Add `gdb-repr` directive for `tests/debuginfo` - #160377

Walnut356 · 2026-08-02T09:39:25Z

Part of #148483 and followup to #158298. Applies (approximately) identical logic to GDB.

I still need to test things on windows-gnu (and locally try a few more tests to see if there's any glaring issues). There's also a few bike-sheddy things.

The main way this differs from the LLDB implementation is that GDB doesn't use lldb_batchmode/runner.py to orchestrate the commands. Instead, I have compiletest import from_gdb.py which registers a custom repr CLI command. GDB's batch processing works as normal, but dispatches to our logic automatically whenever it encounters repr <var_name>.

An additional repr-finalize CLI command is also registered to implement the checks that ensure we encountered all expected types/vars, and verifies that there were no errors before saving blessed data.

r? @Kobzol, @jieyouxu

rustbot · 2026-08-02T09:39:30Z

Kobzol is not on the review rotation at the moment.
They may take a while to respond.

Walnut356 · 2026-08-02T09:41:08Z

+class ReprCommand(gdb.Command):
+    def __init__(self):
+        super().__init__("repr", gdb.COMMAND_OBSCURE)
+
+    def invoke(self, argument: str, from_tty: bool):
+        print(f"(gdb) repr {argument}")
+
+        global REPR_COMMAND_RUN
+        REPR_COMMAND_RUN = True
+        try:
+            if check(argument) == Result.Mismatch:
+                global REPR_ERROR
+                REPR_ERROR = True
+        except Exception as e:
+            import sys
+            import traceback
+
+            traceback.print_exception(type(e), e, e.__traceback__, file=sys.stdout)
+            gdb.execute("exit 1")
+
+
+ReprCommand()
+
+
+class ReprFinalize(gdb.Command):
+    def __init__(self):
+        super().__init__("repr_finalize", gdb.COMMAND_OBSCURE)
+
+    def invoke(self, argument: str, from_tty: bool):
+        if not REPR_COMMAND_RUN:
+            return
+
+        if not tested_all_variables() or not tested_all_types():
+            gdb.execute("exit 1")
+
+        if BLESS and not REPR_ERROR:
+            gdb_version = gdb.execute("show version", to_string=True).splitlines()[0]
+            metadata = BlessMetadata(sys.version, gdb_version)
+            INPUT_DATA.save_blessing(metadata)
+
+
+ReprFinalize()


Here's where we create and register the custom CLI commands.

View changes since the review

Walnut356 · 2026-08-02T09:45:00Z

+TYPES_TESTED: dict[str, Result] = {}
+"""Since types are unique and unchanging, we only need to test each type once. This also helps
+ensure we have tested all types in `INPUT_DATA`
+"""
+
+
+VARS_TESTED: list[dict[str, Result]] = []
+"""Used to help ensure all expected variables were tested. Each element of the list corresponds to a
+breakpoint, and contains a set of all of the variable names tested for that breakpoint."""
+
+
+def tested_all_types() -> bool:
+    """Returns true if all types in INPUT_DATA were tested this run."""
+
+    expected_types = set(INPUT_DATA.types)
+    untested_types = expected_types.difference(TYPES_TESTED.keys())
+
+    if len(untested_types) != 0:
+        print(
+            f"{ANSI_RED}[repr error]{ANSI_END} The following types were expected, but were not \
+tested:\n  {untested_types}"
+        )
+
+    return len(untested_types) == 0
+
+
+def tested_all_variables() -> bool:
+    expected_vars = [set(vars) for vars in INPUT_DATA.breakpoints]
+    untested_vars = [
+        expected.difference(tested.keys())
+        for expected, tested in zip(expected_vars, VARS_TESTED)
+    ]
+
+    tested_not_expected = [
+        set(tested.keys()).difference(expected)
+        for expected, tested in zip(expected_vars, VARS_TESTED)
+    ]
+
+    result = True
+
+    for i, v in enumerate(untested_vars):
+        if len(v) == 0:
+            continue
+
+        result = False
+        print(
+            f"{ANSI_RED}[repr error]{ANSI_END} The following variables were expected at \
+breakpoint#{i}, but were not tested:\n  {v}"
+        )
+
+    for i, v in enumerate(tested_not_expected):
+        if len(v) == 0:
+            continue
+
+        result = False
+        print(
+            f"{ANSI_RED}[repr error]{ANSI_END} The following variables were tested, but do not \
+exist in the input data at breakpoint#{i}:\n  {v}"
+        )
+
+    return result


These were just moved from check_lldb.py.

I might be able to factor more of the checking logic out and share it between lldb and gdb. There are less differences for their API than I was expecting. It would probably require passing a few wrappers to the check function that abstract away the debugger-specific accesses, but we'll see.

View changes since the review

Walnut356 · 2026-08-02T09:54:46Z

-            gdb.args(debugger_opts).env("PYTHONPATH", pythonpath);
+            gdb.args(debugger_opts)
+                .env("PYTHONPATH", pythonpath)
+                .env("BATCHMODE_DEBUGGER", "gdb")


The bike-shedding I mentioned more or less has to do with these env vars and the lldb_batchmode package. With GDB support, we'll probably want to re-name lldb_batchmode (and probably rename runner.py to lldb_batchmode.py), but I'm not super happy with any of the names that came to mind. Maybe just batchmode?

View changes since the review

Walnut356 · 2026-08-02T10:17:44Z

Oh yeah, i need to gate it so it doesn't check for the file path until a repr command has been run

rustbot assigned Kobzol Aug 2, 2026

Walnut356 commented Aug 2, 2026

View reviewed changes

This comment has been minimized.

Sign in to view

Walnut356 force-pushed the gdb_di_repr branch from ce99e97 to dbc2a1e Compare August 2, 2026 10:15

This comment has been minimized.

Sign in to view

Walnut356 force-pushed the gdb_di_repr branch from dbc2a1e to 1114ab2 Compare August 3, 2026 08:21

This comment has been minimized.

Sign in to view

Walnut356 added 2 commits August 3, 2026 04:13

Add gdb-repr directive

2364955

convert basic-types to gdb-repr

f25a55b

Walnut356 force-pushed the gdb_di_repr branch from 1114ab2 to f25a55b Compare August 3, 2026 09:14

Navigation Menu

Uh oh!

Uh oh!

Add `gdb-repr` directive for `tests/debuginfo` - #160377