Add script to pre-process raw release notes (#1380)

Summary: This commit adds a helper script to pre-process
the raw release notes produced by github. This script produces
a template with the standard sections and pre-sorts all commits
into categories based on github labels and keywords in the
commit titles.

```
python scripts/clean_release_notes.py raw_release_notes.txt
```

Test Plan: Manual testing on v0.7.0 release notes

scripts/clean_release_notes.py

@@ -0,0 +1,225 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+
+# This source code is licensed under the license found in the
+# LICENSE file in the root directory of this source tree.
+
+# =============================================================
+#  This script automatically cleans up the raw release notes
+#  generated by github by doing an initial pass to sort the
+#  commits. The output still requires manual reviewing.
+#
+#  This script uses PyGithub. If you don't have it yet, please
+#  install it using:
+#
+#    pip install PyGithub
+#
+#  We expect the following format for the input release notes:
+#
+#    ## What's Changed
+#    * commit1_title by @userX in https://github.com/pytorch/ao/pull/123
+#    * commit2_title by @userY in https://github.com/pytorch/ao/pull/234
+#    * commit3_title by @userZ in https://github.com/pytorch/ao/pull/345
+#
+#    ## New Contributors
+#    * @userX made their first contribution in https://github.com/pytorch/ao/pull/123
+#    * @userY made their first contribution in https://github.com/pytorch/ao/pull/234
+#
+#  Example output:
+#
+#    ## Highlights
+#
+#    We are excited to announce the X.Y.Z release of torchao! This release adds support for A, B, C, D!
+#
+#    ### Highlight Feature 1
+#
+#    ### Highlight Feature 2
+#
+#    ## BC-Breaking
+#
+#    ## Deprecation
+#
+#    ## New Features
+#    * commit1_title (https://github.com/pytorch/ao/pull/123)
+#
+#    ## Improvement
+#    * commit2_title (https://github.com/pytorch/ao/pull/234)
+#
+#    ## Bug Fixes
+#    * commit3_title (https://github.com/pytorch/ao/pull/345)
+#
+#    ## Performance
+#
+#    ## Documentation
+#
+#    ## Developers
+#
+#    ## New Contributors
+#    * @userX made their first contribution in https://github.com/pytorch/ao/pull/123
+#    * @userY made their first contribution in https://github.com/pytorch/ao/pull/234
+#
+# =============================================================
+
+
+import os
+import re
+import sys
+from typing import Dict, List, Optional
+
+try:
+    from github import Github
+except ImportError as err:
+    raise ValueError("PyGithub not installed, please run 'pip install PyGithub'") from err
+
+if len(sys.argv) != 2:
+    print("Usage: python clean_release_notes.py [raw_release_notes.txt]")
+    sys.exit(1)
+
+input_file = sys.argv[1]
+output_file = input_file + ".out"
+VERBOSE = os.getenv("VERBOSE", "true").lower() == "true"
+GITHUB_LABEL_TO_CATEGORY = {
+    "topic: bc-breaking": "BC Breaking",
+    "topic: deprecation": "Deprecation",
+    "topic: new feature": "New Features",
+    "topic: improvement": "Improvement",
+    "topic: bug fix": "Bug Fixes",
+    "topic: performance": "Performance",
+    "topic: documentation": "Documentation",
+    "topic: for developer": "Developers",
+}
+
+
+def clean_release_notes():
+    """
+    Main entry point for this script.
+
+    This function pre-processes the raw release notes and produces a template
+    with all the standard sections and pre-sorts the commits into different
+    categories based on github labels and commit title keywords.
+    """
+
+    # Write the header section
+    with open(output_file, "w") as out_f:
+        out_f.write("## Highlights\n\n")
+        out_f.write("We are excited to announce the X.Y.Z release of torchao! This release adds support for A, B, C, D!\n\n")
+        out_f.write("### Highlight Feature 1\n\n")
+        out_f.write("### Highlight Feature 2\n\n")
+
+    # Sort commits into different categories and write them to output file
+    # For lines after the commits, just copy them to the output file as is
+    commit_lines = []
+    commit_start = False
+    commits_by_category = {
+        "BC Breaking": [],
+        "Deprecations": [],
+        "New Features": [],
+        "Improvement": [],
+        "Bug Fixes": [],
+        "Performance": [],
