dotnet/runtime · error · RuntimeError

Expected a '.ilc.rsp' file for nativeaot, but got {original_

Error message

Expected a '.ilc.rsp' file for nativeaot, but got {original_rsp_filepath}

What it means

Raised inside the async `run_nativeaot` worker (superpmi.py:1187-1189) during a nativeaot collection. Every entry passed via `-ilc_rsps` must be an ILC response file whose name ends in `.ilc.rsp`; anything else is rejected before the rsp is parsed and rewritten. The collection only understands native AOT ilc.rsp inputs, so a different file type cannot be processed.

Source

Thrown at src/coreclr/scripts/superpmi.py:1189

                # Note: crossgen2 compiles in parallel by default. However, it seems to lead to sharing violations
                # in SuperPMI collection, accessing the MC file. So, disable crossgen2 parallism by using
                # the "--parallelism:1" switch, and allowing coarse-grained (per-assembly) parallelism here.
                # It turns out this works better anyway, as there is a lot of non-parallel time between
                # crossgen2 parallel compilations.
                helper = AsyncSubprocessHelper(assemblies, verbose=True)
                helper.run_to_completion(run_crossgen2, self)

                os.environ.clear()
                os.environ.update(old_env)
            ################################################################################################ end of "self.coreclr_args.crossgen2 is True"

            ################################################################################################ Do collection using nativeaot
            if self.coreclr_args.nativeaot is True:
                logging.debug("Starting collection using nativeaot")

                async def run_nativeaot(print_prefix, original_rsp_filepath, self):
                    if not original_rsp_filepath.endswith(".ilc.rsp"):
                        raise RuntimeError(f"Expected a '.ilc.rsp' file for nativeaot, but got {original_rsp_filepath}")

                    # The contents of the rsp contain many knobs and arguments that represent customer scenarios.
                    # Make a copy of the .ilc.rsp file as we are going to modify it. We do not want to modify the original one.
                    # The modifications include re-writing paths for references, input assembly and the output.
                    # We do this because the current paths in the rsp *may* not exist by the time we want to run ilc.
                    rsp_filepath = os.path.join(self.temp_location, make_safe_filename("nativeaot_" + original_rsp_filepath) + ".rsp")
                    shutil.copyfile(original_rsp_filepath, rsp_filepath)

                    rsp_file = open(rsp_filepath, "r")
                    rsp_contents = rsp_file.readlines()
                    rsp_file.close()

                    original_input_filepath = ""

                    for line in rsp_contents:
                        if not line.startswith("-"):
                            original_input_filepath = line

View on GitHub (pinned to 290d5ab72c)

Solutions

1. Ensure every path in `-ilc_rsps` is an actual `*.ilc.rsp` file produced by the native AOT build.
2. If you passed a directory, enumerate its `.ilc.rsp` files and pass those explicit paths.
3. Filter the list with a shell glob like `-ilc_rsps path/**/*.ilc.rsp` to exclude unrelated files.

Example fix

// before
superpmi.py collect --nativeaot -ilc_rsps tests/ComWrappers/native/ComWrappers.csproj
// after
superpmi.py collect --nativeaot -ilc_rsps tests/ComWrappers/native/ComWrappers.ilc.rsp

# Validate ilc_rsp inputs before launching the nativeaot collection
ilc_rsps = [p for p in args.ilc_rsps]
bad = [p for p in ilc_rsps if not p.endswith('.ilc.rsp')]
if bad:
    raise SystemExit('All -ilc_rsps entries must end in .ilc.rsp; offending: ' + ', '.join(bad))

When it happens

Trigger: Invoking `superpmi.py collect --nativeaot -ilc_rsps <path>` where one of the supplied paths does not end with `.ilc.rsp` (e.g. a directory, a `.dll`, a `.csproj`, or a generic `.rsp`). The AsyncSubprocessHelper dispatches each path to run_nativeaot, which fails on the first non-matching path.

Common situations: Passing a parent directory or a glob expansion that includes non-rsp files to `-ilc_rsps`; pointing at a plain crossgen2/csc response file instead of the ILC-generated `.ilc.rsp`; typo in the filename extension.

Related errors

• Unable to find input file in {original_rsp_filepath}
• Tiering options have no effect for nativeaot collections.
• Pass only one tiering option.
• No .mc files generated.
• PMI not found at {}

AI-assisted analysis of dotnet/runtime@290d5ab72c (2026-08-06). Data as JSON: /api/errors/c2eb3651a63aa3bb. Report an issue: GitHub.