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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::collections::HashSet;
use std::fmt::{self, Debug, Display};
use std::num;
use std::result::Result;
use chrono::{DateTime, Utc};
use git_workarea::{
CommitId, Conflict, GitContext, GitError, Identity, MergeResult, MergeStatus, WorkAreaError,
};
use log::{debug, info, warn};
use thiserror::Error;
/// Why a commit is not a valid staging branch commit.
///
/// The staging branch format is such that its first-parent history consists solely of two-parent
/// merge commits. It must also have the base commit as an ancestor.
#[derive(Debug, PartialEq, Eq)]
#[non_exhaustive]
pub enum InvalidCommitReason {
/// A non-merge commit was found.
NonMergeCommit,
/// An octopus merge commit was found.
OctopusMerge,
/// The integration branch is not related to the base.
NotRelated,
/// The integration branch does not point to a commit.
NotACommit,
/// A merge commit has an invalid commit subject.
InvalidSubject(String),
/// A merge commit is missing an ID.
MissingId,
/// A merge commit is missing a URL.
MissingUrl,
/// A topic has in ID of `0`, which is reserved for the base branch.
ZeroId,
/// A topic has in ID that is not an unsigned integer.
UnparseableId(String),
}
impl Display for InvalidCommitReason {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
let reason = match self {
InvalidCommitReason::NonMergeCommit => "non-merge commit",
InvalidCommitReason::OctopusMerge => "octopus merge",
InvalidCommitReason::NotRelated => "not related",
InvalidCommitReason::NotACommit => "not a commit",
InvalidCommitReason::InvalidSubject(_) => "invalid subject",
InvalidCommitReason::MissingId => "missing id",
InvalidCommitReason::MissingUrl => "missing url",
InvalidCommitReason::ZeroId => "invalid id (0)",
InvalidCommitReason::UnparseableId(_) => "unparseable id",
};
write!(f, "{}", reason)
}
}
/// Errors which may occur while managing a topic stage branch.
///
/// This enum is `non_exhaustive`, but cannot be marked as such until it is stable. In the
/// meantime, there is a hidden variant.
#[derive(Debug, Error)]
#[non_exhaustive]
pub enum StagerError {
/// An error occurred when working with Git itself.
#[error("git error: {}", source)]
Git {
/// The cause of the error.
#[from]
source: GitError,
},
/// An error occurred when working with the workarea.
#[error("workarea error: {}", source)]
WorkArea {
/// The cause of the error.
#[from]
source: WorkAreaError,
},
/// The integration branch is invalid.
#[error("invalid integration branch: {}: {}", commit, reason)]
InvalidIntegrationBranch {
/// The merge commit into the integration branch.
commit: CommitId,
/// Why the branch is invalid.
reason: InvalidCommitReason,
},
/// A topic with the given ID is already on the stage.
#[error("duplicate stage id: {}", id)]
DuplicateTopicId {
/// The topic ID which has duplicate merges.
id: u64,
},
/// An error occurred when creating a stage ref.
#[error("failed to update the {} ref to {}: {}", stage, base, output)]
CreateStageRef {
/// The ref that could not be made.
stage: CommitId,
/// What it should have been updated to.
base: CommitId,
/// Git's error output.
output: String,
},
/// An error occurred when listing the stage's history.
#[error(
"failed to list the first parent history of the stage branch: {}",
output
)]
ListStageHistory {
/// Git's error output.
output: String,
},
/// An error occurred when extracting topic information from a merge.
#[error(
"failed to get information about a merge on the topic stage: {}",
output
)]
ExtractMergeInfo {
/// Git's error output.
output: String,
},
/// An invalid merge into the stage was found.
#[error("invalid stage merge commit {} found: {}", commit, log_info)]
InvalidStageMerge {
/// The invalid merge commit.
commit: CommitId,
/// The log information extracted from the commit.
log_info: String,
},
/// The base commit cannot be unstaged.
#[error("cannot unstage base")]
CannotUnstageBase,
/// An invalid commit date was found.
#[error("failed to parse date: {}", source)]
DateParse {
/// The date parse error.
