Auto merge of #12244 - rev112:package-repro-pure, r=aneeshusa

Create .tar.gz package deterministically using Python's "tarfile"

<!-- Please describe your changes on the following line: -->
A development of #12108, creates a .tar.gz package using the `tarfile` and `gzip` modules, without external dependencies. Fixes #11981.
Also this fixes the issue when the existing `resources/` directory didn't allow to create a new package and failed with "File exists" error.

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #11981 (github issue number if applicable).

<!-- Either: -->
- [ ] There are tests for these changes OR
- [X] These changes do not require tests because "more general approach to reproducibility testing is needed"

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="35" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/12244)
<!-- Reviewable:end -->

python/servo/package_commands.py

@@ -16,7 +16,6 @@ sys.path.append(path.join(path.dirname(sys.argv[0]), "components", "style", "pro
 import os
 import shutil
 import subprocess
-import tarfile
 
 from mach.registrar import Registrar
 from datetime import datetime
@@ -29,7 +28,14 @@ from mach.decorators import (
 
 from mako.template import Template
 
-from servo.command_base import CommandBase, cd, BuildNotFound, is_macosx, is_windows
+from servo.command_base import (
+    archive_deterministically,
+    BuildNotFound,
+    cd,
+    CommandBase,
+    is_macosx,
+    is_windows,
+)
 from servo.post_build_commands import find_dep_path_newest
 
 
@@ -205,7 +211,10 @@ class PackageCommands(CommandBase):
         else:
             dir_to_package = '/'.join(binary_path.split('/')[:-1])
             dir_to_root = '/'.join(binary_path.split('/')[:-3])
-            shutil.copytree(dir_to_root + '/resources', dir_to_package + '/resources')
+            resources_dir = dir_to_package + '/resources'
+            if os.path.exists(resources_dir):
+                delete(resources_dir)
+            shutil.copytree(dir_to_root + '/resources', resources_dir)
             browserhtml_path = find_dep_path_newest('browserhtml', binary_path)
             if browserhtml_path is None:
                 print("Could not find browserhtml package; perhaps you haven't built Servo.")
@@ -234,9 +243,9 @@ class PackageCommands(CommandBase):
             time = datetime.utcnow().replace(microsecond=0).isoformat()
             time = time.replace(':', "-")
             tar_path += time + "-servo-tech-demo.tar.gz"
-            with tarfile.open(tar_path, "w:gz") as tar:
-                # arcname is to add by relative rather than absolute path
-                tar.add(dir_to_package, arcname='servo/')
+
+            archive_deterministically(dir_to_package, tar_path, prepend_path='servo/')
+
             print("Packaged Servo into " + tar_path)
 
     @Command('install',