Deals with resolved vs unresolved previous shas

src/commands/diffLineWithWorking.ts

@@ -58,7 +58,8 @@ export class DiffLineWithWorkingCommand extends ActiveEditorCommand {
 							args.commit.repoPath,
 						);
 					} else {
-						lhsSha = args.commit.file!.previousSha ?? GitRevision.deletedOrMissing;
+						// Don't need to worry about verifying the previous sha, as the DiffWith command will
+						lhsSha = args.commit.unresolvedPreviousSha;
 						lhsUri = args.commit.file!.originalUri ?? args.commit.file!.uri;
 					}
 				} else {

src/commands/diffWith.ts

@@ -30,7 +30,7 @@ export class DiffWithCommand extends Command {
 		let args: DiffWithCommandArgs | GitCommit;
 		if (GitCommit.is(argsOrCommit)) {
 			const commit = argsOrCommit;
-			if (commit.file == null) {
+			if (commit.file == null || commit.unresolvedPreviousSha == null) {
 				debugger;
 				throw new Error('Commit has no file');
 			}
@@ -52,7 +52,7 @@ export class DiffWithCommand extends Command {
 				args = {
 					repoPath: commit.repoPath,
 					lhs: {
-						sha: commit.file.previousSha ?? GitRevision.deletedOrMissing,
+						sha: commit.unresolvedPreviousSha,
 						uri: commit.file.originalUri ?? commit.file.uri,
 					},
 					rhs: {
@@ -91,10 +91,12 @@ export class DiffWithCommand extends Command {
 
 			[args.lhs.sha, args.rhs.sha] = await Promise.all([
 				await this.container.git.resolveReference(args.repoPath, args.lhs.sha, args.lhs.uri, {
-					timeout: 100,
+					// If the ref looks like a sha, don't wait too long, since it should work
+					timeout: GitRevision.isSha(args.lhs.sha) ? 100 : undefined,
 				}),
 				await this.container.git.resolveReference(args.repoPath, args.rhs.sha, args.rhs.uri, {
-					timeout: 100,
+					// If the ref looks like a sha, don't wait too long, since it should work
+					timeout: GitRevision.isSha(args.rhs.sha) ? 100 : undefined,
 				}),
 			]);
 

src/commands/externalDiff.ts

@@ -38,9 +38,8 @@ export class ExternalDiffCommand extends Command {
 		args = { ...args };
 
 		if (isCommandContextViewNodeHasFileCommit(context)) {
-			const ref1 = GitRevision.isUncommitted(context.node.commit.previousSha)
-				? ''
-				: context.node.commit.previousSha;
+			const previousSha = await context.node.commit.getPreviousSha();
+			const ref1 = GitRevision.isUncommitted(previousSha) ? '' : previousSha;
 			const ref2 = context.node.commit.isUncommitted ? '' : context.node.commit.sha;
 
 			args.files = [

src/commands/gitCommands.actions.ts

@@ -219,7 +219,8 @@ export namespace GitActions {
 				files = commitOrFiles.files ?? [];
 				refs = {
 					repoPath: commitOrFiles.repoPath,
-					ref1: commitOrFiles.previousSha != null ? commitOrFiles.previousSha : GitRevision.deletedOrMissing,
+					// Don't need to worry about verifying the previous sha, as the DiffWith command will
+					ref1: commitOrFiles.unresolvedPreviousSha,
 					ref2: commitOrFiles.sha,
 				};
 
@@ -361,8 +362,8 @@ export namespace GitActions {
 			const refs = GitCommit.is(commitOrRefs)
 				? {
 						repoPath: commitOrRefs.repoPath,
-						ref1:
-							commitOrRefs.previousSha != null ? commitOrRefs.previousSha : GitRevision.deletedOrMissing,
+						// Don't need to worry about verifying the previous sha, as the DiffWith command will
+						ref1: commitOrRefs.unresolvedPreviousSha,
 						ref2: commitOrRefs.sha,
 				  }
 				: commitOrRefs;
@@ -548,7 +549,7 @@ export namespace GitActions {
 				}
 
