Add a simple reproducibility test command.reprotest

1 files changed, 130 insertions, 0 deletions

diff --git a/mesonbuild/scripts/reprotest.py b/mesonbuild/scripts/reprotest.py
new file mode 100755
index 0000000..165c450
--- /dev/null
+++ b/mesonbuild/scripts/reprotest.py
@@ -0,0 +1,130 @@
+# SPDX-License-Identifier: Apache-2.0
+# Copyright 2024 The Meson development team
+
+from __future__ import annotations
+
+import sys, os, subprocess, shutil
+import pathlib
+import typing as T
+
+if T.TYPE_CHECKING:
+    import argparse
+
+from ..mesonlib import get_meson_command
+
+# Note: when adding arguments, please also add them to the completion
+# scripts in $MESONSRC/data/shell-completions/
+def add_arguments(parser: 'argparse.ArgumentParser') -> None:
+    parser.add_argument('--intermediaries',
+                        default=False,
+                        action='store_true',
+                        help='Check intermediate files.')
+    parser.add_argument('mesonargs', nargs='*',
+                        help='Arguments to pass to "meson setup".')
+
+IGNORE_PATTERNS = ('.ninja_log',
+                   '.ninja_deps',
+                   'meson-private',
+                   'meson-logs',
+                   'meson-info',
+                   )
+
+INTERMEDIATE_EXTENSIONS = ('.gch',
+                           '.pch',
+                           '.o',
+                           '.obj',
+                           '.class',
+                           )
+
+class ReproTester:
+    def __init__(self, options: T.Any):
+        self.args = options.mesonargs
+        self.meson = get_meson_command()[:]
+        self.builddir = pathlib.Path('buildrepro')
+        self.storagedir = pathlib.Path('buildrepro.1st')
+        self.issues: T.List[str] = []
+        self.check_intermediaries = options.intermediaries
+
+    def run(self) -> int:
+        if not pathlib.Path('meson.build').is_file():
+            sys.exit('This command needs to be run at your project source root.')
+        self.check_ccache()
+        self.cleanup()
+        self.build()
+        self.check_output()
+        self.print_results()
+        if not self.issues:
+            self.cleanup()
+        return len(self.issues)
+
+    def check_ccache(self) -> None:
+        for evar in ('CC', 'CXX'):
+            evalue = os.environ.get(evar, '')
+            if 'ccache' in evalue:
+                print(f'Environment variable {evar} set to value "{evalue}".')
+                print('This implies using a compiler cache, which is incompatible with reproducible builds.')
+                sys.exit(1)
+
+    def cleanup(self) -> None:
+        if self.builddir.exists():
+            shutil.rmtree(self.builddir)
+        if self.storagedir.exists():
+            shutil.rmtree(self.storagedir)
+
+    def build(self) -> None:
+        setup_command: T.Sequence[T.Union[pathlib.Path, str]] = self.meson + ['setup', self.builddir] + self.args
+        build_command: T.Sequence[T.Union[pathlib.Path, str]] = self.meson + ['compile', '-C', self.builddir]
+        subprocess.check_call(setup_command)
+        subprocess.check_call(build_command)
+        self.builddir.rename(self.storagedir)
+        subprocess.check_call(setup_command)
+        subprocess.check_call(build_command)
+
+    def ignore_file(self, fstr: str) -> bool:
+        for p in IGNORE_PATTERNS:
+            if p in fstr:
+                return True
+        if not self.check_intermediaries:
+            for e in INTERMEDIATE_EXTENSIONS:
+                if fstr.endswith(e):
+                    return True
+        return False
+
+    def check_contents(self, fromdir: str, todir: str, check_contents: bool) -> None:
+        frompath = fromdir + '/'
+        topath = todir + '/'
+        for fromfile in pathlib.Path(fromdir).glob('**/*'):
+            if not fromfile.is_file():
+                continue
+            fstr = str(fromfile)
+            if self.ignore_file(fstr):
+                continue
+            assert fstr.startswith(frompath)
+            tofile = pathlib.Path(fstr.replace(frompath, topath, 1))
+            if not tofile.exists():
+                self.issues.append(f'Missing file: {tofile}')
+            elif check_contents:
+                fromdata = fromfile.read_bytes()
+                todata = tofile.read_bytes()
+                if fromdata != todata:
+                    self.issues.append(f'File contents differ: {fromfile}')
+
+    def print_results(self) -> None:
+        if self.issues:
+            print('Build differences detected')
+            for i in self.issues:
+                print(i)
+        else:
+            print('No differences detected.')
+
+    def check_output(self) -> None:
+        self.check_contents('buildrepro', 'buildrepro.1st', True)
+        self.check_contents('buildrepro.1st', 'buildrepro', False)
+
+def run(options: T.Any) -> None:
+    rt = ReproTester(options)
+    try:
+        sys.exit(rt.run())
+    except FileNotFoundError as e:
+        print(e)
+        sys.exit(1)