Fixes issue with diff with previous and renames

CHANGELOG.md

@@ -18,6 +18,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/) and this p
 - Fixes [#436](https://github.com/eamodio/vscode-gitlens/issues/436) - Copy to clipboard not working
 - Fixes [#442](https://github.com/eamodio/vscode-gitlens/issues/442) - GitLens File History fails if name (or path) starts with -
 - Fixes [#440](https://github.com/eamodio/vscode-gitlens/issues/436) - Searching for commits with an empty query yields to no results anymore
+- Fixes issue where the *Compare File with Previous Revision* command wouldn't work properly when the file had been renamed in some cases
 - Fixes issue where changed files count was wrong when the branch was behind the upstream
 - Fixes issue where the *GitLens File History* explorer wasn't being updated automatically for working changes
 - Fixes issue where the *Compare File with * Revision* commands in the editor toolbar would show and hide too often because of insignificant focus changes

src/commands/diffWithPrevious.ts

@@ -58,16 +58,39 @@ export class DiffWithPreviousCommand extends ActiveEditorCommand {
                     sha = sha + '^';
                 }
 
-                const log = await Container.git.getLogForFile(gitUri.repoPath, gitUri.fsPath, {
+                args.commit = undefined;
+
+                let log = await Container.git.getLogForFile(gitUri.repoPath, gitUri.fsPath, {
                     maxCount: 2,
                     ref: sha,
                     renames: true
                 });
-                if (log === undefined) {
-                    return Messages.showFileNotUnderSourceControlWarningMessage('Unable to open compare');
+
+                if (log !== undefined) {
+                    args.commit = (sha && log.commits.get(sha)) || Iterables.first(log.commits.values());
                 }
+                else {
+                    // Only kick out if we aren't looking for the previous sha -- since renames won't return a log above
+                    if (sha === undefined || !sha.endsWith('^')) {
+                        return Messages.showFileNotUnderSourceControlWarningMessage('Unable to open compare');
+                    }
+
+                    // Check for renames
+                    log = await Container.git.getLogForFile(gitUri.repoPath, gitUri.fsPath, {
+                        maxCount: 4,
+                        ref: sha.substring(0, sha.length - 1),
+                        renames: true
+                    });
 
-                args.commit = (sha && log.commits.get(sha)) || Iterables.first(log.commits.values());
+                    if (log === undefined) {
+                        return Messages.showFileNotUnderSourceControlWarningMessage('Unable to open compare');
+                    }
+
+                    args.commit = Iterables.next(Iterables.skip(log.commits.values(), 2));
+                    if (args.commit === undefined) {
+                        args.commit = (sha && log.commits.get(sha)) || Iterables.first(log.commits.values());
+                    }
+                }
 
                 // If the sha is missing (i.e. working tree), check the file status
                 // If file is uncommitted, then treat it as a DiffWithWorking

src/system/iterable.ts

@@ -133,10 +133,7 @@ export namespace Iterables {
         return source.next().value;
     }
 
-    export function* skip<T>(
-        source: Iterable<T> | IterableIterator<T>,
-        count: number
-    ): Iterable<T> | IterableIterator<T> {
+    export function* skip<T>(source: Iterable<T> | IterableIterator<T>, count: number): IterableIterator<T> {
         let i = 0;
         for (const item of source) {
             if (i >= count) yield item;