Improve detection of squash commits

RELEASE_NOTES.md

@@ -6,6 +6,7 @@
 - fixed: `push=no` and `slide-out=no` qualifiers now work in `git machete advance` now
 - fixed: `rebase=no` qualifier now works in `git machete slide-out`
 - improved: in `git machete github create-pr`/`gitlab create-mr`, check whether base/target branch for PR/MR exists in remote, instead of fetching the entire remote
+- fixed: better detection of squash merges and rebases when there are commits between the fork point and the merge/rebase. Option controlled by argument `--squash-merge-detection` and config key `machete.squashMergeDetection` (contributed by @gjulianm)
 
 ## New in git-machete 3.25.2
 

docs/man/git-machete.1

@@ -27,7 +27,7 @@ level margin: \\n[rst2man-indent\\n[rst2man-indent-level]]
 .\" new: \\n[rst2man-indent\\n[rst2man-indent-level]]
 .in \\n[rst2man-indent\\n[rst2man-indent-level]]u
 ..
-.TH "GIT-MACHETE" "1" "May 08, 2024" "" "git-machete"
+.TH "GIT-MACHETE" "1" "May 20, 2024" "" "git-machete"
 .SH NAME
 git-machete \- git-machete 3.25.3
 .sp
@@ -459,6 +459,12 @@ for both regular directory and worktree.
 .sp
 If you want the worktree to have its own branch layout file (located under \fB\&.git/worktrees/.../machete\fP),
 set \fBgit config machete.worktree.useTopLevelMacheteFile false\fP\&.
+.TP
+.B \fBmachete.squashMergeDetection\fP:
+Controls the algorithm used to detect squash merges. Possible values are:
+* \fBnone\fP: No squash merge/rebase detection.
+* \fBsimple\fP: Compares the tree state of the merge commit with the tree state of the upstream branch. This detects squash merges/rebases as long as there was not any commit on the upstream branch since the last common commit.
+* \fBexact\fP: Compares the patch that would be applied by the merge commit with the commits that ocurred on the upstream branch since the last common commit. This detects squash merges/rebases even if there were commits on the upstream branch since the last common commit. However, it might have a performance impact as it requires listing all the commits in the upstream.
 .UNINDENT
 .sp
 \fBEnvironment variables:\fP

docs/source/cli/config.rst

@@ -49,6 +49,12 @@ Note: ``config`` is not a command as such, just a help topic (there is no ``git
     If you want the worktree to have its own branch layout file (located under ``.git/worktrees/.../machete``),
     set ``git config machete.worktree.useTopLevelMacheteFile false``.
 
+``machete.squashMergeDetection``:
+    Controls the algorithm used to detect squash merges. Possible values are:
+    * ``none``: No squash merge/rebase detection.
+    * ``simple``: Compares the tree state of the merge commit with the tree state of the upstream branch. This detects squash merges/rebases as long as there was not any commit on the upstream branch since the last common commit.
+    * ``exact``: Compares the patch that would be applied by the merge commit with the commits that occurred on the upstream branch since the last common commit. This detects squash merges/rebases even if there were commits on the upstream branch since the last common commit. However, it might have a performance impact as it requires listing all the commits in the upstream.
+
 
 **Environment variables:**
 

git_machete/cli.py

@@ -10,6 +10,7 @@
 
 import git_machete.options
 from git_machete import __version__, git_config_keys, utils
+from git_machete.constants import SquashMergeDetection
 from git_machete.github import GitHubClient
 from git_machete.gitlab import GitLabClient
 
