Weekly GitHub Report for Mermaid

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Table of Contents

• I. News
  • 1.1. Recent Version Releases
  • 1.2. Other Noteworthy Updates
• II. Issues
  • 2.1. Top 5 Active Issues
  • 2.2. Top 5 Stale Issues
  • 2.3. Open Issues
  • 2.4. Closed Issues
  • 2.5. Issue Discussion Insights

• III. Pull Requests
  • 3.1. Open Pull Requests
  • 3.2. Closed Pull Requests
  • 3.3. Pull Request Discussion Insights

• IV. Contributors
  • 4.1. Contributors

I. News

1.1 Recent Version Releases:

The current version of this repository is @mermaid-js/parser@0.4.0

1.2 Version Information:

On March 25, 2025, a minor update was released that introduced the addition of a Radar Chart feature, enhancing the charting capabilities of the platform. This update reflects ongoing efforts to expand visualization options.

II. Issues

2.1 Top 5 Active Issues:

We consider active issues to be issues that that have been commented on most frequently within the last week. Bot comments are omitted.

1. [TYPE: BUG / ERROR] [STATUS: TRIAGE] Arrows between subgraphs are broken since 11.16.0 (direction statement in subgraph): This issue reports that arrows between elements of subgraphs in flowcharts are broken starting from version 11.16.0 when a direction statement is used inside a subgraph, causing the connections to render incorrectly compared to version 11.15.0. The user provides a minimal reproducible example demonstrating the problem and confirms through discussion that removing the direction statement inside the subgraph resolves the issue.

   • The comments identify a duplicate issue and narrow down the bug to subgraphs containing the direction statement; the user confirms that removing the direction from the subgraph fixes the arrow rendering problem.
   • Number of comments this week: 2

2. [TYPE: ENHANCEMENT] [GRAPH: FLOW] [STATUS: IN PROGRESS] Note in flowchart diagram: This issue requests the ability to add notes directly within flowchart diagrams in Mermaid, similar to features available in Gantt or sequence diagrams, to provide additional context or explanations beside nodes. Users have discussed potential syntax and workarounds, such as using hidden subgraphs or footnotes, and expressed strong interest in having a native, clean solution for annotating flowcharts to improve clarity and usability.

   • The comments include suggestions for implementing notes using hidden subgraphs or syntax inspired by PlantUML, multiple users expressing enthusiasm and providing workarounds, ongoing interest in the feature, and some discussion about related diagram types and annotation methods, with no final solution yet but active development indicated.
   • Number of comments this week: 1

3. [TYPE: BUG / ERROR] [CONTRIBUTOR NEEDED] [STATUS: APPROVED] [GRAPH: FLOW] Multiline title in flowchart subgraphs is overlapped by nodes: This issue addresses the problem where multiline titles in flowchart subgraphs are overlapped by nodes, making the titles partially unreadable and reducing the clarity of the diagram's semantic grouping. It highlights the lack of control over spacing such as margin and padding for subgraph titles, which affects the visual and architectural communication in Mermaid diagrams, especially in common use cases like GitHub Markdown rendering.

   • The comments discuss potential solutions including placing labels on top of bounding boxes, using invisible nodes as workarounds, and CSS tweaks; users express strong interest in a fix, share practical impacts, and note ongoing efforts with a pull request targeting the Dagre layout to reserve space for multiline titles and prevent overlap.
   • Number of comments this week: 1

4. [TYPE: ENHANCEMENT] [STATUS: TRIAGE] Add actor symbol from sequence diagrams to Flowcharts : This issue proposes adding the actor symbol used in sequence diagrams to flowcharts in Mermaid, as users often need to represent an actor, user, or person visually, which is currently approximated using a trapezoid with a fontawesome user icon. The request highlights that while the actor symbol is not a standard flowchart symbol, incorporating it would improve clarity and consistency when depicting actors across different diagram types.

   • The comments include a request for clarification, an explanation that the issue is about adding the actor symbol from sequence diagrams to flowcharts, a note on actors being common symbols in data flow diagrams representing humans, a suggestion to allow custom SVG icons for actors or participants, and a concern about the project's maintenance status.
   • Number of comments this week: 1

5. [STATUS: TRIAGE] C4 diagrams: unified renderer migration and c4-beta - PR series tracker: This issue tracks the comprehensive modernization of the C4 diagram renderer in the Mermaid project, aiming to replace the legacy row-grid renderer with a unified rendering pipeline that supports real layout engines, themes, tags, icons, links, and legends, alongside introducing a new structurizr-inspired c4-beta syntax. The migration is organized into phased pull requests that incrementally update rendering layers (shapes, edges, layout) and add new features, ensuring backward compatibility and convergence on a single visual language confirmed by the original C4 creator, Simon Brown.

