Prioritise TLDR part over the tree diff

bin/comment_with_dependency_diff

@@ -43,19 +43,20 @@ if [ "${BUILDKITE_PULL_REQUEST:-false}" == "false" ]; then
   exit 2
 fi
 
-DIFF_DEPENDENCIES_FOLDER="./build/reports/diff"
+export DIFF_DEPENDENCIES_FOLDER="./build/reports/diff"
+export COMMENT_FILE="$DIFF_DEPENDENCIES_FOLDER/comment_body.txt"
 BASE_BRANCH_DEPENDENCIES_FILE="$DIFF_DEPENDENCIES_FOLDER/base_branch_dependencies.txt"
 HEAD_BRANCH_DEPENDENCIES_FILE="$DIFF_DEPENDENCIES_FOLDER/head_branch_dependencies.txt"
 BASE_BRANCH_BUILD_ENV_FILE="$DIFF_DEPENDENCIES_FOLDER/base_branch_build_env.txt"
 HEAD_BRANCH_BUILD_ENV_FILE="$DIFF_DEPENDENCIES_FOLDER/head_branch_build_env.txt"
-DIFF_DEPENDENCIES_FILE="$DIFF_DEPENDENCIES_FOLDER/diff_dependencies.txt"
-DIFF_BUILD_ENV_FILE="$DIFF_DEPENDENCIES_FOLDER/diff_build_env.txt"
+export DIFF_DEPENDENCIES_FILE="$DIFF_DEPENDENCIES_FOLDER/diff_dependencies.txt"
+export DIFF_BUILD_ENV_FILE="$DIFF_DEPENDENCIES_FOLDER/diff_build_env.txt"
 
 DEPENDENCY_TREE_VERSION="1.2.1"
 DEPENDENCY_TREE_CHECKSUM="39c50f22cd4211a3e52afec43120b7fdf90f9890"
 
-TLDR_DIFF_DEPENDENCIES_FILE="$DIFF_DEPENDENCIES_FOLDER/tldr_diff_dependencies.txt"
-TLDR_DIFF_BUILD_ENV_FILE="$DIFF_DEPENDENCIES_FOLDER/tldr_diff_build_env.txt"
+export TLDR_DIFF_DEPENDENCIES_FILE="$DIFF_DEPENDENCIES_FOLDER/tldr_diff_dependencies.txt"
+export TLDR_DIFF_BUILD_ENV_FILE="$DIFF_DEPENDENCIES_FOLDER/tldr_diff_build_env.txt"
 
 git config --global user.email "mobile@automattic.com"
 git config --global user.name "Dependency Tree Diff Tool"
@@ -121,90 +122,15 @@ java -jar "$JAR_DIR/dependency-diff-tldr-0.0.6.jar" $BASE_BRANCH_DEPENDENCIES_FI
 ./dependency-tree-diff.jar $BASE_BRANCH_BUILD_ENV_FILE $HEAD_BRANCH_BUILD_ENV_FILE >$DIFF_BUILD_ENV_FILE
 java -jar "$JAR_DIR/dependency-diff-tldr-0.0.6.jar" $BASE_BRANCH_BUILD_ENV_FILE $HEAD_BRANCH_BUILD_ENV_FILE >$TLDR_DIFF_BUILD_ENV_FILE
 
-generate_project_dependencies_comment_body() {
-  cat <<EOF
+echo "--> Preparing comment for GitHub"
 
-The following changes in project dependencies were detected (configuration \`$CONFIGURATION\`):
-
-<details><summary>list</summary>
-
-\`\`\`
-$(cat "$TLDR_DIFF_DEPENDENCIES_FILE")
-\`\`\`
-
-</details>
-
-<details><summary>tree</summary>
-
-\`\`\`diff
-$(cat "$DIFF_DEPENDENCIES_FILE")
-\`\`\`
-
-</details>
-
-
-EOF
-}
-
-generate_build_dependencies_comment_body() {
-  cat <<EOF
-
-The following changes in the build classpath were detected:
-
-<details><summary>list</summary>
-
-\`\`\`
-$(cat "$TLDR_DIFF_BUILD_ENV_FILE")
-\`\`\`
-
-</details>
-
-<details><summary>tree</summary>
-
-\`\`\`diff
-$(cat "$DIFF_BUILD_ENV_FILE")
-\`\`\`
-
-</details>
-
-EOF
-}
-
-if [ -n "$DIFF_DEPENDENCIES_FILE" ] || [ -n "$DIFF_BUILD_ENV_FILE" ]; then
-  echo "--> Commenting result to GitHub"
-
-  # Create or clear the comment body file
-  COMMENT_FILE="$DIFF_DEPENDENCIES_FOLDER/comment_body.txt"
-  true > $COMMENT_FILE  # 'true' used to clear the file as a no-op
-
-  append_content() {
-    local header="$1"
-    local content="$2"
-    local github_comment_max_size=65400 # GitHub constraint is 65536, but we decrease this value slightly to reserve for hidden comment_on_pr content and line breaks
-    local warning_message="Content exceeds $github_comment_max_size characters. [Navigate to Buildkite build artifacts](${BUILDKITE_BUILD_URL}#${BUILDKITE_JOB_ID}) to see details."
-
-    local current_size
-    current_size=$(wc -c < "$COMMENT_FILE")
-
-    # Calculate if there's enough space for the content and header
-    if (( current_size + ${#header} + ${#content} > github_comment_max_size - ${#header} - ${#warning_message})); then
-      printf "\n%s\n%s\n" "$header" "$warning_message" > $COMMENT_FILE
-      return
-    fi
-
-    printf "\n%s\n" "$header" >> $COMMENT_FILE
-    printf "%s\n" "$content" >> $COMMENT_FILE
-  }
-
-  if [ -s "$DIFF_DEPENDENCIES_FILE" ]; then
-    append_content "## Project dependencies changes" "$(generate_project_dependencies_comment_body)"
-  fi
+# Check if any dependency changes were found
+if [ ! -s "$TLDR_DIFF_DEPENDENCIES_FILE" ] && [ ! -s "$TLDR_DIFF_BUILD_ENV_FILE" ]; then
+    echo "No dependency changes found"
+    comment_on_pr --id "dependency-diff" --if-exist delete
+    exit 0
+fi
 
