Replace PR bot's diff tool with one that supports pagination

.github/workflows/manual-pull-request-bot.yml

@@ -38,11 +38,18 @@ jobs:
   # it uploads the image as a build artifact for other jobs to download and use.
   acquire-base-image:
     name: Acquire Base Image
+    needs:
+    - get-pr-info
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
       with:
         path: smithy-rs
+        # The ref used needs to match the HEAD revision of the PR being diffed, or else
+        # the `docker-build` action won't find the built Docker image. This has the unfortunate
+        # side effect that the codegen diff tool used is the one in the PR rather than in
+        # the branch this workflow was launched from.
+        ref: ${{ fromJSON(needs.get-pr-info.outputs.pull_data).head_revision }}
         fetch-depth: 0
     - name: Acquire base image
       id: acquire

.github/workflows/pull-request-bot.yml

@@ -49,6 +49,7 @@ jobs:
     - uses: actions/checkout@v3
       with:
         path: smithy-rs
+        ref: ${{ inputs.head_revision }}
     - name: Generate diff
       uses: ./smithy-rs/.github/actions/docker-build
       with:

tools/Dockerfile

@@ -11,37 +11,6 @@ ARG rust_nightly_version=nightly-2022-11-16
 
 FROM ${base_image} AS bare_base_image
 RUN yum -y updateinfo
-#
-# Node Installation Stage
-#
-FROM bare_base_image AS install_node
-ARG node_version=v16.14.0
-ENV DEST_PATH=/opt/nodejs \
-    PATH=/opt/nodejs/bin:${PATH}
-RUN yum -y install \
-        ca-certificates \
-        curl \
-        tar \
-        xz && \
-    yum clean all
-WORKDIR /root
-RUN set -eux; \
-    ARCHITECTURE=""; \
-    if [[ "$(uname -m)" == "aarch64" || "$(uname -m)" == "arm64" ]]; then \
-        curl "https://nodejs.org/dist/${node_version}/node-${node_version}-linux-arm64.tar.xz" --output node.tar.xz; \
-        echo "5a6e818c302527a4b1cdf61d3188408c8a3e4a1bbca1e3f836c93ea8469826ce  node.tar.xz" | sha256sum --check; \
-        ARCHITECTURE="arm64"; \
-    else \
-        curl "https://nodejs.org/dist/${node_version}/node-${node_version}-linux-x64.tar.xz" --output node.tar.xz; \
-        echo "0570b9354959f651b814e56a4ce98d4a067bf2385b9a0e6be075739bc65b0fae  node.tar.xz" | sha256sum --check; \
-        ARCHITECTURE="x64"; \
-    fi; \
-    mkdir -p "${DEST_PATH}"; \
-    tar -xJvf node.tar.xz -C "${DEST_PATH}"; \
-    mv "${DEST_PATH}/node-${node_version}-linux-${ARCHITECTURE}/"* "${DEST_PATH}"; \
-    rmdir "${DEST_PATH}"/node-${node_version}-linux-${ARCHITECTURE}; \
-    rm node.tar.xz; \
-    node --version
 
