Switch tar verification to a manifest comparison.

toolchain/install/BUILD

@@ -4,6 +4,7 @@
 
 load("@rules_cc//cc:defs.bzl", "cc_binary", "cc_library", "cc_test")
 load("//bazel/cc_toolchains:defs.bzl", "cc_env")
+load("//bazel/manifest:defs.bzl", "manifest")
 load("install_filegroups.bzl", "install_filegroup", "install_symlink", "install_target", "make_install_filegroups")
 load("pkg_helpers.bzl", "pkg_naming_variables", "pkg_tar_and_test")
 load("run_tool.bzl", "run_tool")
@@ -145,6 +146,11 @@ make_install_filegroups(
     prefix = "prefix_root",
 )
 
+manifest(
+    name = "install_data_manifest.txt",
+    srcs = [":install_data"],
+)
+
 pkg_naming_variables(
     name = "packaging_variables",
 )
@@ -157,18 +163,12 @@ pkg_naming_variables(
 # `carbon_toolchain_tar_gz_rule`.
 pkg_tar_and_test(
     srcs = [":pkg_data"],
+    install_data_manifest = ":install_data_manifest.txt",
     name_base = "carbon_toolchain",
     package_dir = "carbon_toolchain-$(version)",
     package_file_name_base = "carbon_toolchain-$(version)",
     package_variables = ":packaging_variables",
     stamp = -1,  # Allow `--stamp` builds to produce file timestamps.
-    test_data = [
-        ":install_data",
-    ],
-    # TODO: This is used to make sure that tar files are in install_data (one
-    # direction). Replace with a check that the files in install_data and tar
-    # match (bidirectional).
-    test_install_marker = "prefix_root/lib/carbon/carbon_install.txt",
 )
 
 # Support `bazel run` on specific binaries.

toolchain/install/pkg_helpers.bzl

@@ -25,7 +25,7 @@ pkg_naming_variables = rule(
     attrs = VERSION_ATTRS,
 )
 
-def pkg_tar_and_test(name_base, package_file_name_base, test_data, test_install_marker, **kwargs):
+def pkg_tar_and_test(name_base, package_file_name_base, install_data_manifest, **kwargs):
     """Create a `pkg_tar` and a test for both `.tar` and `.tar.gz` extensions.
 
     Args:
@@ -35,10 +35,8 @@ def pkg_tar_and_test(name_base, package_file_name_base, test_data, test_install_
         package_file_name_base:
             The base of the `package_file_name` attribute to `pkg_tar`. The file
             extensions will be appended after a `.`.
-        test_data:
-            The test data to verify the tar file against.
-        test_install_marker:
-            The install marker within the test data to locate the installation.
+        install_data_manifest:
+            The install data manifest file to compare with.
         **kwargs:
             Passed to `pkg_tar` for all the rest of its attributes.
     """
@@ -58,10 +56,10 @@ def pkg_tar_and_test(name_base, package_file_name_base, test_data, test_install_
             name = name_base + "_" + target_ext + "_test",
             size = "small",
             srcs = ["toolchain_tar_test.py"],
-            data = [":" + tar_target, test_install_marker] + test_data,
+            data = [":" + tar_target, install_data_manifest],
             args = [
                 "$(location :{})".format(tar_target),
-                "$(location {})".format(test_install_marker),
+                "$(location {})".format(install_data_manifest),
             ],
             main = "toolchain_tar_test.py",
             # The compressed tar is slow, exclude building and testing that.

toolchain/install/toolchain_tar_test.py

@@ -9,11 +9,21 @@
 """
 
 import argparse
-import sys
 from pathlib import Path
+import re
 import tarfile
 
 
+def expect_empty_set(filename: str, file_set: set[str]) -> bool:
+    """Prints and returns false when the set has entries."""
+    if file_set:
+        print(f"error: files only in `{filename}`:")
+        for f in file_set:
+            print(f"  - ${f}")
+        return False
+    return True
+
+
 def main() -> None:
     parser = argparse.ArgumentParser(description=__doc__)
     parser.add_argument(
@@ -22,42 +32,42 @@ def main() -> None:
         help="The tar file to test.",
     )
     parser.add_argument(
-        "install_marker",
+        "install_data_manifest",
         type=Path,
-        help="The path of the install marker in a prefix root to test against.",
+        help="The install data manifest file.",
     )
     args = parser.parse_args()
 
-    # Locate the prefix root from the install marker.
-    if not args.install_marker.exists():
-        sys.exit("ERROR: No install marker: " + args.install_marker)
-    prefix_root_path = args.install_marker.parents[2]
+    # Gather install data files.
+    with open(args.install_data_manifest) as manifest:
+        # Remove everything up to and including `prefix_root`.
+        install_files = set(
+            [
+                re.sub("^.*/prefix_root/", "", entry.strip())
+                for entry in manifest.readlines()
+            ]
+        )
+    assert len(install_files), f"`{args.install_data_manifest}` is empty."
 
-    # First check that every file and directory in the tar file exists in our
-    # prefix root, and build a set of those paths.
-    installed_paths = set()
+    # Gather tar files.
     with tarfile.open(args.tar_file) as tar:
-        for tarinfo in tar:
-            relative_path = Path(*Path(tarinfo.name).parts[1:])
-            installed_paths.add(relative_path)
-            if not prefix_root_path.joinpath(relative_path).exists():
-                sys.exit(
-                    "ERROR: File `{0}` is not in prefix root: `{1}`".format(
-                        tarinfo.name, prefix_root_path
-                    )
-                )
+        # Remove the first path component.
+        tar_files = set(
+            [
+                str(Path(*Path(tarinfo.name).parts[1:]))
+                for tarinfo in tar
+                if not tarinfo.isdir()
+            ]
+        )
+    assert len(tar_files), f"`{args.tar_file}` is empty."
 
-    # If we found an empty tar file, it's always an error.
-    if len(installed_paths) == 0:
-        sys.exit("ERROR: Tar file `{0}` was empty.".format(args.tar_file))
-
-    # Now check that every file and directory in the prefix root is in that set.
-    for prefix_path in prefix_root_path.glob("**/*"):
-        relative_path = prefix_path.relative_to(prefix_root_path)
-        if relative_path not in installed_paths:
-            sys.exit(
-                "ERROR: File `{0}` is not in tar file.".format(relative_path)
-            )
+    # Verify file sets match.
+    tar_okay = expect_empty_set(args.tar_file, tar_files - install_files)
+    install_okay = expect_empty_set(
+        args.install_data_manifest, install_files - tar_files
+    )
+    if not (tar_okay and install_okay):
+        exit("error: tar and install data did not match.")
 
 
 if __name__ == "__main__":