@@ -70,7 +71,7 @@ def get_help_description(display_help_topics: bool, command: Optional[str] = Non
             usage_str += underline(hdr) + '\n\n'
             for cm in cmds:
                 alias = f", {alias_by_command[cm]}" if cm in alias_by_command else ""
-                usage_str += f'    {bold(cm + alias) : <{18 if utils.ascii_only else 27}}{short_docs[cm]}'
+                usage_str += f'    {bold(cm + alias): <{18 if utils.ascii_only else 27}}{short_docs[cm]}'
                 usage_str += '\n'
             usage_str += '\n'
         usage_str += fmt(textwrap.dedent("""
@@ -364,6 +365,9 @@ def add_code_hosting_parser(command: str, subcommand_suffix: str, include_sync:
     status_parser.add_argument('-l', '--list-commits', action='store_true')
     status_parser.add_argument('-L', '--list-commits-with-hashes', action='store_true')
     status_parser.add_argument('--no-detect-squash-merges', action='store_true')
+    status_parser.add_argument('--squash-merge-detection',
+                               choices=list(SquashMergeDetection), default=None,
+                               type=SquashMergeDetection.from_string)
 
     traverse_parser = subparsers.add_parser(
         'traverse',
@@ -379,6 +383,9 @@ def add_code_hosting_parser(command: str, subcommand_suffix: str, include_sync:
     traverse_parser.add_argument('--no-edit-merge', action='store_true')
     traverse_parser.add_argument('--no-interactive-rebase', action='store_true')
     traverse_parser.add_argument('--no-detect-squash-merges', action='store_true')
+    traverse_parser.add_argument('--squash-merge-detection',
+                                 choices=list(SquashMergeDetection), default=None,
+                                 type=SquashMergeDetection.from_string)
     traverse_parser.add_argument('--push', action='store_true')
     traverse_parser.add_argument('--no-push', action='store_true')
     traverse_parser.add_argument('--push-untracked', action='store_true')
@@ -455,7 +462,10 @@ def update_cli_options_using_parsed_args(
         elif opt == "n":
             cli_opts.opt_n = True
         elif opt == "no_detect_squash_merges":
-            cli_opts.opt_no_detect_squash_merges = True
+            print("--no-detect-squash-merges is deprecated, use --squash-merge-detection=none")
+            cli_opts.opt_squash_merge_detection = SquashMergeDetection.NONE
+        elif opt == "squash_merge_detection" and arg is not None:  # If the value is None it means the user did not provide any value
+            cli_opts.opt_squash_merge_detection = arg  # Already a SquashMergeDetection enum
         elif opt == "no_edit_merge":
             cli_opts.opt_no_edit_merge = True
         elif opt == "no_interactive_rebase":
@@ -529,6 +539,10 @@ def update_cli_options_using_config_keys(
         else:
             cli_opts.opt_push_tracked, cli_opts.opt_push_untracked = False, False
 
+    squash_merge_detection = git.get_config_attr_or_none(key=git_config_keys.SQUASH_MERGE_DETECTION)
+    if squash_merge_detection is not None:
+        cli_opts.opt_squash_merge_detection = SquashMergeDetection.from_string(squash_merge_detection)
+
 
 def set_utils_global_variables(parsed_args: argparse.Namespace) -> None:
     args = vars(parsed_args)
@@ -867,7 +881,7 @@ def strip_remote_name(remote_branch: RemoteBranchShortName) -> LocalBranchShortN
                 warn_when_branch_in_sync_but_fork_point_off=True,
                 opt_list_commits=cli_opts.opt_list_commits,
                 opt_list_commits_with_hashes=cli_opts.opt_list_commits_with_hashes,
-                opt_no_detect_squash_merges=cli_opts.opt_no_detect_squash_merges)
+                opt_squash_merge_detection=cli_opts.opt_squash_merge_detection)
         elif cmd in {"traverse", alias_by_command["traverse"]}:
             if cli_opts.opt_start_from not in {"here", "root", "first-root"}:
                 raise MacheteException(
@@ -883,7 +897,7 @@ def strip_remote_name(remote_branch: RemoteBranchShortName) -> LocalBranchShortN
                 opt_fetch=cli_opts.opt_fetch,
                 opt_list_commits=cli_opts.opt_list_commits,
                 opt_merge=cli_opts.opt_merge,
-                opt_no_detect_squash_merges=cli_opts.opt_no_detect_squash_merges,
+                opt_squash_merge_detection=cli_opts.opt_squash_merge_detection,
                 opt_no_edit_merge=cli_opts.opt_no_edit_merge,
                 opt_no_interactive_rebase=cli_opts.opt_no_interactive_rebase,
                 opt_push_tracked=cli_opts.opt_push_tracked,