-  if [ -s "$DIFF_BUILD_ENV_FILE" ]; then
-    append_content "## Build environment changes" "$(generate_build_dependencies_comment_body)"
-  fi
+craft_comment_with_dependency_diff
 
-  comment_on_pr --id "dependency-diff" --if-exist update "$COMMENT_FILE"
-else
-  comment_on_pr --id "dependency-diff" --if-exist delete
-fi
+comment_on_pr --id "dependency-diff" --if-exist update "$COMMENT_FILE"

bin/craft_comment_with_dependency_diff

@@ -0,0 +1,78 @@
+#!/bin/bash
+# shellcheck disable=SC2059
+
+# This script is used to craft a comment with a dependency diff and a build environment diff.
+# It's extracted from comment_with_dependency_diff to be tested in isolation.
+
+set -euo pipefail
+
+true > "$COMMENT_FILE"  # Clear the file
+MAX_COMMENT_SIZE=65400
+current_size=0
+
+# Templates for content formatting
+SECTION_HEADER="## %s changes\n\n"
+TLDR_TEMPLATE="<details><summary>list</summary>
+
+\`\`\`
+%s
+\`\`\`
+
+</details>
+"
+TREE_TEMPLATE="<details><summary>tree</summary>
+
+\`\`\`diff
+%s
+\`\`\`
+
+</details>"
+TREE_TOO_LARGE="\n ⚠️ %s tree is too large. [View it in Buildkite artifacts](%s#%s)\n"
+
+# Calculate total size needed for TLDRs
+# This assumes that TLDRs are never too large to fit in the comment
+tldr_size=0
+for section in "Project dependencies" "Build environment"; do
+    tldr_file="$TLDR_DIFF_DEPENDENCIES_FILE"
+    [[ $section == "Build environment" ]] && tldr_file="$TLDR_DIFF_BUILD_ENV_FILE"
+
+    if [ -s "$tldr_file" ]; then
+        content=$(printf "$SECTION_HEADER$TLDR_TEMPLATE" "$section" "$(cat "$tldr_file")")
+        tldr_size=$(( tldr_size + ${#content} ))
+    fi
+done
+
+# Function to check if content would fit
+would_content_fit() {
+    if (( current_size + $1 < MAX_COMMENT_SIZE )); then
+        return 0  # Success/true - content will fit
+    else
+        return 1  # Failure/false - content won't fit
+    fi
+}
+
+# Print content in order
+for section in "Project dependencies" "Build environment"; do
+    tldr_file="$TLDR_DIFF_DEPENDENCIES_FILE"
+    tree_file="$DIFF_DEPENDENCIES_FILE"
+    [[ $section == "Build environment" ]] && tldr_file="$TLDR_DIFF_BUILD_ENV_FILE" && tree_file="$DIFF_BUILD_ENV_FILE"
+
+    if [ -s "$tldr_file" ]; then
+        # Print section header and TLDR
+        printf "$SECTION_HEADER" "$section" >> "$COMMENT_FILE"
+        printf "$TLDR_TEMPLATE" "$(cat "$tldr_file")" >> "$COMMENT_FILE"
+        current_size=$(wc -c < "$COMMENT_FILE")
+
+        # Try to add tree if it exists
+        if [ -s "$tree_file" ]; then
+            tree_content=$(cat "$tree_file")
+            content=$(printf "$TREE_TEMPLATE" "$tree_content")
+            if would_content_fit ${#content}; then
+                echo -e "$content" >> "$COMMENT_FILE"
+                current_size=$(wc -c < "$COMMENT_FILE")
+            else
+                printf "$TREE_TOO_LARGE" "$section" "$BUILDKITE_BUILD_URL" "$BUILDKITE_JOB_ID" >> "$COMMENT_FILE"
+            fi
+        fi
+    fi
+done

