Merge pull request #559 from libgit2/piet/write-merge-conflicted-files

Write merge conflicted files when pulling

Author: joshaber

ObjectiveGit/GTRepository+Merging.h

@@ -0,0 +1,67 @@
+//
+//  GTRepository+Merging.h
+//  ObjectiveGitFramework
+//
+//  Created by Piet Brauer on 02/03/16.
+//  Copyright © 2016 GitHub, Inc. All rights reserved.
+//
+
+#import "GTRepository.h"
+#import "git2/merge.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/// UserInfo key for conflicted files when pulling fails with a merge conflict
+extern NSString * const GTPullMergeConflictedFiles;
+
+/// An enum describing the result of the merge analysis.
+/// See `git_merge_analysis_t`.
+typedef NS_OPTIONS(NSInteger, GTMergeAnalysis) {
+	GTMergeAnalysisNone = GIT_MERGE_ANALYSIS_NONE,
+	GTMergeAnalysisNormal = GIT_MERGE_ANALYSIS_NORMAL,
+	GTMergeAnalysisUpToDate = GIT_MERGE_ANALYSIS_UP_TO_DATE,
+	GTMergeAnalysisUnborn = GIT_MERGE_ANALYSIS_UNBORN,
+	GTMergeAnalysisFastForward = GIT_MERGE_ANALYSIS_FASTFORWARD,
+};
+
+@interface GTRepository (Merging)
+
+/// Enumerate all available merge head entries.
+///
+/// error - The error if one ocurred. Can be NULL.
+/// block - A block to execute for each MERGE_HEAD entry. `mergeHeadEntry` will
+///         be the current merge head entry. Setting `stop` to YES will cause
+///         enumeration to stop after the block returns. Must not be nil.
+///
+/// Returns YES if the operation succedded, NO otherwise.
+- (BOOL)enumerateMergeHeadEntriesWithError:(NSError **)error usingBlock:(void (^)(GTOID *mergeHeadEntry, BOOL *stop))block;
+
+/// Convenience method for -enumerateMergeHeadEntriesWithError:usingBlock: that retuns an NSArray with all the fetch head entries.
+///
+/// error - The error if one ocurred. Can be NULL.
+///
+/// Retruns a (possibly empty) array with GTOID objects. Will not be nil.
+- (NSArray <GTOID *>*)mergeHeadEntriesWithError:(NSError **)error;
+
+/// Merge Branch into current branch
+///
+/// fromBranch - The branch to merge from.
+/// error      - The error if one occurred. Can be NULL.
+///
+/// Returns YES if the merge was successful, NO otherwise (and `error`, if provided,
+/// will point to an error describing what happened).
+- (BOOL)mergeBranchIntoCurrentBranch:(GTBranch *)fromBranch withError:(NSError **)error;
+
+/// Analyze which merge to perform.
+///
+/// analysis   - The resulting analysis.
+/// fromBranch - The branch to merge from.
+/// error      - The error if one occurred. Can be NULL.
+///
+/// Returns YES if the analysis was successful, NO otherwise (and `error`, if provided,
+/// will point to an error describing what happened).
+- (BOOL)analyzeMerge:(GTMergeAnalysis *)analysis fromBranch:(GTBranch *)fromBranch error:(NSError **)error;
+
+@end
+
+NS_ASSUME_NONNULL_END