+        "Documentation": [],
+        "Developers": [],
+    }
+    with open(input_file, "r") as in_f, open(output_file, "a") as out_f:
+        for line in in_f.readlines():
+            if line.startswith("## What's Changed"):
+                commit_start = True
+            elif commit_start and line.startswith("*"):
+                commit_lines.append(line)
+            elif commit_start:
+                # End of commits, fetch PR labels based on commits collected so far
+                commit_start = False
+                pr_number_to_label = fetch_pr_labels(commit_lines)
+                # Assign each commit to a category
+                for commit_line in commit_lines:
+                    category = get_commit_category(commit_line, pr_number_to_label)
+                    if category is not None:
+                        commits_by_category[category].append(commit_line)
+                # Write all commits to the output file by category
+                for category, commits in commits_by_category.items():
+                    out_f.write("## %s\n\n" % category)
+                    for commit_line in commits:
+                        out_f.write(format_commit(commit_line))
+                    out_f.write("\n")
+            else:
+                # Not a commit, just copy to the output file
+                out_f.write(line)
+    print("Wrote to %s." % output_file)
+
+
+def parse_pr_number(commit_line: str) -> int:
+    """
+    Helper function to parse PR number from commit line.
+    """
+    return int(re.match(".*pytorch/ao/pull/(.*)", commit_line).groups()[0])
+
+
+def fetch_pr_labels(commit_lines: List[str]) -> Dict[int, str]:
+    """
+    Fetch the relevant github labels starting with "topic: " from all PRs.
+    If such a label exists for a given PR, store the first one.
+    """
+    pr_number_to_label = {}
+    all_pr_numbers = [parse_pr_number(line) for line in commit_lines]
+    smallest_pr_number = min(all_pr_numbers)
+    repo = Github().get_repo("pytorch/ao")
+
+    # This call fetches 30 PRs at a time in descending order of when the PR was created
+    pulls = repo.get_pulls(state="closed")
+    for pr in pulls:
+        if pr.number < smallest_pr_number:
+            break
+        labels = [l.name for l in pr.labels if l.name.startswith("topic: ")]
+        if len(labels) > 0:
+            if VERBOSE:
+                print("Found label for PR %s: '%s'" % (pr.number, labels[0]))
+            pr_number_to_label[pr.number] = labels[0]
+    return pr_number_to_label
+
+
+def get_commit_category(commit_line: str, pr_number_to_label: Dict[int, str]) -> Optional[str]:
+    """
+    Assign the commit to a category based on:
+      (1) The github label if it exists
+      (2) Keywords in the PR title
+
+    If the commit is not meant to be user facing, remove None.
+    Otherwise, return "Improvement" by default.
+    """
+    pr_number = parse_pr_number(commit_line)
+    if pr_number in pr_number_to_label:
+        label = pr_number_to_label[pr_number]
+        if label == "topic: not user facing":
+            return None
+        if label in GITHUB_LABEL_TO_CATEGORY:
+            return GITHUB_LABEL_TO_CATEGORY[label]
+    elif any(x in commit_line.lower() for x in ["revert", "version.txt"]):
+        return None
+    elif any(x in commit_line.lower() for x in ["doc", "readme", "tutorial", "typo", "example", "spelling"]):
+        return "Documentation"
+    elif any(x in commit_line.lower() for x in ["test", "lint", " ci", "nightl"]):
+        return "Developers"
+    elif " fix" in commit_line.lower():
+        return "Bug Fixes"
+    elif " add" in commit_line.lower():
+        return "New Features"
+    else:
+        return "Improvement"
+
+
+def format_commit(commit_line: str) -> str:
+    """
+    Format the commit line as follows:
+      Before: * commit title by @userX in https://github.com/pytorch/ao/pull/123
+      After:  * Commit title (https://github.com/pytorch/ao/pull/123)
+    """
+    # Remove author, put PR link in parentheses
+    commit_line = re.sub(" by @.* in (.*)", " (\g<1>)", commit_line)
+    # Capitalize first letter
+    commit_line = commit_line.lstrip("* ")
+    commit_line = "* " + commit_line[0].upper() + commit_line[1:]
+    return commit_line
+
+
+if __name__ == "__main__":
+    clean_release_notes()