Add opt-in support for the commit-msg hook

docs/man.rst

@@ -126,6 +126,13 @@ Configuration is managed by :manpage:`git-config(1)`.
    is specified. Overridden by :option:`--no-autosquash`. Defaults to false. If
    not set, the value of ``rebase.autoSquash`` is used instead.
 
+.. gitconfig:: revise.run-hooks.commit-msg
+
+   If set to true the **commit-msg** hook will be run after exiting the
+   editor. Defaults to false, because (unlike with :manpage:`git-rebase(1)`)
+   the worktree state might not reflect the commit state. If the hook takes
+   the worktree state into account, it might behave differently.
+
 
 CONFLICT RESOLUTION
 ===================

git-revise.1

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "GIT-REVISE" "1" "Jun 07, 2020" "0.6.0" "git-revise"
+.TH "GIT-REVISE" "1" "May 04, 2021" "0.6.0" "git-revise"
 .SH NAME
 git-revise \- Efficiently update, split, and rearrange git commits
 .
@@ -147,6 +147,14 @@ If set to true, imply \fI\%\-\-autosquash\fP whenever \fI\%\-\-interactive\fP
 is specified. Overridden by \fI\%\-\-no\-autosquash\fP\&. Defaults to false. If
 not set, the value of \fBrebase.autoSquash\fP is used instead.
 .UNINDENT
+.INDENT 0.0
+.TP
+.B revise.run\-hooks.commit\-msg
+If set to true the \fBcommit\-msg\fP hook will be run after exiting the
+editor. Defaults to false, because (unlike with \fBgit\-rebase(1)\fP)
+the worktree state might not reflect the commit state. If the hook takes
+the worktree state into account, it might behave differently.
+.UNINDENT
 .SH CONFLICT RESOLUTION
 .sp
 When a conflict is encountered, \fBgit revise\fP will attempt to resolve

gitrevise/tui.py

@@ -6,6 +6,7 @@
 from .odb import Repository, Commit, Reference
 from .utils import (
     EditorError,
+    HookError,
     commit_range,
     edit_commit_message,
     update_head,
@@ -217,14 +218,20 @@ def main(argv: Optional[List[str]] = None) -> None:
         with Repository() as repo:
             inner_main(args, repo)
     except CalledProcessError as err:
-        print(f"subprocess exited with non-zero status: {err.returncode}")
+        if err.returncode != 0:
+            print(f"subprocess exited with non-zero status: {err.returncode}")
+        else:
+            print(f"subprocess error: {err}")
         sys.exit(1)
     except EditorError as err:
         print(f"editor error: {err}")
         sys.exit(1)
     except MergeConflict as err:
         print(f"merge conflict: {err}")
         sys.exit(1)
+    except HookError as err:
+        print(f"{err} hook declined")
+        sys.exit(1)
     except ValueError as err:
         print(f"invalid value: {err}")
         sys.exit(1)

gitrevise/utils.py

@@ -1,4 +1,4 @@
-from typing import List, Optional, Tuple
+from typing import Callable, List, Optional, Tuple
 from subprocess import run, CalledProcessError
 from pathlib import Path
 import textwrap
@@ -14,6 +14,10 @@ class EditorError(Exception):
     pass
 
 
+class HookError(Exception):
+    pass
+
+
 def commit_range(base: Commit, tip: Commit) -> List[Commit]:
     """Oldest-first iterator over the given commit range,
     not including the commit ``base``"""
@@ -57,7 +61,9 @@ def local_commits(repo: Repository, tip: Commit) -> Tuple[Commit, List[Commit]]:
     return base, commits
 
 
-def edit_file_with_editor(editor: str, path: Path) -> bytes:
+def edit_file_with_editor(
+    editor: str, path: Path, post_fn: Optional[Callable[[Path], None]] = None
+) -> bytes:
     try:
         if os.name == "nt":
             # The popular "Git for Windows" distribution uses a bundled msys
@@ -71,6 +77,10 @@ def edit_file_with_editor(editor: str, path: Path) -> bytes:
         run(cmd, check=True, cwd=path.parent)
     except CalledProcessError as err:
         raise EditorError(f"Editor exited with status {err}") from err
+
+    if post_fn:
+        post_fn(path)
+
     return path.read_bytes()
 
 
@@ -127,6 +137,7 @@ def run_specific_editor(
     comments: Optional[str] = None,
     allow_empty: bool = False,
     allow_whitespace_before_comments: bool = False,
+    post_fn: Optional[Callable[[Path], None]] = None,
 ) -> bytes:
     """Run the editor configured for git to edit the given text"""
     path = repo.get_tempdir() / filename
@@ -144,7 +155,7 @@ def run_specific_editor(
                 handle.write(b"\n")
 
     # Invoke the editor
-    data = edit_file_with_editor(editor, path)
+    data = edit_file_with_editor(editor, path, post_fn)
     if comments:
         data = strip_comments(
             data,
@@ -172,6 +183,7 @@ def run_editor(
     text: bytes,
     comments: Optional[str] = None,
     allow_empty: bool = False,
+    post_fn: Optional[Callable[[Path], None]] = None,
 ) -> bytes:
     """Run the editor configured for git to edit the given text"""
     return run_specific_editor(
@@ -181,6 +193,7 @@ def run_editor(
         text=text,
         comments=comments,
         allow_empty=allow_empty,
+        post_fn=post_fn,
     )
 
 
@@ -215,6 +228,31 @@ def run_sequence_editor(
     )
 
 
+def create_commit_msg_caller(repo: Repository) -> Optional[Callable[[Path], None]]:
+    """Return a function which calls the "commit-msg" hook if it is
+    present"""
+
+    hooks_path = repo.config("core.hooksPath", b"")
+
+    if not hooks_path:
+        commit_msg_hook = os.path.join(
+            repo.git("rev-parse", "--git-common-dir"), b"hooks/commit-msg"
+        )
+    else:
+        commit_msg_hook = os.path.join(hooks_path, b"commit-msg")
+
+    def run_commit_msg(filepath: Path) -> None:
+        # If the hook script is present but not executable git would warn
+        # (unless `git config advice.ignoredHook false` is set), but git-revise
+        # silently ignores that file.
+        if os.access(commit_msg_hook, os.X_OK):
+            # stderr/stdout of the hook are passed through
+            if run([commit_msg_hook, filepath]).returncode != 0:
+                raise HookError("commit-msg")
+
+    return run_commit_msg
+
+
 def edit_commit_message(commit: Commit) -> Commit:
     """Launch an editor to edit the commit message of ``commit``, returning
     a modified commit"""
@@ -231,7 +269,19 @@ def edit_commit_message(commit: Commit) -> Commit:
         tree_b = commit.tree().persist().hex()
         comments += "\n" + repo.git("diff-tree", "--stat", tree_a, tree_b).decode()
 
-    message = run_editor(repo, "COMMIT_EDITMSG", commit.message, comments=comments)
+    if repo.bool_config("revise.run-hooks.commit-msg", default=False):
+        hook = create_commit_msg_caller(commit.repo)
+    else:
+        hook = None
+
+    message = run_editor(
+        repo,
+        "COMMIT_EDITMSG",
+        commit.message,
+        comments=comments,
+        post_fn=hook,
+    )
+
     return commit.update(message=message)