#[source]
source: chrono::ParseError,
},
/// An invalid topic ID was found.
#[deprecated(since = "4.1.0", note = "No longer used.")]
#[error("failed to parse topic ID: {}", source)]
IdParse {
/// The integer parse error.
#[source]
source: num::ParseIntError,
},
}
impl StagerError {
fn invalid_branch(commit: CommitId, reason: InvalidCommitReason) -> Self {
StagerError::InvalidIntegrationBranch {
commit,
reason,
}
}
fn duplicate_topic_id(id: u64) -> Self {
StagerError::DuplicateTopicId {
id,
}
}
fn create_stage_ref(stage: CommitId, base: CommitId, output: &[u8]) -> Self {
StagerError::CreateStageRef {
stage,
base,
output: String::from_utf8_lossy(output).into(),
}
}
fn list_stage_history(output: &[u8]) -> Self {
StagerError::ListStageHistory {
output: String::from_utf8_lossy(output).into(),
}
}
fn extract_merge_info(output: &[u8]) -> Self {
StagerError::ExtractMergeInfo {
output: String::from_utf8_lossy(output).into(),
}
}
fn invalid_stage_merge(commit: &str, log_info: &[u8]) -> Self {
StagerError::InvalidStageMerge {
commit: CommitId::new(commit),
log_info: String::from_utf8_lossy(log_info).into(),
}
}
fn date_parse(source: chrono::ParseError) -> Self {
StagerError::DateParse {
source,
}
}
}
type StagerResult<T> = Result<T, StagerError>;
/// A branch for the stager.
///
/// Topics contain additional information so that they may be easily identified and so that the
/// commit messages are useful to humans as well.
#[derive(Debug, Clone)]
pub struct Topic {
/// The `HEAD` commit of the topic branch.
pub commit: CommitId,
/// The author of the stage request.
pub author: Identity,
/// When the stage request occurred.
pub stamp: DateTime<Utc>,
/// An ID for the topic.
pub id: u64,
/// The name of the topic.
pub name: String,
/// The URL of the topic.
pub url: String,
}
impl Topic {
/// Create a topic.
///
/// The ID must be unique across all topics.
pub fn new<N, U>(
commit: CommitId,
author: Identity,
stamp: DateTime<Utc>,
id: u64,
name: N,
url: U,
) -> Self
where
N: Into<String>,
U: Into<String>,
{
Self {
commit,
author,
stamp,
id,
name: name.into(),
url: url.into(),
}
}
}
impl Display for Topic {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(
f,
"topic {} at {}, staged by {} at {}",
self.name, self.commit, self.author, self.stamp
)
}
}
impl PartialEq for Topic {
fn eq(&self, rhs: &Self) -> bool {
// The author and stamp time are explicitly not considered since they are not important to
// the actual topic comparison once on the stage.
self.commit == rhs.commit && self.id == rhs.id
}
}
/// A topic branch which should be integrated into the stage.
#[derive(Debug, Clone, PartialEq)]
pub struct CandidateTopic {
/// The old revision for the topic (if available).
pub old_id: Option<Topic>,
/// The new revision for the topic.
pub new_id: Topic,
}
impl CandidateTopic {
fn is_self_consistent(&self) -> bool {
self.old_id
.as_ref()
.map_or(true, |old| old.id == self.new_id.id)
}
}
impl Display for CandidateTopic {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
if let Some(ref old_topic) = self.old_id {
write!(f, "candidate {}, replacing {}", self.new_id, old_topic)
} else {
write!(f, "candidate {}, new", self.new_id)
}
}
}
/// A topic branch which has been staged.
#[derive(Debug, Clone, PartialEq)]
pub struct StagedTopic {
/// The commit where the topic branch has been merged into the staging branch.
pub merge: CommitId,
/// The topic branch.
pub topic: Topic,
}
impl StagedTopic {
/// The HEAD commit of the topic branch.
pub fn commit(&self) -> &CommitId {
&self.topic.commit
}
}
impl Display for StagedTopic {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "staged {}, via {}", self.topic, self.merge)
}
}
/// Reasons for which a branch can be unstaged.
pub enum UnstageReason {
/// Conflicts occurred while merging the topic.