 #
 # Rust & Tools Installation Stage
@@ -102,6 +71,7 @@ RUN set -eux; \
     cargo +${rust_nightly_version} -Z sparse-registry install --locked --path tools/publisher; \
     cargo +${rust_nightly_version} -Z sparse-registry install --locked --path tools/changelogger; \
     cargo +${rust_nightly_version} -Z sparse-registry install --locked --path tools/crate-hasher; \
+    cargo +${rust_nightly_version} -Z sparse-registry install --locked --path tools/difftags; \
     cargo +${rust_nightly_version} -Z sparse-registry install --locked --path tools/sdk-lints; \
     cargo +${rust_nightly_version} -Z sparse-registry install --locked --path tools/sdk-versioner; \
     chmod g+rw -R /opt/cargo/registry
@@ -160,7 +130,6 @@ RUN set -eux; \
     groupadd build; \
     useradd -m -g build build; \
     chmod 775 /home/build;
-COPY --chown=build:build --from=install_node /opt/nodejs /opt/nodejs
 COPY --chown=build:build --from=local_tools /opt/cargo /opt/cargo
 COPY --chown=build:build --from=cargo_deny /opt/cargo/bin/cargo-deny /opt/cargo/bin/cargo-deny
 COPY --chown=build:build --from=cargo_udeps /opt/cargo/bin/cargo-udeps /opt/cargo/bin/cargo-udeps
@@ -169,7 +138,7 @@ COPY --chown=build:build --from=cargo_minimal_versions /opt/cargo/bin/cargo-mini
 COPY --chown=build:build --from=cargo_check_external_types /opt/cargo/bin/cargo-check-external-types /opt/cargo/bin/cargo-check-external-types
 COPY --chown=build:build --from=maturin /opt/cargo/bin/maturin /opt/cargo/bin/maturin
 COPY --chown=build:build --from=install_rust /opt/rustup /opt/rustup
-ENV PATH=/opt/cargo/bin:/opt/nodejs/bin:$PATH \
+ENV PATH=/opt/cargo/bin:$PATH \
     CARGO_HOME=/opt/cargo \
     RUSTUP_HOME=/opt/rustup \
     JAVA_HOME=/usr/lib/jvm/java-11-amazon-corretto.x86_64 \
@@ -185,7 +154,6 @@ ENV PATH=/opt/cargo/bin:/opt/nodejs/bin:$PATH \
 # This is used primarily by the `build.gradle.kts` files in choosing how to execute build tools. If inside the image,
 # they will assume the tools are on the PATH, but if outside of the image, they will `cargo run` the tools.
 ENV SMITHY_RS_DOCKER_BUILD_IMAGE=1
-RUN npm install -g diff2html-cli@5.1.11 && pip3 install --no-cache-dir uvloop==0.16.0 aiohttp==3.8.1
 WORKDIR /home/build
 COPY ci-build/scripts/sanity-test /home/build/sanity-test
 RUN /home/build/sanity-test

tools/ci-build/scripts/check-tools

@@ -25,6 +25,7 @@ function test_tool {
 test_tool "tools/changelogger" "${RUST_STABLE_VERSION}"
 test_tool "tools/ci-cdk/canary-runner" "${RUST_STABLE_VERSION}"
 test_tool "tools/crate-hasher" "${RUST_STABLE_VERSION}"
+test_tool "tools/difftags" "${RUST_STABLE_VERSION}"
 test_tool "tools/publisher" "${RUST_STABLE_VERSION}"
 test_tool "tools/sdk-lints" "${RUST_STABLE_VERSION}"
 test_tool "tools/sdk-versioner" "${RUST_STABLE_VERSION}"

tools/ci-build/scripts/sanity-test

@@ -9,10 +9,9 @@ set -eux
 cargo --version
 changelogger --version
 crate-hasher --version
-diff2html --version
+difftags --version
 git --version
 java --version
-node --version
 publisher --version
 python3 --version
 rustc +"${RUST_NIGHTLY_VERSION}" --version

tools/codegen-diff-revisions.py

@@ -35,7 +35,7 @@
 
 HEAD_BRANCH_NAME = "__tmp-localonly-head"
 BASE_BRANCH_NAME = "__tmp-localonly-base"
-OUTPUT_PATH = "tmp-codegen-diff/"
+OUTPUT_PATH = "tmp-codegen-diff"
 
 COMMIT_AUTHOR_NAME = "GitHub Action (generated code preview)"
 COMMIT_AUTHOR_EMAIL = "generated-code-action@github.com"
@@ -99,9 +99,9 @@ def generate_and_commit_generated_code(revision_sha):
     # Move generated code into codegen-diff/ directory
     run(f"rm -rf {OUTPUT_PATH}")
     run(f"mkdir {OUTPUT_PATH}")
-    run(f"mv aws/sdk/build/aws-sdk {OUTPUT_PATH}")
-    run(f"mv codegen-server-test/build/smithyprojections/codegen-server-test {OUTPUT_PATH}")
-    run(f"mv codegen-server-test/python/build/smithyprojections/codegen-server-test-python {OUTPUT_PATH}")
+    run(f"mv aws/sdk/build/aws-sdk {OUTPUT_PATH}/")
+    run(f"mv codegen-server-test/build/smithyprojections/codegen-server-test {OUTPUT_PATH}/")
+    run(f"mv codegen-server-test/python/build/smithyprojections/codegen-server-test-python {OUTPUT_PATH}/")
 
