix_breakpoint_script_output_globally variable and the
   -fix-breakpoint-script-output MI command to set it, if frontends want
   to use the fixed output for this without using the newer MI version.
 - When emitting the script field, use list instead of tuple, if we want
   the fixed output (depending on the two criteria above)
 -

[1] https://sourceware.org/gdb/onlinedocs/gdb/GDB_002fMI-Output-Syntax.html#GDB_002fMI-Output-Syntax
[2] https://gitlab.com/gnutools/binutils-gdb/-/commit/b4be1b0648608a2578bbed39841c8ee411773edd

Change-Id: I7113c6892832c8d6805badb06ce42496677e2242
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=24285

1 files changed, 23 insertions, 3 deletions

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 382df00..82cb1c8 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -30472,6 +30472,21 @@ The multiple locations are now placed in a @code{locations} field, whose value
 is a list.
 @end itemize
 
+@item
+@center 4
+@tab
+@center 13.1
+@tab
+
+@itemize
+@item
+The syntax of the "script" field in breakpoint output has changed in the
+responses to the @code{-break-insert} and @code{-break-info} commands, as
+well as the @code{=breakpoint-created} and @code{=breakpoint-modified}
+events.  The previous output was syntactically invalid.  The new output is
+a list.
+@end itemize
+
 @end multitable
 
 If your front end cannot yet migrate to a more recent version of the
@@ -30482,9 +30497,14 @@ available in those recent MI versions, using the following commands:
 
 @item -fix-multi-location-breakpoint-output
 Use the output for multi-location breakpoints which was introduced by
-MI 3, even when using MI versions 2 or 1.  This command has no
+MI 3, even when using MI versions below 3.  This command has no
 effect when using MI version 3 or later.
 
+@item -fix-breakpoint-script-output
+Use the output for the breakpoint "script" field which was introduced by
+MI 4, even when using MI versions below 4.  This command has no effect when
+using MI version 4 or later.
+
 @end table
 
 The best way to avoid unexpected changes in MI that might break your front
@@ -31647,14 +31667,14 @@ The corresponding @value{GDBN} command is @samp{dprintf}.
 4^done,bkpt=@{number="1",type="dprintf",disp="keep",enabled="y",
 addr="0x000000000040061b",func="foo",file="mi-dprintf.c",
 fullname="mi-dprintf.c",line="25",thread-groups=["i1"],
-times="0",script=@{"printf \"At foo entry\\n\"","continue"@},
+times="0",script=["printf \"At foo entry\\n\"","continue"],
 original-location="foo"@}
 (gdb)
 5-dprintf-insert 26 "arg=%d, g=%d\n" arg g
 5^done,bkpt=@{number="2",type="dprintf",disp="keep",enabled="y",
 addr="0x000000000040062a",func="foo",file="mi-dprintf.c",
 fullname="mi-dprintf.c",line="26",thread-groups=["i1"],
-times="0",script=@{"printf \"arg=%d, g=%d\\n\", arg, g","continue"@},
+times="0",script=["printf \"arg=%d, g=%d\\n\", arg, g","continue"],
 original-location="mi-dprintf.c:26"@}
 (gdb)
 @end smallexample