MergeConflict(Vec<Conflict>),
}
impl Debug for UnstageReason {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
UnstageReason::MergeConflict(ref conflicts) => {
write!(f, "MergeConflict ( {} conflicts )", conflicts.len())
},
}
}
}
/// Reasons an old topic was removed from the stage.
#[derive(Debug)]
pub enum OldTopicRemoval {
/// The topic branch has been obsoleted by an update.
Obsoleted {
/// The old topic, as staged.
old_merge: StagedTopic,
/// The staged topic branch which has replaced the old topic branch.
replacement: Option<StagedTopic>,
},
/// The topic branch has been removed, without replacement, from the stage.
Removed(StagedTopic),
}
impl OldTopicRemoval {
/// The topic branch which was removed.
pub fn topic(&self) -> &Topic {
match *self {
OldTopicRemoval::Obsoleted {
old_merge: ref ob, ..
} => &ob.topic,
OldTopicRemoval::Removed(ref rb) => &rb.topic,
}
}
}
/// Results from integrating a topic.
#[derive(Debug)]
pub enum IntegrationResult {
/// The topic is successfully staged into the integration branch.
Staged(StagedTopic),
/// The topic is kicked out of the integration branch.
Unstaged(Topic, UnstageReason),
/// The topic is not mergeable.
Unmerged(Topic, MergeStatus),
}
impl IntegrationResult {
/// The topic branch.
pub fn topic(&self) -> &Topic {
match *self {
IntegrationResult::Staged(ref sb) => &sb.topic,
IntegrationResult::Unstaged(ref u, _) => u,
IntegrationResult::Unmerged(ref t, _) => t,
}
}
/// Whether the topic branch is currently staged or not.
pub fn on_stage(&self) -> bool {
match *self {
IntegrationResult::Staged(_) => true,
IntegrationResult::Unstaged(_, _) | IntegrationResult::Unmerged(_, _) => false,
}
}
}
/// The result of rewinding the stage back to a point where new commits may be applied.
///
/// The order is such that the first pair represents the old state of the staged topics while the
/// last pair represents the topics which need to be re-integrated into the staging branch.
type RewoundStage = (Option<StagedTopic>, Vec<StagedTopic>, Option<Topic>);
/// The results of a stage operation.
#[derive(Debug)]
pub struct StageResult {
/// The branch which the operation removed from the stage.
pub old_topic: Option<OldTopicRemoval>,
/// Results from reintegrating the other staged topics.
///
/// Other topics may need to be merged into the integration result again and may fail to merge
/// once another topic is removed from the branch.
pub results: Vec<IntegrationResult>,
}
/// A manager for an integration branch.
///
/// This stores the state of a staging branch and the representative topics.
#[derive(Debug)]
pub struct Stager {
/// The git context for the stager to work in.
ctx: GitContext,
/// The ordered set of topics currently merged into the topic stage.
topics: Vec<StagedTopic>,
}
/// The summary prefix to use when staging topics.
const STAGE_TOPIC_PREFIX: &str = "Stage topic '";
/// The summary suffix to use when staging topics.
const STAGE_TOPIC_SUFFIX: &str = "'";
/// The trailer to use for the ID of the topic.
const TOPIC_ID_TRAILER: &str = "Topic-id: ";
/// The trailer to use for the URL of the topic.
const TOPIC_URL_TRAILER: &str = "Topic-url: ";
impl Stager {
/// Create a new stage from the given commit.
pub fn new(ctx: &GitContext, base: CommitId) -> Self {
Self {
ctx: ctx.clone(),
topics: vec![Self::make_base_staged_topic(base)],
}
}
/// Create a new stage, discovering topics which have been merged into an integration branch.
///
/// This constructor takes a base branch and the name of the stage branch. It queries the given
/// Git context for the history of the stage branch from the base and constructs its state from
/// its first parent history.