 				uri = Container.instance.git.getRevisionUri(
-					file.status === 'D' ? commit.previousSha : commit.sha,
+					file.status === 'D' ? (await commit.pan>getPreviousSha()) ?? GitRevision.deletedOrMissing : commit.sha,
 					file,
 					commit.repoPath,
 				);
@@ -633,7 +634,7 @@ export namespace GitActions {
 				files = commitOrFiles.files ?? [];
 				repoPath = commitOrFiles.repoPath;
 				ref1 = commitOrFiles.sha;
-				ref2 = commitOrFiles.previousSha;
+				ref2 = await commitOrFiles.getPreviousSha();
 			} else {
 				files = commitOrFiles;
 			}

src/commands/openCommitOnRemote.ts

@@ -82,7 +82,7 @@ export class OpenCommitOnRemoteCommand extends ActiveEditorCommand {
 
 				// If the line is uncommitted, use previous commit
 				args.sha = blame.commit.isUncommitted
-					? blame.commit.file!.previousSha ?? GitRevision.deletedOrMissing
+					? (await blame.commit.getPreviousSha()) ?? GitRevision.deletedOrMissing
 					: blame.commit.sha;
 			}
 

src/commands/openFileAtRevision.ts

@@ -60,18 +60,21 @@ export class OpenFileAtRevisionCommand extends ActiveEditorCommand {
 						const blame = await this.container.git.getBlameForLine(gitUri, editorLine);
 						if (blame != null) {
 							if (blame.commit.isUncommitted) {
-								const diffUris = await blame.commit.getPreviousComparisonUrisForLine(editorLine);
-								if (diffUris?.previous != null) {
-									args.revisionUri = this.container.git.getRevisionUri(diffUris.previous);
+								const comparisonUris = await blame.commit.getPreviousComparisonUrisForLine(editorLine);
+								if (comparisonUris?.previous != null) {
+									args.revisionUri = this.container.git.getRevisionUri(comparisonUris.previous);
 								} else {
 									void Messages.showCommitHasNoPreviousCommitWarningMessage(blame.commit);
 									return undefined;
 								}
-							} else if (blame?.commit.previousSha != null) {
-								args.revisionUri = this.container.git.getRevisionUri(blame.commit.getGitUri(true));
 							} else {
-								void Messages.showCommitHasNoPreviousCommitWarningMessage(blame.commit);
-								return undefined;
+								const previousSha = blame != null ? await blame?.commit.getPreviousSha() : undefined;
+								if (previousSha != null) {
+									args.revisionUri = this.container.git.getRevisionUri(blame.commit.getGitUri(true));
+								} else {
+									void Messages.showCommitHasNoPreviousCommitWarningMessage(blame.commit);
+									return undefined;
+								}
 							}
 						}
 					} catch (ex) {

src/commands/openRevisionFile.ts

@@ -2,6 +2,7 @@ import { TextDocumentShowOptions, TextEditor, Uri } from 'vscode';
 import { FileAnnotationType } from '../configuration';
 import type { Container } from '../container';
 import { GitUri } from '../git/gitUri';
+import { GitRevision } from '../git/models';
 import { Logger } from '../logger';
 import { Messages } from '../messages';
 import { ActiveEditorCommand, command, Commands, getCommandUri } from './common';
@@ -39,7 +40,11 @@ export class OpenRevisionFileCommand extends ActiveEditorCommand {
 
 					args.revisionUri =
 						commit?.file?.status === 'D'
-							? this.container.git.getRevisionUri(commit.previousSha, commit.file, commit.repoPath)
+							? this.container.git.getRevisionUri(
+									(await commit.getPreviousSha()) ?? GitRevision.deletedOrMissing,
+									commit.file,
+									commit.repoPath,
+							  )
 							: this.container.git.getRevisionUri(gitUri);
 				} else {
 					args.revisionUri = this.container.git.getRevisionUri(gitUri);

src/env/node/git/localGitProvider.ts

@@ -3502,12 +3502,18 @@ export class LocalGitProvider implements GitProvider, Disposable {
 