git_machete/client.py

@@ -17,7 +17,7 @@
                            is_matching_remote_url)
 from .constants import (DISCOVER_DEFAULT_FRESH_BRANCH_COUNT, PICK_FIRST_ROOT,
                         PICK_LAST_ROOT, GitFormatPatterns,
-                        SyncToRemoteStatuses)
+                        SquashMergeDetection, SyncToRemoteStatuses)
 from .exceptions import (InteractionStopped, MacheteException,
                          UnexpectedMacheteException)
 from .git_operations import (HEAD, AnyBranchName, AnyRevision, BranchPair,
@@ -463,7 +463,7 @@ def get_root_of(branch: LocalBranchShortName) -> LocalBranchShortName:
                 if self.is_merged_to(
                         branch=branch,
                         upstream=upstream,
-                        opt_no_detect_squash_merges=False
+                        opt_squash_merge_detection=SquashMergeDetection.NONE
                 ):
                     debug(f"inferred upstream of {branch} is {upstream}, but "
                           f"{branch} is merged to {upstream}; skipping {branch} from discovered tree")
@@ -489,7 +489,7 @@ def get_root_of(branch: LocalBranchShortName) -> LocalBranchShortName:
             warn_when_branch_in_sync_but_fork_point_off=False,
             opt_list_commits=opt_list_commits,
             opt_list_commits_with_hashes=False,
-            opt_no_detect_squash_merges=False)
+            opt_squash_merge_detection=SquashMergeDetection.NONE)
         print("")
         do_backup = os.path.isfile(self.__branch_layout_file_path) and io.open(self.__branch_layout_file_path).read().strip()
         backup_msg = (
@@ -611,7 +611,7 @@ def advance(self, *, branch: LocalBranchShortName, opt_yes: bool) -> None:
 
         def connected_with_green_edge(bd: LocalBranchShortName) -> bool:
             return bool(
-                not self.__is_merged_to_upstream(bd, opt_no_detect_squash_merges=False) and
+                not self.__is_merged_to_upstream(bd, opt_squash_merge_detection=SquashMergeDetection.NONE) and
                 self.__git.is_ancestor_or_equal(branch.full_name(), bd.full_name()) and
                 (self.__get_overridden_fork_point(bd) or
                  self.__git.get_commit_hash_by_revision(branch) == self.fork_point(bd, use_overrides=False)))
@@ -685,7 +685,7 @@ def traverse(
             opt_fetch: bool,
             opt_list_commits: bool,
             opt_merge: bool,
-            opt_no_detect_squash_merges: bool,
+            opt_squash_merge_detection: SquashMergeDetection,
             opt_no_edit_merge: bool,
             opt_no_interactive_rebase: bool,
             opt_push_tracked: bool,
@@ -730,7 +730,7 @@ def traverse(
             upstream = self.__up_branch.get(branch)
 
             needs_slide_out: bool = self.__is_merged_to_upstream(
-                branch, opt_no_detect_squash_merges=opt_no_detect_squash_merges)
+                branch, opt_squash_merge_detection=opt_squash_merge_detection)
             if needs_slide_out and branch in self.annotations:
                 needs_slide_out = self.annotations[branch].qualifiers.slide_out
             s, remote = self.__git.get_combined_remote_sync_status(branch)
@@ -785,7 +785,7 @@ def traverse(
                     warn_when_branch_in_sync_but_fork_point_off=True,
                     opt_list_commits=opt_list_commits,
                     opt_list_commits_with_hashes=False,
-                    opt_no_detect_squash_merges=opt_no_detect_squash_merges)
+                    opt_squash_merge_detection=opt_squash_merge_detection)
                 self.__print_new_line(True)
             if needs_slide_out:
                 any_action_suggested = True
@@ -944,7 +944,7 @@ def traverse(
             warn_when_branch_in_sync_but_fork_point_off=True,
             opt_list_commits=opt_list_commits,
             opt_list_commits_with_hashes=False,
-            opt_no_detect_squash_merges=opt_no_detect_squash_merges)
+            opt_squash_merge_detection=opt_squash_merge_detection)
         print("")
         if current_branch == self.managed_branches[-1]:
             msg: str = f"Reached branch {bold(current_branch)} which has no successor"
@@ -969,7 +969,7 @@ def status(
             warn_when_branch_in_sync_but_fork_point_off: bool,
             opt_list_commits: bool,
             opt_list_commits_with_hashes: bool,
-            opt_no_detect_squash_merges: bool
+            opt_squash_merge_detection: SquashMergeDetection
     ) -> None:
         next_sibling_of_ancestor_by_branch: OrderedDict[LocalBranchShortName, List[Optional[LocalBranchShortName]]] = OrderedDict()
 
