ci: store last-modified timestamps in Github Actions cache (#10110)

5 files changed, 246 insertions, 2 deletions

diff --git a/.github/mtime_cache/action.js b/.github/mtime_cache/action.js
new file mode 100644
index 000000000..ffc7caa7e
--- /dev/null
+++ b/.github/mtime_cache/action.js
@@ -0,0 +1,215 @@
+// This file contains the implementation of a Github Action. Github uses
+// Node.js v12.x to run actions, so this is Node code and not Deno code.
+
+const { spawn } = require("child_process");
+const { dirname, resolve } = require("path");
+const { StringDecoder } = require("string_decoder");
+const { promisify } = require("util");
+
+const fs = require("fs");
+const utimes = promisify(fs.utimes);
+const mkdir = promisify(fs.mkdir);
+const readFile = promisify(fs.readFile);
+const writeFile = promisify(fs.writeFile);
+
+process.on("unhandledRejection", abort);
+main().catch(abort);
+
+async function main() {
+  const startTime = getTime();
+
+  const checkCleanPromise = checkClean();
+
+  const cacheFile = getCacheFile();
+  const oldCache = await loadCache(cacheFile);
+  const newCache = Object.create(null);
+
+  await checkCleanPromise;
+
+  const counters = {
+    restored: 0,
+    added: 0,
+    stale: 0,
+    invalid: 0,
+  };
+
+  for await (const { key, path } of ls()) {
+    let mtime = oldCache[key];
+    if (mtime === undefined) {
+      mtime = startTime;
+      counters.added++;
+    } else if (!mtime || mtime > startTime) {
+      mtime = startTime;
+      counters.invalid++;
+    } else {
+      counters.restored++;
+    }
+
+    await utimes(path, startTime, mtime);
+    newCache[key] = mtime;
+  }
+
+  for (const key of Object.keys(oldCache)) {
+    if (!(key in newCache)) counters.stale++;
+  }
+
+  await saveCache(cacheFile, newCache);
+
+  const stats = {
+    ...counters,
+    "cache file": cacheFile,
+    "time spent": (getTime() - startTime).toFixed(3) + "s",
+  };
+  console.log(
+    [
+      "mtime cache statistics",
+      ...Object.entries(stats).map(([k, v]) => `* ${k}: ${v}`),
+    ].join("\n"),
+  );
+}
+
+function abort(err) {
+  console.error(err);
+  process.exit(1);
+}
+
+function getTime() {
+  return Date.now() / 1000;
+}
+
+function getCacheFile() {
+  const cachePath = process.env["INPUT_CACHE-PATH"];
+  if (cachePath == null) {
+    throw new Error("required input 'cache_path' not provided");
+  }
+
+  const cacheFile = resolve(cachePath, ".mtime-cache-db.json");
+  return cacheFile;
+}
+
+async function loadCache(cacheFile) {
+  try {
+    const json = await readFile(cacheFile, { encoding: "utf8" });
+    return JSON.parse(json);
+  } catch (err) {
+    if (err.code !== "ENOENT") {
+      console.warn(`failed to load mtime cache from '${cacheFile}': ${err}`);
+    }
+    return Object.create(null);
+  }
+}
+
+async function saveCache(cacheFile, cacheData) {
+  const cacheDir = dirname(cacheFile);
+  await mkdir(cacheDir, { recursive: true });
+
+  const json = JSON.stringify(cacheData, null, 2);
+  await writeFile(cacheFile, json, { encoding: "utf8" });
+}
+
+async function checkClean() {
+  let output = run(
+    "git",
+    [
+      "status",
+      "--porcelain=v1",
+      "--ignore-submodules=untracked",
+      "--untracked-files=no",
+    ],
+    { stdio: ["ignore", "pipe", "inherit"] },
+  );
+  output = decode(output, "utf8");
+  output = split(output, "\n");
+  output = filter(output, Boolean);
+  output = await collect(output);
+
+  if (output.length > 0) {
+    throw new Error(
+      ["git work dir dirty", ...output.map((f) => `  ${f}`)].join("\n"),
+    );
+  }
+}
+
+async function* ls(dir = "") {
+  let output = run(
+    "git",
+    ["-C", dir || ".", "ls-files", "--stage", "--eol", "--full-name", "-z"],
+    { stdio: ["ignore", "pipe", "inherit"] },
+  );
+  output = decode(output, "utf8");
+  output = split(output, "\0");
+  output = filter(output, Boolean);
+
+  for await (const entry of output) {
+    const pat =
+      /^(?<mode>\d{6}) (?<hash>[0-9a-f]{40}) 0\t(?<eol>[^\t]*?)[ ]*\t(?<name>.*)$/;
+    const { mode, hash, eol, name } = pat.exec(entry).groups;
+    const path = dir ? `${dir}/${name}` : name;
+
+    switch (mode) {
+      case "120000": // Symbolic link.
+        break;
+      case "160000": // Git submodule.
+        yield* ls(path);
+        break;
+      default: {
+        // Regular file.
+        const key = [mode, hash, eol, path].join("\0");
+        yield { key, path };
+      }
+    }
+  }
+}
+
+async function* run(cmd, args, options) {
+  const child = spawn(cmd, args, options);
+
+  const promise = new Promise((resolve, reject) => {
+    child.on("close", (code, signal) => {
+      if (code === 0 && signal === null) {
+        resolve();
+      } else {
+        const command = [cmd, ...args].join(" ");
+        const how = signal === null ? `exit code ${code}` : `signal ${signal}`;
+        const error = new Error(`Command '${command}' failed: ${how}`);
+        reject(error);
+      }
+    });
+    child.on("error", reject);
+  });
+
+  yield* child.stdout;
+  await promise;
+}
+
+async function collect(stream) {
+  const array = [];
+  for await (const item of stream) {
+    array.push(item);
+  }
+  return array;
+}
+
+async function* decode(stream, encoding) {
+  const decoder = new StringDecoder(encoding);
+  for await (const chunk of stream) {
+    yield decoder.write(chunk);
+  }
+  yield decoder.end();
+}
+
+async function* filter(stream, fn) {
+  for await (const item of stream) {
+    if (fn(item)) yield item;
+  }
+}
+
+async function* split(stream, separator) {
+  let buf = "";
+  for await (const chunk of stream) {
+    const parts = (buf + chunk).split(separator);
+    buf = parts.pop();
+    yield* parts.values();
+  }
+  yield buf;
+}
diff --git a/.github/mtime_cache/action.yml b/.github/mtime_cache/action.yml
new file mode 100644
index 000000000..20e7b251f
--- /dev/null
+++ b/.github/mtime_cache/action.yml
@@ -0,0 +1,10 @@
+name: mtime cache
+description:
+  Preserve last-modified timestamps by storing them in the Github Actions cache
+inputs:
+  cache-path:
+    description: Path where the mtime cache database should be located
+    required: true
+runs:
+  main: action.js
+  using: node12
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a341c4a59..1ad068ed5 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -44,7 +44,6 @@ jobs:
         'refs/heads/main' && !startsWith(github.ref, 'refs/tags/')) }}
 