///
/// If the stage does not exist, it is created with the base commit as its start.
///
/// Fails if the stage branch history does not appear to be a proper stage branch. A proper
/// stage branch's first parent history from the base consists only of merge commits with
/// exactly two parents with required information in its commit message.
pub fn from_branch(ctx: &GitContext, base: CommitId, stage: CommitId) -> StagerResult<Self> {
let cat_file = ctx
.git()
.arg("cat-file")
.arg("-t")
.arg(stage.as_str())
.output()
.map_err(|err| GitError::subcommand("cat-file", err))?;
if cat_file.status.success() {
// Ensure that the stage ref is a commit.
let stage_type = String::from_utf8_lossy(&cat_file.stdout);
if stage_type.trim() != "commit" {
return Err(StagerError::invalid_branch(
stage,
InvalidCommitReason::NotACommit,
));
}
} else {
// Create the stage ref.
let update_ref = ctx
.git()
.arg("update-ref")
.arg(stage.as_str())
.arg(base.as_str())
.output()
.map_err(|err| GitError::subcommand("update-ref", err))?;
if !update_ref.status.success() {
return Err(StagerError::create_stage_ref(
stage,
base,
&update_ref.stderr,
));
}
}
// Check if the stage ref needs updated for the new base.
let is_ancestor = ctx
.git()
.arg("merge-base")
.arg("--is-ancestor")
.arg(base.as_str())
.arg(stage.as_str())
.status()
.map_err(|err| GitError::subcommand("merge-base --is-ancestor", err))?;
let needs_base_update = !is_ancestor.success();
debug!(target: "git-topic-stage", "creating a stage branch from {} -> {}", base, stage);
// Find the merge base to create the base topic.
let merge_base = ctx
.git()
.arg("merge-base")
.arg(base.as_str())
.arg(stage.as_str())
.output()
.map_err(|err| GitError::subcommand("merge-base", err))?;
if !merge_base.status.success() {
return Err(StagerError::invalid_branch(
stage,
InvalidCommitReason::NotRelated,
));
}
let merge_base = String::from_utf8_lossy(&merge_base.stdout);
let mut topics = vec![Self::make_base_staged_topic(CommitId::new(
merge_base.trim(),
))];
// Get the first parent history of the stage ref that are not in the base. Also include the
// parents of the commits so the topic set can be reconstructed.
let rev_list = ctx
.git()
.arg("rev-list")
.arg("--first-parent")
.arg("--reverse")
.arg("--parents")
.arg(stage.as_str())
.arg(&format!("^{}", base))
.output()
.map_err(|err| GitError::subcommand("rev-list --first-parent", err))?;
if !rev_list.status.success() {
return Err(StagerError::list_stage_history(&rev_list.stderr));
}
let merges = String::from_utf8_lossy(&rev_list.stdout);
// Parse out our merge history.
let new_topics = merges
.lines()
.map(|merge| {
// Get the parents of the merge commit.
let revs = merge.split_whitespace().collect::<Vec<_>>();
let (rev, parents) = revs[..].split_first().expect("invalid rev-list format");
let rev_commit = CommitId::new(*rev);
// The stage should be constructed only of merge commits.
//
// This may happen if the target branch has been rewound while the stage has the
// original history.
if parents.len() == 1 {
return Err(StagerError::invalid_branch(
rev_commit,
InvalidCommitReason::NonMergeCommit,
));
}
// Though octopus merges are also not allowed.
if parents.len() > 2 {
return Err(StagerError::invalid_branch(
rev_commit,
InvalidCommitReason::OctopusMerge,
));
}
// Extract all of the information from a commit in order to recreate the
// `StageTopic` structure.
let commit_info = ctx
.git()
.arg("log")
.arg("--max-count=1")
.arg("--pretty=%an%n%ae%n%aI%n%B")
.arg(rev)
.output()
.map_err(|err| GitError::subcommand("log", err))?;
if !commit_info.status.success() {
return Err(StagerError::extract_merge_info(&commit_info.stderr));
}
let info = String::from_utf8_lossy(&commit_info.stdout);
let info = info.lines().collect::<Vec<_>>();
// Sanity check that we got the information we want.