@@ -1009,7 +1009,7 @@ def fork_point_hash(branch_: LocalBranchShortName) -> Optional[FullCommitHash]:
             if self.is_merged_to(
                     branch=branch,
                     upstream=parent_branch,
-                    opt_no_detect_squash_merges=opt_no_detect_squash_merges):
+                    opt_squash_merge_detection=opt_squash_merge_detection):
                 sync_to_parent_status[branch] = SyncToParentStatus.MergedToParent
             elif not self.__git.is_ancestor_or_equal(parent_branch.full_name(), branch.full_name()):
                 sync_to_parent_status[branch] = SyncToParentStatus.OutOfSync
@@ -1065,8 +1065,8 @@ def print_line_prefix(branch_: LocalBranchShortName, suffix: str) -> None:
                             right_arrow = colored(utils.get_right_arrow(), AnsiEscapeCodes.RED)
                             fork_point_str = colored("fork point ???", AnsiEscapeCodes.RED)
                             fp_suffix: str = f' {right_arrow} {fork_point_str} ' + \
-                                             ("this commit" if opt_list_commits_with_hashes else f"commit {commit.short_hash}") + \
-                                             f' seems to be a part of the unique history of {fp_branches_formatted}'
+                                ("this commit" if opt_list_commits_with_hashes else f"commit {commit.short_hash}") + \
+                                f' seems to be a part of the unique history of {fp_branches_formatted}'
                         else:
                             fp_suffix = ''
                         print_line_prefix(branch, utils.get_vertical_bar())
@@ -1159,7 +1159,7 @@ def print_line_prefix(branch_: LocalBranchShortName, suffix: str) -> None:
             else:
                 affected_branches = ", ".join(map(bold, branches_in_sync_but_fork_point_off))
                 first_part = f"yellow edges indicate that fork points for {affected_branches} are probably incorrectly inferred,\n" \
-                             "or that some extra branch should be added between each of these branches and its parent"
+                    "or that some extra branch should be added between each of these branches and its parent"
 
             if not opt_list_commits:
                 second_part = "Run `git machete status --list-commits` or " \
@@ -1527,11 +1527,11 @@ def get_slidable_after(self, branch: LocalBranchShortName) -> List[LocalBranchSh
         return []
 
     def __is_merged_to_upstream(
-            self, branch: LocalBranchShortName, *, opt_no_detect_squash_merges: bool) -> bool:
+            self, branch: LocalBranchShortName, *, opt_squash_merge_detection: SquashMergeDetection) -> bool:
         upstream = self.__up_branch.get(branch)
         if not upstream:
             return False
-        return self.is_merged_to(branch, upstream, opt_no_detect_squash_merges=opt_no_detect_squash_merges)
+        return self.is_merged_to(branch, upstream, opt_squash_merge_detection=opt_squash_merge_detection)
 
     def __run_post_slide_out_hook(self, new_upstream: LocalBranchShortName, slid_out_branch: LocalBranchShortName,
                                   new_downstreams: List[LocalBranchShortName]) -> None:
@@ -1867,10 +1867,10 @@ def __pick_remote(
         rems = self.__git.get_remotes()
         print("\n".join(f"[{index + 1}] {rem}" for index, rem in enumerate(rems)))
         msg = f"Select number 1..{len(rems)} to specify the destination remote " \
-              "repository, or 'n' to skip this branch, or " \
-              "'q' to quit the traverse: " if is_called_from_traverse \
+            "repository, or 'n' to skip this branch, or " \
+            "'q' to quit the traverse: " if is_called_from_traverse \
             else f"Select number 1..{len(rems)} to specify the destination remote " \
-                 "repository, or 'q' to quit the operation: "
+            "repository, or 'q' to quit the operation: "
 
         ans = input(msg).lower()
         if ans in ('q', 'quit'):
@@ -2012,7 +2012,12 @@ def __handle_untracked_branch(
         elif ans in ('q', 'quit'):
             raise InteractionStopped
 