     env:
-      CARGO_INCREMENTAL: 0
       RUST_BACKTRACE: full
       CARGO_TERM_COLOR: always
 
@@ -59,7 +58,7 @@ jobs:
           # other commits have landed it will become impossible to rebuild if
           # the checkout is too shallow.
           fetch-depth: 5
-          submodules: true
+          submodules: recursive
 
       - name: Create source tarballs (release, linux)
         if: |
@@ -168,6 +167,23 @@ jobs:
           brew install gnu-tar
           echo "/usr/local/opt/gnu-tar/libexec/gnubin" >> $GITHUB_PATH
 
+      - name: Cache
+        uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cargo/git
+            ~/.cargo/registry
+            ./target
+          key:
+            ${{ matrix.os }}-${{ matrix.kind }}-${{ hashFiles('Cargo.lock') }}
+          restore-keys: |
+            ${{ matrix.os }}-${{ matrix.kind }}-
+
+      - name: Apply and update mtime cache
+        uses: ./.github/mtime_cache
+        with:
+          cache-path: ./target
+
       - name: test_format.js
         if: matrix.kind == 'lint'
         run: deno run --unstable --allow-write --allow-read --allow-run ./tools/format.js --check
diff --git a/Cargo.toml b/Cargo.toml
index 4d7c8be95..d99f66fd3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -23,11 +23,13 @@ exclude = [
 
 [profile.release]
 codegen-units = 1
+incremental = true
 lto = true
 opt-level = 'z' # Optimize for size
 
 [profile.bench]
 codegen-units = 1
+incremental = true
 lto = true
 opt-level = 'z' # Optimize for size
 
diff --git a/tools/lint.js b/tools/lint.js
index 7e2e57d2c..299632d90 100755
--- a/tools/lint.js
+++ b/tools/lint.js
@@ -16,6 +16,7 @@ async function dlint() {
   const sourceFiles = await getSources(ROOT_PATH, [
     "*.js",
     "*.ts",
+    ":!:.github/mtime_cache/action.js",
     ":!:cli/tests/swc_syntax_error.ts",
     ":!:cli/tests/038_checkjs.js",
     ":!:cli/tests/error_008_checkjs.js",