if info.len() <= 6 {
return Err(StagerError::invalid_stage_merge(rev, &commit_info.stdout));
}
// Extract out the name of the topic from the merge commit message summary.
let subject = info[3];
if !subject.starts_with(STAGE_TOPIC_PREFIX)
|| !subject.ends_with(STAGE_TOPIC_SUFFIX)
{
let reason = InvalidCommitReason::InvalidSubject(subject.into());
return Err(StagerError::invalid_branch(rev_commit, reason));
}
let name =
&subject[STAGE_TOPIC_PREFIX.len()..subject.len() - STAGE_TOPIC_SUFFIX.len()];
let mut id = None;
let mut url = None;
// Parse trailers from the commit message.
for line in info[5..info.len() - 1].iter().rev() {
if line.is_empty() {
break;
} else if let Some(topic_id) = line.strip_prefix(TOPIC_ID_TRAILER) {
id = Some(topic_id.parse().map_err(|err| {
let reason = InvalidCommitReason::UnparseableId(format!("{}", err));
StagerError::invalid_branch(rev_commit.clone(), reason)
})?);
} else if let Some(topic_url) = line.strip_prefix(TOPIC_URL_TRAILER) {
url = Some(topic_url.to_string());
} else {
// Not a real issue, but this is unexpected.
warn!(
target: "git-topic-stage",
"unrecognized trailer in {}: {}",
parents[1],
line,
);
}
}
// Check that we have the information we need to create a `StagedTopic`.
let url = if let Some(url) = url {
url
} else {
return Err(StagerError::invalid_branch(
rev_commit,
InvalidCommitReason::MissingUrl,
));
};
let id = match id {
Some(0) => {
return Err(StagerError::invalid_branch(
rev_commit,
InvalidCommitReason::ZeroId,
));
},
Some(id) => id,
None => {
return Err(StagerError::invalid_branch(
rev_commit,
InvalidCommitReason::MissingId,
));
},
};
info!(
target: "git-topic-stage",
"found staged topic '{}' from {}",
name, url,
);
Ok(StagedTopic {
merge: rev_commit,
topic: Topic::new(
CommitId::new(parents[1]),
Identity::new(info[0], info[1]),
info[2].parse().map_err(StagerError::date_parse)?,
id,
name,
url,
),
})
})
.collect::<StagerResult<Vec<_>>>()?;
topics.extend(new_topics.into_iter());
// Verify that there are no duplicate topic IDs.
let mut ids = HashSet::new();
for topic in &topics {
if !ids.insert(topic.topic.id) {
return Err(StagerError::duplicate_topic_id(topic.topic.id));
}
}
let mut stager = Self {
ctx: ctx.clone(),
topics,
};
// If the target branch for the stage branch has been updated, perform a stage of a topic
// which updates to the current state of the branch.
if needs_base_update {
let base_update = CandidateTopic {
old_id: Some(Self::make_base_topic(CommitId::new(merge_base.trim()))),
new_id: Self::make_base_topic(base),
};
stager.stage(base_update)?;
}
Ok(stager)
}
/// Returns the git context the stager uses for operations.
pub fn git_context(&self) -> &GitContext {
&self.ctx
}
/// Returns the base branch for the integration branch.
pub fn base(&self) -> &CommitId {
self.topics[0].commit()
}
/// The topics which have been merged into the stage.
pub fn topics(&self) -> &[StagedTopic] {
&self.topics[1..]