ObjectiveGit/GTRepository+Merging.m

@@ -0,0 +1,212 @@
+//
+//  GTRepository+Merging.m
+//  ObjectiveGitFramework
+//
+//  Created by Piet Brauer on 02/03/16.
+//  Copyright © 2016 GitHub, Inc. All rights reserved.
+//
+
+#import "GTRepository+Merging.h"
+#import "GTOID.h"
+#import "NSError+Git.h"
+#import "git2/errors.h"
+#import "GTCommit.h"
+#import "GTReference.h"
+#import "GTRepository+Committing.h"
+#import "GTRepository+Pull.h"
+#import "GTTree.h"
+#import "GTIndex.h"
+#import "GTIndexEntry.h"
+
+typedef void (^GTRemoteFetchTransferProgressBlock)(const git_transfer_progress *stats, BOOL *stop);
+
+@implementation GTRepository (Merging)
+
+typedef void (^GTRepositoryEnumerateMergeHeadEntryBlock)(GTOID *entry, BOOL *stop);
+
+typedef struct {
+	__unsafe_unretained GTRepositoryEnumerateMergeHeadEntryBlock enumerationBlock;
+} GTEnumerateMergeHeadEntriesPayload;
+
+int GTMergeHeadEntriesCallback(const git_oid *oid, void *payload) {
+	GTEnumerateMergeHeadEntriesPayload *entriesPayload = payload;
+
+	GTRepositoryEnumerateMergeHeadEntryBlock enumerationBlock = entriesPayload->enumerationBlock;
+
+	GTOID *gtoid = [GTOID oidWithGitOid:oid];
+
+	BOOL stop = NO;
+
+	enumerationBlock(gtoid, &stop);
+
+	return (stop == YES ? GIT_EUSER : 0);
+}
+
+- (BOOL)enumerateMergeHeadEntriesWithError:(NSError **)error usingBlock:(void (^)(GTOID *mergeHeadEntry, BOOL *stop))block {
+	NSParameterAssert(block != nil);
+
+	GTEnumerateMergeHeadEntriesPayload payload = {
+		.enumerationBlock = block,
+	};
+
+	int gitError = git_repository_mergehead_foreach(self.git_repository, GTMergeHeadEntriesCallback, &payload);
+
+	if (gitError != GIT_OK) {
+		if (error != NULL) *error = [NSError git_errorFor:gitError description:@"Failed to get mergehead entries"];
+		return NO;
+	}
+
+	return YES;
+}
+
+- (NSArray *)mergeHeadEntriesWithError:(NSError **)error {
+	NSMutableArray *entries = [NSMutableArray array];
+
+	[self enumerateMergeHeadEntriesWithError:error usingBlock:^(GTOID *mergeHeadEntry, BOOL *stop) {
+		[entries addObject:mergeHeadEntry];
+
+		*stop = NO;
+	}];
+
+	return entries;
+}
+
+- (BOOL)mergeBranchIntoCurrentBranch:(GTBranch *)branch withError:(NSError **)error {
+	// Check if merge is necessary
+	GTBranch *localBranch = [self currentBranchWithError:error];
+	if (!localBranch) {
+		return NO;
+	}
+
+	GTCommit *localCommit = [localBranch targetCommitWithError:error];
+	if (!localCommit) {
+		return NO;
+	}
+
+	GTCommit *remoteCommit = [branch targetCommitWithError:error];
+	if (!remoteCommit) {
+		return NO;
+	}
+
+	if ([localCommit.SHA isEqualToString:remoteCommit.SHA]) {
+		// Local and remote tracking branch are already in sync
+		return YES;
+	}
+
+	GTMergeAnalysis analysis = GTMergeAnalysisNone;
+	BOOL success = [self analyzeMerge:&analysis fromBranch:branch error:error];
+	if (!success) {
+		return NO;
+	}
+
+	if (analysis & GTMergeAnalysisUpToDate) {
+		// Nothing to do
+		return YES;
+	} else if (analysis & GTMergeAnalysisFastForward ||
+			   analysis & GTMergeAnalysisUnborn) {
+		// Fast-forward branch
+		NSString *message = [NSString stringWithFormat:@"merge %@: Fast-forward", branch.name];
+		GTReference *reference = [localBranch.reference referenceByUpdatingTarget:remoteCommit.SHA message:message error:error];
+		BOOL checkoutSuccess = [self checkoutReference:reference strategy:GTCheckoutStrategyForce error:error progressBlock:nil];
+
+		return checkoutSuccess;
+	} else if (analysis & GTMergeAnalysisNormal) {
+		// Do normal merge
+		GTTree *localTree = localCommit.tree;
+		GTTree *remoteTree = remoteCommit.tree;
+
+		// TODO: Find common ancestor
+		GTTree *ancestorTree = nil;
+
+		// Merge
+		GTIndex *index = [localTree merge:remoteTree ancestor:ancestorTree error:error];
+		if (!index) {
+			return NO;
+		}
+
+		// Check for conflict
+		if (index.hasConflicts) {
+			NSMutableArray <NSString *>*files = [NSMutableArray array];
+			[index enumerateConflictedFilesWithError:error usingBlock:^(GTIndexEntry * _Nonnull ancestor, GTIndexEntry * _Nonnull ours, GTIndexEntry * _Nonnull theirs, BOOL * _Nonnull stop) {
+				[files addObject:ours.path];
+			}];
+
+			if (error != NULL) {
+				NSDictionary *userInfo = @{GTPullMergeConflictedFiles: files};
+				*error = [NSError git_errorFor:GIT_ECONFLICT description:@"Merge conflict" userInfo:userInfo failureReason:nil];
+			}
+
+			// Write conflicts
+			git_merge_options merge_opts = GIT_MERGE_OPTIONS_INIT;
+			git_checkout_options checkout_opts = GIT_CHECKOUT_OPTIONS_INIT;
+			checkout_opts.checkout_strategy = GIT_CHECKOUT_ALLOW_CONFLICTS;
+
+			git_annotated_commit *annotatedCommit;
+			[self annotatedCommit:&annotatedCommit fromCommit:remoteCommit error:error];
+
+			git_merge(self.git_repository, (const git_annotated_commit **)&annotatedCommit, 1, &merge_opts, &checkout_opts);
+
+			return NO;
+		}
+
+		GTTree *newTree = [index writeTreeToRepository:self error:error];
+		if (!newTree) {
+			return NO;
+		}
+
+		// Create merge commit
+		NSString *message = [NSString stringWithFormat:@"Merge branch '%@'", localBranch.shortName];
+		NSArray *parents = @[ localCommit, remoteCommit ];
+
+		// FIXME: This is stepping on the local tree
+		GTCommit *mergeCommit = [self createCommitWithTree:newTree  message:message parents:parents updatingReferenceNamed:localBranch.name error:error];
+		if (!mergeCommit) {
+			return NO;
+		}
+
+		BOOL success = [self checkoutReference:localBranch.reference strategy:GTCheckoutStrategyForce error:error progressBlock:nil];
+		return success;
+	}
+
+	return NO;
+}
+
+- (BOOL)annotatedCommit:(git_annotated_commit **)annotatedCommit fromCommit:(GTCommit *)fromCommit error:(NSError **)error {
+	int gitError = git_annotated_commit_lookup(annotatedCommit, self.git_repository, fromCommit.OID.git_oid);
+	if (gitError != GIT_OK) {
+		if (error != NULL) *error = [NSError git_errorFor:gitError description:@"Failed to lookup annotated commit for %@", fromCommit];
+		return NO;
+	}
+
+	return YES;
+}
+
+- (BOOL)analyzeMerge:(GTMergeAnalysis *)analysis fromBranch:(GTBranch *)fromBranch error:(NSError **)error {
+	NSParameterAssert(analysis != NULL);
+	NSParameterAssert(fromBranch != nil);
+
+	GTCommit *fromCommit = [fromBranch targetCommitWithError:error];
+	if (!fromCommit) {
+		return NO;
+	}
+
+	git_annotated_commit *annotatedCommit;
+	[self annotatedCommit:&annotatedCommit fromCommit:fromCommit error:error];
+
+	// Allow fast-forward or normal merge
+	git_merge_preference_t preference = GIT_MERGE_PREFERENCE_NONE;
+
+	// Merge analysis
+	int gitError = git_merge_analysis((git_merge_analysis_t *)analysis, &preference, self.git_repository, (const git_annotated_commit **) &annotatedCommit, 1);
+	if (gitError != GIT_OK) {
+		if (error != NULL) *error = [NSError git_errorFor:gitError description:@"Failed to analyze merge"];
+		return NO;
+	}
+
+	// Cleanup
+	git_annotated_commit_free(annotatedCommit);
+
+	return YES;
+}
+
+@end