tests/test_craft_comment_with_dependency_diff.bats

@@ -0,0 +1,108 @@
+#!/usr/bin/env bats
+
+setup() {
+    # Get the directory of the test file
+    DIR="$( cd "$( dirname "$BATS_TEST_FILENAME" )" >/dev/null 2>&1 && pwd )"
+
+    # Create a temporary directory for test artifacts
+    export TEMP_DIR="$(mktemp -d)"
+    export DIFF_DEPENDENCIES_FOLDER="$TEMP_DIR"
+    export COMMENT_FILE="$DIFF_DEPENDENCIES_FOLDER/comment_body.txt"
+    export TLDR_DIFF_DEPENDENCIES_FILE="$TEMP_DIR/tldr_dependencies.txt"
+    export TLDR_DIFF_BUILD_ENV_FILE="$TEMP_DIR/tldr_build_env.txt"
+    export DIFF_DEPENDENCIES_FILE="$TEMP_DIR/dependencies.txt"
+    export DIFF_BUILD_ENV_FILE="$TEMP_DIR/build_env.txt"
+
+    # Mock Buildkite environment variables
+    export BUILDKITE_BUILD_URL="https://buildkite.com/test/build"
+    export BUILDKITE_JOB_ID="job123"
+}
+
+teardown() {
+    rm -rf "$TEMP_DIR"
+}
+
+@test "should create comment with both TLDRs and trees when content is small" {
+    # Create test dependency files with small content
+    echo "org.test:library:2.0.0 (from 1.0.0)" > "$TLDR_DIFF_DEPENDENCIES_FILE"
+    echo "org.test:build-tool:3.0.0 (from 2.0.0)" > "$TLDR_DIFF_BUILD_ENV_FILE"
+
+    echo "+org.test:library:2.0.0
+-org.test:library:1.0.0" > "$DIFF_DEPENDENCIES_FILE"
+
+    echo "+org.test:build-tool:3.0.0
+-org.test:build-tool:2.0.0" > "$DIFF_BUILD_ENV_FILE"
+
+    # Run the script
+    run "$DIR/../bin/craft_comment_with_dependency_diff"
+
+    # Assert success
+    [ "$status" -eq 0 ]
+
+    # Read generated comment
+    local comment_content=$(<"$COMMENT_FILE")
+
+    # Assert both sections are present
+    [[ "$comment_content" =~ "## Project dependencies changes" ]]
+    [[ "$comment_content" =~ "## Build environment changes" ]]
+
+    # Assert both TLDRs are present
+    [[ "$comment_content" =~ "org.test:library:2.0.0 (from 1.0.0)" ]]
+    [[ "$comment_content" =~ "org.test:build-tool:3.0.0 (from 2.0.0)" ]]
+
+    # Assert both trees are present
+    [[ "$comment_content" =~ "+org.test:library:2.0.0" ]]
+    [[ "$comment_content" =~ "+org.test:build-tool:3.0.0" ]]
+
+    # Assert no "too large" warnings
+    [[ ! "$comment_content" =~ "tree is too large" ]]
+}
+
+@test "should handle mixed tree sizes with large project dependencies" {
+    # Create large project dependencies tree
+    echo "org.test:library:2.0.0 (from 1.0.0)" > "$TLDR_DIFF_DEPENDENCIES_FILE"
+
+    # Generate a large tree for project dependencies
+    local large_tree=""
+    for i in {1..1100}; do
+        large_tree+="+org.test:large-lib-${i}:2.0.0
+-org.test:large-lib-${i}:1.0.0
+"
+    done
+    echo "$large_tree" > "$DIFF_DEPENDENCIES_FILE"
+
+    # Create small build environment changes
+    echo "org.test:build-tool:3.0.0 (from 2.0.0)" > "$TLDR_DIFF_BUILD_ENV_FILE"
+    echo "+org.test:build-tool:3.0.0
+-org.test:build-tool:2.0.0" > "$DIFF_BUILD_ENV_FILE"
+
+    # Run the script
+    run "$DIR/../bin/craft_comment_with_dependency_diff"
+
+    # Assert success
+    [ "$status" -eq 0 ]
+
+    # Read generated comment
+    local comment_content=$(<"$COMMENT_FILE")
+
+    echo "$comment_content";
+
+    # Assert both sections are present
+    [[ "$comment_content" =~ "## Project dependencies changes" ]]
+    [[ "$comment_content" =~ "## Build environment changes" ]]
+
+    # Assert both TLDRs are present
+    [[ "$comment_content" =~ "org.test:library:2.0.0 (from 1.0.0)" ]]
+    [[ "$comment_content" =~ "org.test:build-tool:3.0.0 (from 2.0.0)" ]]
+
+    # Assert small build environment tree is present
+    [[ "$comment_content" =~ "+org.test:build-tool:3.0.0" ]]
+    [[ "$comment_content" =~ "-org.test:build-tool:2.0.0" ]]
+
+    # Assert large project dependencies tree is replaced with warning
+    [[ "$comment_content" =~ "Project dependencies tree is too large" ]]
+    [[ "$comment_content" =~ "View it in Buildkite artifacts" ]]
+
+    # Assert only one "too large" warning
+    [[ ! "$comment_content" =~ "Build environment tree is too large" ]]
+}