}
/// The a topic on the stage by its ID.
pub fn find_topic_by_id(&self, id: u64) -> Option<&StagedTopic> {
self.topics()
.iter()
.find(|staged_topic| id == staged_topic.topic.id)
}
/// Find where a topic has been merged into the integration branch.
pub fn find_topic(&self, topic: &Topic) -> Option<&StagedTopic> {
self.topics()
.iter()
.find(|staged_topic| topic == &staged_topic.topic)
}
/// Returns the newest commit in the integration branch.
pub fn head(&self) -> &CommitId {
&self
.topics
.iter()
.last()
.expect("expected there to be a HEAD topic on the stage")
.merge
}
/// Make a new staged topic structure from a commit, assuming it is the base of the stage.
fn make_base_staged_topic(base: CommitId) -> StagedTopic {
StagedTopic {
merge: base.clone(),
topic: Self::make_base_topic(base),
}
}
/// Make a topic structure from a commit, assuming it is the base of the stage.
fn make_base_topic(base: CommitId) -> Topic {
Topic {
commit: base,
author: Identity::new("stager", "stager@example.com"),
stamp: Utc::now(),
id: 0,
name: "base".into(),
url: "url".into(),
}
}
/// Rewind a stage to the topic right before a topic was merged.
fn rewind_stage(&mut self, topic: CandidateTopic) -> RewoundStage {
// Find the topic branch's old commit in the current stage.
let root = topic
.old_id
.and_then(|old| {
self.topics
.iter()
.position(|staged_topic| old == staged_topic.topic)
})
.unwrap_or(self.topics.len());
// Grab the branches which must be restaged.
let mut old_stage = self.topics.drain(root..).collect::<Vec<_>>();
if self.topics.is_empty() {
debug!(target: "git-topic-stage", "rewinding the stage to its base");
} else {
debug!(target: "git-topic-stage", "rewinding the stage to {}", self.head());
}
let (old_topic, new_topic) = if self.topics.is_empty() {
// The base is being replaced.
self.topics
.push(Self::make_base_staged_topic(topic.new_id.commit));
// The old topic branch is the first one in the list of branches that need to be
// restaged, so remove it from the vector.
(Some(old_stage.remove(0)), None)
} else if old_stage.is_empty() {
// This topic is brand new.
(None, Some(topic.new_id))
} else {
// The old topic branch is the first one in the list of branches that need to be
// restaged, so remove it from the vector.
(Some(old_stage.remove(0)), Some(topic.new_id))
};
(old_topic, old_stage, new_topic)
}
/// Replay a set of topics onto the stage.
fn replay_stage(
&mut self,
old_stage: Vec<StagedTopic>,
) -> StagerResult<Vec<IntegrationResult>> {
debug!(target: "git-topic-stage", "replaying {} branches into the stage", old_stage.len());
// Restage old branches.
old_stage
.into_iter()
.map(|old_staged_topic| {
let (staged, res) = self.merge_to_stage(old_staged_topic.topic)?;
if let Some(t) = staged {
self.topics.push(t);
}
Ok(res)
})
.collect()
}
/// Remove a topic from the stage.
pub fn unstage(&mut self, topic: StagedTopic) -> StagerResult<StageResult> {
info!(target: "git-topic-stage", "unstaging a topic: {}", topic);
if topic.commit() == self.base() {
debug!(target: "git-topic-stage", "ignoring a request to unstage the base");
return Err(StagerError::CannotUnstageBase);
}
let (old_topic, old_stage, new_topic) = self.rewind_stage(CandidateTopic {
old_id: Some(topic.topic.clone()),
new_id: topic.topic,
});
let results = self.replay_stage(old_stage)?;
if new_topic.is_none() {
// Requested the unstaging of the base branch.
warn!(target: "git-topic-stage", "unstage called on the base branch");
}
if let Some(ref old_topic) = old_topic {
debug!(target: "git-topic-stage", "unstaged {}", old_topic);
}
// Give some information about the old topic branch (if it existed).
let old_branch_result = old_topic.map(OldTopicRemoval::Removed);
Ok(StageResult {
old_topic: old_branch_result,
results,
})
}
/// Add a topic branch to the stage.