ObjectiveGit/GTRepository+Pull.h

@@ -7,23 +7,9 @@
 //
 
 #import "GTRepository.h"
-#import "git2/merge.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
-/// UserInfo key for conflicted files when pulling fails with a merge conflict
-extern NSString * const GTPullMergeConflictedFiles;
-
-/// An enum describing the result of the merge analysis.
-/// See `git_merge_analysis_t`.
-typedef NS_OPTIONS(NSInteger, GTMergeAnalysis) {
-	GTMergeAnalysisNone = GIT_MERGE_ANALYSIS_NONE,
-	GTMergeAnalysisNormal = GIT_MERGE_ANALYSIS_NORMAL,
-	GTMergeAnalysisUpToDate = GIT_MERGE_ANALYSIS_UP_TO_DATE,
-	GTMergeAnalysisUnborn = GIT_MERGE_ANALYSIS_UNBORN,
-	GTMergeAnalysisFastForward = GIT_MERGE_ANALYSIS_FASTFORWARD,
-};
-
 typedef void (^GTRemoteFetchTransferProgressBlock)(const git_transfer_progress *progress, BOOL *stop);
 
 @interface GTRepository (Pull)
@@ -44,16 +30,6 @@ typedef void (^GTRemoteFetchTransferProgressBlock)(const git_transfer_progress *
 /// will point to an error describing what happened).
 - (BOOL)pullBranch:(GTBranch *)branch fromRemote:(GTRemote *)remote withOptions:(nullable NSDictionary *)options error:(NSError **)error progress:(nullable GTRemoteFetchTransferProgressBlock)progressBlock;
 
-/// Analyze which merge to perform.
-///
-/// analysis   - The resulting analysis.
-/// fromBranch - The branch to merge from.
-/// error      - The error if one occurred. Can be NULL.
-///
-/// Returns YES if the analysis was successful, NO otherwise (and `error`, if provided,
-/// will point to an error describing what happened).
-- (BOOL)analyzeMerge:(GTMergeAnalysis *)analysis fromBranch:(GTBranch *)fromBranch error:(NSError **)error;
-
 @end
 
 NS_ASSUME_NONNULL_END