 	@log()
 	async resolveReference(repoPath: string, ref: string, pathOrUri?: string | Uri, options?: { timeout?: number }) {
-		if (!ref || ref === GitRevision.deletedOrMissing || GitRevision.isUncommitted(ref)) {
+		if (
+			!ref ||
+			ref === GitRevision.deletedOrMissing ||
+			(pathOrUri == null && GitRevision.isSha(ref)) ||
+			(pathOrUri != null && GitRevision.isUncommitted(ref))
+		) {
 			return ref;
 		}
 
 		if (pathOrUri == null) {
-			if (GitRevision.isSha(ref) || !GitRevision.isShaLike(ref) || ref.endsWith('^3')) return ref;
+			// If it doesn't look like a sha at all (e.g. branch name) or is a stash ref (^3) don't try to resolve it
+			if (!GitRevision.isShaLike(ref) || ref.endsWith('^3')) return ref;
 
 			return (await this.git.rev_parse__verify(repoPath, ref)) ?? ref;
 		}

src/git/formatters/commitFormatter.ts

@@ -319,10 +319,10 @@ export class CommitFormatter extends Formatter {
 			this._options.editor?.line,
 		)} "Open Changes with Previous Revision")`;
 
-		if (this._item.previousSha != null && this._item.file?.originalPath != null) {
+		if (this._item.file != null && this._item.unresolvedPreviousSha != null) {
 			const uri = Container.instance.git.getRevisionUri(
-				this._item.previousSha,
-				this._item.file.originalPath,
+				this._item.unresolvedPreviousSha,
+				this._item.file.originalPath ?? this._item.file?.path,
 				this._item.repoPath,
 			);
 			commands += `   [$(versions)](${OpenFileAtRevisionCommand.getMarkdownCommandArgs(

src/git/gitProviderService.ts

@@ -1845,7 +1845,12 @@ export class GitProviderService implements Disposable {
 		pathOrUri?: string | Uri,
 		options?: { timeout?: number },
 	) {
-		if (!ref || ref === GitRevision.deletedOrMissing || GitRevision.isUncommitted(ref)) {
+		if (
+			!ref ||
+			ref === GitRevision.deletedOrMissing ||
+			(pathOrUri == null && GitRevision.isSha(ref)) ||
+			(pathOrUri != null && GitRevision.isUncommitted(ref))
+		) {
 			return ref;
 		}
 

src/git/models/commit.ts

@@ -176,8 +176,11 @@ export class GitCommit implements GitRevisionReference {
 		return this._summary;
 	}
 
-	get previousSha(): string {
-		return this.file?.previousSha ?? this.parents[0] ?? `${this.sha}^`;
+	private _resolvedPreviousSha: string | undefined;
+	get unresolvedPreviousSha(): string {
+		if (this._resolvedPreviousSha != null) return this._resolvedPreviousSha;
+		if (this.file != null) return this.file.previousSha ?? `${this.sha}^`;
+		return this.parents[0] ?? `${this.sha}^`;
 	}
 
 	@gate()
@@ -189,6 +192,7 @@ export class GitCommit implements GitRevisionReference {
 			// Check for any untracked files -- since git doesn't return them via `git stash list` :(
 			// See https://stackoverflow.com/questions/12681529/
 			this.stashName ? this.container.git.getCommit(this.repoPath, `${this.stashName}^3`) : undefined,
+			this.getPreviousSha(),
 		]);
 		if (commitResult.status !== 'fulfilled' || commitResult.value == null) return;
 
@@ -403,7 +407,7 @@ export class GitCommit implements GitRevisionReference {
 
 		return new GitUri(this._file?.originalUri ?? uri, {
 			repoPath: this.repoPath,
-			sha: this.previousSha,
+			sha: this.unresolvedPreviousSha,
 		});
 	}
 
@@ -422,6 +426,40 @@ export class GitCommit implements GitRevisionReference {
 			: Promise.resolve(undefined);
 	}
 
+	private _previousShaPromise: Promise<string | undefined> | undefined;
+	async getPreviousSha(): Promise<string | undefined> {
+		if (this._previousShaPromise == null) {
+			async function getCore(this: GitCommit) {
+				if (this.file != null) {
+					if (this.file.previousSha != null && GitRevision.isSha(this.file.previousSha)) {
+						return this.file.previousSha;
+					}
+
+					const sha = await this.container.git.resolveReference(
+						this.repoPath,
+						GitRevision.isUncommitted(this.sha, true) ? 'HEAD' : `${this.sha}^`,
+						this.file.originalPath ?? this.file.path,
+					);
+					return sha;
+				}
+
+				const parent = this.parents[0];
+				if (parent != null && GitRevision.isSha(parent)) return parent;
+
+				const sha = await this.container.git.resolveReference(
+					this.repoPath,
+					GitRevision.isUncommitted(this.sha, true) ? 'HEAD' : `${this.sha}^`,
+				);
+				return sha;
+			}
+
+			this._previousShaPromise = getCore.call(this).then(sha => (this._resolvedPreviousSha = sha));
+		}
+
+		return this._previousShaPromise;
+	}
+
+	@gate()
 	async isPushed(): Promise<boolean> {
 		return this.container.git.hasCommitBeenPushed(this.repoPath, this.ref);
 	}

