refactor(generate:changeset): Condense front matter into single section

build-tools/packages/build-cli/src/commands/generate/changelog.ts

@@ -86,7 +86,7 @@ export default class GenerateChangeLogCommand extends BaseCommand<
 	/**
 	 * Removes any custom metadata from all changesets and writes the resulting changes back to the source files. This
 	 * metadata needs to be removed prior to running `changeset version` from the \@changesets/cli package. If it is not,
-	 * then the custom metadata is interpreted as part of the content and the changelogs end up with the metadata in them.
+	 * then the custom metadata is interpreted as change metadata and the changeset tools fail.
 	 *
 	 * For more information about the custom metadata we use in our changesets, see
 	 * https://github.com/microsoft/FluidFramework/wiki/Changesets#custom-metadata
@@ -113,10 +113,12 @@ export default class GenerateChangeLogCommand extends BaseCommand<
 
 		const toWrite: Promise<void>[] = [];
 		for (const changeset of changesets) {
-			const metadata = Object.entries(changeset.metadata).map((entry) => {
-				const [packageName, bump] = entry;
-				return `"${packageName}": ${bump}`;
-			});
+			// Filter out properties that start with __
+			const metadata = Object.entries(changeset.metadata)
+				.filter(([key]) => !key.startsWith("__"))
+				.map(([packageName, bump]) => {
+					return `"${packageName}": ${bump}`;
+				});
 			const output = `---\n${metadata.join("\n")}\n---\n\n${changeset.summary}\n\n${changeset.body}\n`;
 			this.info(`Writing canonical changeset: ${changeset.sourceFile}`);
 			toWrite.push(writeFile(changeset.sourceFile, output));

build-tools/packages/build-cli/src/commands/generate/changeset.ts

@@ -423,23 +423,21 @@ function createChangesetContent(
 	const frontMatterSeparator = "---";
 
 	const lines: string[] = [frontMatterSeparator];
+
+	// Add package version bumps
 	for (const [pkg, bump] of packages.entries()) {
 		lines.push(`"${pkg.name}": ${bump}`);
 	}
-	lines.push(frontMatterSeparator);
 
+	// Add Fluid-specific metadata with __ prefix
 	if (additionalMetadata !== undefined) {
-		lines.push(frontMatterSeparator);
 		for (const [name, value] of Object.entries(additionalMetadata)) {
-			lines.push(`"${name}": ${value}`);
+			lines.push(`"__${name}": ${value}`);
 		}
-		lines.push(
-			frontMatterSeparator,
-			// an extra empty line after the front matter
-			"",
-		);
 	}
 
+	lines.push(frontMatterSeparator);
+
 	const frontMatter = lines.join("\n");
 	const changesetContents = [frontMatter, body].join("\n");
 	return changesetContents;

build-tools/packages/build-cli/src/library/changesets.ts

@@ -239,21 +239,21 @@ export async function loadChangesets(dir: string, log?: Logger): Promise<Changes
 		// eslint-disable-next-line no-await-in-loop
 		const rawFileContent = await readFile(file, { encoding: "utf8" });
 
-		// Parse out the first layer of metadata, which is the package --> change type mapping.
-		const firstParse = matter(rawFileContent);
-		const packageBumpTypeMetadata = firstParse.data;
-
-		// If there is a second frontmatter section, parse it as the additional metadata.
-		const hasAdditionalMetadata = hasFrontMatter(firstParse.content);
-
-		let markdownContent: string;
-		let additionalMetadata: FluidCustomChangesetMetadata | undefined;
-		if (hasAdditionalMetadata) {
-			const secondParse = matter(firstParse.content);
-			additionalMetadata = secondParse.data;
-			markdownContent = secondParse.content.trim();
-		} else {
-			markdownContent = firstParse.content.trim();
+		// Parse the front matter
+		const { data: metadata, content: markdownContent } = matter(rawFileContent);
+
+		// Split the metadata into package version bumps and Fluid-specific metadata
+		const packageBumpTypeMetadata: { [pkg: string]: VersionBumpType } = {};
+		const additionalMetadata: FluidCustomChangesetMetadata = {};
+
+		for (const [key, value] of Object.entries(metadata)) {
+			if (key.startsWith("__")) {
+				// Remove __ prefix and add to additional metadata
+				// eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
+				additionalMetadata[key.slice(2) as keyof FluidCustomChangesetMetadata] = value;
+			} else {
+				packageBumpTypeMetadata[key] = value as VersionBumpType;
+			}
 		}
 
 		const paragraphs = markdownContent.trim().split("\n\n");
@@ -269,12 +269,12 @@ export async function loadChangesets(dir: string, log?: Logger): Promise<Changes
 		const newChangeset: Changeset = {
 			metadata: packageBumpTypeMetadata,
 			mainPackage: Object.keys(packageBumpTypeMetadata)[0],
-			additionalMetadata,
+			additionalMetadata:
+				Object.keys(additionalMetadata).length > 0 ? additionalMetadata : undefined,
 			body,
 			summary,
 			sourceFile: file,
 			commit,
-			// eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
 			changeTypes: [...new Set(Object.values(packageBumpTypeMetadata))],
 		};