///
/// If the branch already existed on the staging branch, it is first removed from the stage and
/// then any topics which were merged after it are merged again, in order. The updated topic is
/// then merged as the last operation.
pub fn stage(&mut self, topic: CandidateTopic) -> StagerResult<StageResult> {
info!(target: "git-topic-stage", "staging a topic: {}", topic);
let self_consistent = topic.is_self_consistent();
if !self_consistent || topic.old_id.is_none() {
if !self_consistent {
warn!(
target: "git-topic-stage",
"inconsistent candidate topic submission: {}",
topic,
);
}
if self
.topics
.iter()
.any(|staged| staged.topic.id == topic.new_id.id)
{
return Err(StagerError::duplicate_topic_id(topic.new_id.id));
}
}
// Rewind the stage.
let (old_topic, old_stage, new_topic) = self.rewind_stage(topic);
let mut results = self.replay_stage(old_stage)?;
let old_branch_result = if let Some(topic) = new_topic {
// Apply the new topic branch.
let (staged, res) = self.merge_to_stage(topic)?;
if let Some(sb) = staged.clone() {
self.topics.push(sb);
}
results.push(res);
// Give some information about the old topic branch (if it existed).
old_topic.map(|topic| {
OldTopicRemoval::Obsoleted {
old_merge: topic,
replacement: staged,
}
})
} else {
// The base of the branch was replaced; return the old stage base.
old_topic.map(|topic| {
OldTopicRemoval::Obsoleted {
old_merge: topic,
replacement: Some(self.topics[0].clone()),
}
})
};
Ok(StageResult {
old_topic: old_branch_result,
results,
})
}
/// Remove all staged topics from the staging branch.
///
/// Previously staged topics are returned.
pub fn clear(&mut self) -> Vec<StagedTopic> {
let new_id = Self::make_base_staged_topic(self.base().clone()).topic;
let old_id = Some(new_id.clone());
info!(target: "git-topic-stage", "clearing the stage");
self.rewind_stage(CandidateTopic {
old_id,
new_id,
})
.1
}
/// Merge a topic into the stage.
fn merge_to_stage(
&self,
topic: Topic,
) -> StagerResult<(Option<StagedTopic>, IntegrationResult)> {
let base_commit = self.base();
let head_commit = self.head();
let topic_commit = topic.commit.clone();
debug!(target: "git-topic-stage", "merging {} into the stage", topic);
// Check that the topic is mergeable against the *base* commit. New root commits may have
// appeared in topic branches that have since been merged. Checking against the base commit
// ensures that it at least has a chance if it becomes the first branch on the stage again.
let merge_status = self.ctx.mergeable(base_commit, &topic_commit)?;
let bases = if let MergeStatus::Mergeable(bases) = merge_status {
bases
} else {
// Reject branches which are not mergeable.
debug!(target: "git-topic-stage", "rejecting: unmergeable: {}", merge_status);
return Ok((None, IntegrationResult::Unmerged(topic, merge_status)));
};
// Prepare a workarea in which to perform the merge.
let workarea = self.ctx.prepare(head_commit)?;
// Prepare the merged tree.
let merge_result = workarea.setup_merge(&bases, head_commit, &topic_commit)?;
let mut merge_command = match merge_result {
MergeResult::Conflict(conflicts) => {
debug!(target: "git-topic-stage", "rejecting: conflicts: {}", conflicts.len());
return Ok((
None,
IntegrationResult::Unstaged(topic, UnstageReason::MergeConflict(conflicts)),
));
},
MergeResult::Ready(command) => command,
};
// Add metadata about the stage request to the commit.
merge_command.author(&topic.author).author_date(topic.stamp);
// Commit the merged tree.
let merge_commit = merge_command.commit(self.create_message(self.base(), &topic))?;
let staged_topic = StagedTopic {
merge: merge_commit,
topic,
};
debug!(target: "git-topic-stage", "successfully staged as {}", staged_topic);
Ok((
Some(staged_topic.clone()),
IntegrationResult::Staged(staged_topic),
))
}
/// Create the merge commit message for a topic.
fn create_message(&self, _: &CommitId, topic: &Topic) -> String {
format!(
"{}{}{}\n\n{}{}\n{}{}\n",
STAGE_TOPIC_PREFIX,
topic.name,
STAGE_TOPIC_SUFFIX,
TOPIC_ID_TRAILER,
topic.id,
TOPIC_URL_TRAILER,
topic.url,
)
}
}