-    def is_merged_to(self, branch: LocalBranchShortName, upstream: AnyBranchName, *, opt_no_detect_squash_merges: bool) -> bool:
+    def is_merged_to(
+            self,
+            branch: LocalBranchShortName,
+            upstream: AnyBranchName,
+            opt_squash_merge_detection: SquashMergeDetection
+    ) -> bool:
         if self.__git.is_ancestor_or_equal(branch.full_name(), upstream.full_name()):
             # If branch is ancestor of or equal to the upstream, we need to distinguish between the
             # case of branch being "recently" created from the upstream and the case of
@@ -2021,13 +2026,13 @@ def is_merged_to(self, branch: LocalBranchShortName, upstream: AnyBranchName, *,
             # (reflog stripped of trivial events like branch creation, reset etc.)
             # is non-empty.
             return bool(self.filtered_reflog(branch))
-        elif opt_no_detect_squash_merges:
+        elif opt_squash_merge_detection == SquashMergeDetection.NONE:
             return False
         else:
             # In the default mode.
             # If a commit with an identical tree state to branch is reachable from upstream,
             # then branch may have been squashed or rebase-merged into upstream.
-            return self.__git.is_equivalent_tree_reachable(branch, upstream)
+            return self.__git.is_equivalent_tree_reachable(branch, upstream, opt_squash_merge_detection=opt_squash_merge_detection)
 
     @staticmethod
     def ask_if(
@@ -2321,7 +2326,7 @@ def restack_pull_request(self, spec: CodeHostingSpec) -> None:
                     warn_when_branch_in_sync_but_fork_point_off=True,
                     opt_list_commits=False,
                     opt_list_commits_with_hashes=False,
-                    opt_no_detect_squash_merges=False)
+                    opt_squash_merge_detection=SquashMergeDetection.NONE)
                 self.__print_new_line(False)
 
                 if converted_to_draft:
@@ -2855,7 +2860,7 @@ def __sync_before_creating_pr(self, spec: CodeHostingSpec, *, opt_onto: Optional
                     warn_when_branch_in_sync_but_fork_point_off=True,
                     opt_list_commits=False,
                     opt_list_commits_with_hashes=False,
-                    opt_no_detect_squash_merges=False)
+                    opt_squash_merge_detection=SquashMergeDetection.NONE)
                 self.__print_new_line(False)
 
         else:

git_machete/constants.py

@@ -2,6 +2,7 @@
 
 MAX_COUNT_FOR_INITIAL_LOG = 10
 DISCOVER_DEFAULT_FRESH_BRANCH_COUNT = 10
+MAX_COMMITS_FOR_SQUASH_MERGE_DETECTION = 1000
 
 PICK_FIRST_ROOT: int = 0
 PICK_LAST_ROOT: int = -1
@@ -27,3 +28,19 @@ class GitFormatPatterns(Enum):
     FULL_MESSAGE = "%B"
     # subject NOT included
     MESSAGE_BODY = "%b"
+
+
+class SquashMergeDetection(Enum):
+    NONE = "none"
+    SIMPLE = "simple"
+    EXACT = "exact"
+
+    @staticmethod
+    def from_string(value: str) -> 'SquashMergeDetection':
+        if value == "none":
+            return SquashMergeDetection.NONE
+        if value == "simple":
+            return SquashMergeDetection.SIMPLE
+        if value == "exact":
+            return SquashMergeDetection.EXACT
+        raise ValueError(f"Unknown value '{value}' for SquashMergeDetection")