src/hovers/hovers.ts

@@ -20,6 +20,8 @@ export namespace Hovers {
 	): Promise<MarkdownString | undefined> {
 		const documentRef = uri.sha;
 
+		let previousSha = null;
+
 		async function getDiff() {
 			if (commit.file == null) return undefined;
 
@@ -30,7 +32,8 @@ export namespace Hovers {
 					ref = documentRef;
 				}
 			} else {
-				ref = commit.file.previousSha;
+				previousSha = await commit.getPreviousSha();
+				ref = previousSha;
 				if (ref == null) {
 					return `\`\`\`diff\n+ ${document.lineAt(editorLine).text}\n\`\`\``;
 				}
@@ -115,7 +118,9 @@ export namespace Hovers {
 				editorLine,
 			)} "Open Changes")`;
 
-			const previousSha = commit.file?.previousSha;
+			if (previousSha === null) {
+				previousSha = await commit.getPreviousSha();
+			}
 			if (previousSha) {
 				previous = `  &nbsp;[$(git-commit) ${GitRevision.shorten(
 					previousSha,

src/premium/github/githubGitProvider.ts

@@ -2151,15 +2151,21 @@ export class GitHubGitProvider implements GitProvider, Disposable {
 
 	@log()
 	async resolveReference(repoPath: string, ref: string, pathOrUri?: string | Uri, _options?: { timeout?: number }) {
-		if (!ref || ref === GitRevision.deletedOrMissing || GitRevision.isUncommitted(ref)) {
+		if (
+			!ref ||
+			ref === GitRevision.deletedOrMissing ||
+			(pathOrUri == null && GitRevision.isSha(ref)) ||
+			(pathOrUri != null && GitRevision.isUncommitted(ref))
+		) {
 			return ref;
 		}
 
 		let relativePath;
-		if (pathOrUri == null) {
-			if (GitRevision.isSha(ref) || !GitRevision.isShaLike(ref) || ref.endsWith('^3')) return ref;
-		} else {
+		if (pathOrUri != null) {
 			relativePath = this.getRelativePath(pathOrUri, repoPath);
+		} else if (!GitRevision.isShaLike(ref) || ref.endsWith('^3')) {
+			// If it doesn't look like a sha at all (e.g. branch name) or is a stash ref (^3) don't try to resolve it
+			return ref;
 		}
 
 		const context = await this.ensureRepositoryContext(repoPath);

src/views/nodes/branchTrackingStatusNode.ts

@@ -80,7 +80,8 @@ export class BranchTrackingStatusNode extends ViewNode impleme
 			// Since the last commit when we are looking 'ahead' can have no previous (because of the range given) -- look it up
 			commits = [...log.commits.values()];
 			const commit = commits[commits.length - 1];
-			if (commit.previousSha == null) {
+			const previousSha = await commit.getPreviousSha();
+			if (previousSha == null) {
 				const previousLog = await this.view.container.git.getLog(this.uri.repoPath!, {
 					limit: 2,
 					ref: commit.sha,

src/views/viewCommands.ts

@@ -1063,7 +1063,7 @@ export class ViewCommands {
 	}
 
 	@debug()
-	private openRevision(
+	private async openRevision(
 		node:
 			| CommitFileNode
 			| FileRevisionAsCommitNode
@@ -1094,7 +1094,7 @@ export class ViewCommands {
 				uri =
 					node.commit.file?.status === 'D'
 						? Container.instance.git.getRevisionUri(
-								node.commit.previousSha,
+								(await node.commit.getPreviousSha()) ?? GitRevision.deletedOrMissing,
 								node.commit.file.path,
 								node.commit.repoPath,
 						  )