     # Clean up the server-test folder
     run(f"rm -rf {OUTPUT_PATH}/codegen-server-test/source")
@@ -120,61 +120,27 @@ def generate_and_commit_generated_code(revision_sha):
         f"commit --no-verify -m 'Generated code for {revision_sha}' --allow-empty")
 
 
-# Writes an HTML template for diff2html so that we can add contextual information
-def write_html_template(title, subtitle, tmp_file):
-    tmp_file.writelines(map(lambda line: line.encode(), [
-        "<!doctype html>",
-        "<html>",
-        "<head>",
-        '  <metadata charset="utf-8">',
-        f'  <title>Codegen diff for the {title}: {subtitle}</title>',
-        '  <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.9.0/styles/github.min.css" / >',
-        '  <!--diff2html-css-->',
-        '  <!--diff2html-js-ui-->',
-        '  <script>',
-        '  document.addEventListener("DOMContentLoaded", () => {',
-        '    const targetElement = document.getElementById("diff");',
-        '    const diff2htmlUi = new Diff2HtmlUI(targetElement);',
-        '    //diff2html-fileListToggle',
-        '    //diff2html-synchronisedScroll',
-        '    //diff2html-highlightCode',
-        '  });',
-        '  </script>',
-        "</head>",
-        "<body>",
-        f"  <h1>Codegen diff for the {title}</h1>",
-        f"  <p>{subtitle}</p>",
-        '  <div id="diff">',
-        '    <!--diff2html-diff-->',
-        '  </div>',
-        "</body>",
-        "</html>",
-    ]))
-    tmp_file.flush()
-
-
 def make_diff(title, path_to_diff, base_commit_sha, head_commit_sha, suffix, whitespace):
     whitespace_flag = "" if whitespace else "-b"
     diff_exists = get_cmd_status(f"git diff --quiet {whitespace_flag} "
                                  f"{BASE_BRANCH_NAME} {HEAD_BRANCH_NAME} -- {path_to_diff}")
     if diff_exists == 0:
-        eprint(f"No diff output for {base_commit_sha}..{head_commit_sha}")
+        eprint(f"No diff output for {base_commit_sha}..{head_commit_sha} ({suffix})")
         return None
     else:
-        run(f"mkdir -p {OUTPUT_PATH}/{base_commit_sha}/{head_commit_sha}")
-        dest_path = f"{base_commit_sha}/{head_commit_sha}/diff-{suffix}.html"
+        partial_output_path = f"{base_commit_sha}/{head_commit_sha}/{suffix}"
+        full_output_path = f"{OUTPUT_PATH}/{partial_output_path}"
+        run(f"mkdir -p {full_output_path}")
+        run(f"git diff --output=codegen-diff.txt -U30 {whitespace_flag} {BASE_BRANCH_NAME} {HEAD_BRANCH_NAME} -- {path_to_diff}")
+
+        # Generate HTML diff. This uses the `difftags` tool from the `tools/` directory.
+        # All arguments after the first `--` go to the `git diff` command.
         whitespace_context = "" if whitespace else "(ignoring whitespace)"
-        with tempfile.NamedTemporaryFile() as tmp_file:
-            write_html_template(title, f"rev. {head_commit_sha} {whitespace_context}", tmp_file)
-
-            # Generate HTML diff. This uses the diff2html-cli, which defers to `git diff` under the hood.
-            # All arguments after the first `--` go to the `git diff` command.
-            diff_cmd = f"diff2html -s line -f html -d word -i command --hwt "\
-                f"{tmp_file.name} -F {OUTPUT_PATH}/{dest_path} -- "\
-                f"-U20 {whitespace_flag} {BASE_BRANCH_NAME} {HEAD_BRANCH_NAME} -- {path_to_diff}"
-            eprint(f"Running diff cmd: {diff_cmd}")
-            run(diff_cmd)
-        return dest_path
+        subtitle = f"rev. {head_commit_sha} {whitespace_context}"
+        diff_cmd = f"difftags --output-dir {full_output_path} --title \"{title}\" --subtitle \"{subtitle}\" codegen-diff.txt"
+        eprint(f"Running diff cmd: {diff_cmd}")
+        run(diff_cmd)
+        return f"{partial_output_path}/index.html"
 
 
 def diff_link(diff_text, empty_diff_text, diff_location, alternate_text, alternate_location):