   • The comments provide detailed progress updates on the phased PRs, including feedback from Simon Brown that shaped the c4-beta syntax, status reports on merges and reviews, and clarifications on the migration strategy; the discussion emphasizes careful batching of changes, visual proof galleries for review without CI credits, and readiness for maintainers to proceed with the next merges.
   • Number of comments this week: 1

2.2 Top 5 Stale Issues:

We consider stale issues to be issues that has had no activity within the last 30 days. The team should work together to get these issues resolved and closed as soon as possible.

As of our latest update, there are no stale issues for the project this week.

2.3 Open Issues

This section lists, groups, and then summarizes issues that were created within the last week in the repository.

Issues Opened This Week: 7

Summarized Issues:

• Subgraph rendering and direction issues: Multiple issues report problems with edges and arrows in subgraphs not rendering correctly, including edges pointing to the subgraph itself instead of nodes and broken connections when direction statements are used inside subgraphs. These bugs affect the visual correctness of flowcharts and subgraph layouts, causing inconsistencies between versions and failure to inherit top-level graph direction settings.
• issues/7946, issues/7954

• Text wrapping and label character restrictions: There are issues with text wrapping in C4 diagrams where the wrap flag is frozen to false, preventing multi-line text regardless of configuration, and with the architecture-beta diagram type rejecting non-ASCII and certain punctuation characters in labels due to restrictive regex patterns. These problems limit diagram readability and usability, especially for internationalization and complex label content.
• issues/7949, issues/7961

• Console warnings from minified code: Loading the latest mermaid.min.js triggers a Firefox DevTools warning about unreachable code caused by dead code in a minified internal helper, which does not affect functionality but creates unnecessary console noise visible only in Firefox. This issue impacts developer experience by cluttering the console with warnings during debugging.
• issues/7953

• Swimlane readability problems: Swimlanes become difficult to read when titles are long and many connections exist, causing excessive spacing and forcing nodes into a single line, which reduces the overall readability compared to regular flowchart groups. This issue affects the clarity and usability of swimlane diagrams with complex or verbose content.
• issues/7964

• Request for native Venn diagram support: There is a proposal to add native Venn diagram support to Mermaid to better represent set relationships and classifications, which are currently unsupported but important for fields like computer science, mathematics, and education. This feature request aims to expand Mermaid's diagram capabilities for clearer conceptual visualization.
• issues/7967

2.4 Closed Issues

This section lists, groups, and then summarizes issues that were closed within the last week in the repository. This section also links the associated pull requests if applicable.

Issues Closed This Week: 5

Summarized Issues:

• Documentation and Feature Presentation: The README currently lacks a clear presentation of Mermaid's capabilities, which limits users' understanding of the tool's functionalities. Adding a new Features section is proposed to highlight key functionalities and benefits, improving overall documentation clarity.
• issues/7665

• Rendering and Layout Configuration Issues: There is a problem where nodeSpacing and rankSpacing settings for certain diagrams are ignored due to flowchart defaults taking precedence in the dagre layout, causing user-defined spacing values to have no effect. A fix is proposed to reorder precedence so explicit top-level configuration values override flowchart defaults, ensuring intended layout behavior.
• issues/7932

• New Application Development: A user announced the development of a Mermaid app supporting markdown, mermaid, and LaTeX, which is currently available only in Chinese and on Android. The announcement includes download links for the app, expanding the ecosystem of Mermaid tools.
• issues/7939

• Complex Flowchart Use Case: A detailed flowchart diagram was created to illustrate the step-by-step process for citizens and police officers in the application, verification, and issuance of identification cards, covering both direct and online submissions, system automation, and final card delivery. This demonstrates Mermaid's capability to handle complex, real-world procedural diagrams.
• issues/7960

• Subgraph Direction Bug: Setting the "direction" property inside a subgraph in a Mermaid flowchart breaks links between nodes inside and outside the subgraph, a bug introduced in version 11.16.0 but absent in 11.15.0. This issue affects diagram integrity and requires a fix to restore proper link behavior.
• issues/7965

2.5 Issue Discussion Insights

This section will analyze the tone and sentiment of discussions within this project's open and closed issues that occurred within the past week. It aims to identify potentially heated exchanges and to maintain a constructive project environment.

Based on our analysis, there are no instances of toxic discussions in the project's open or closed issues from the past week.

III. Pull Requests

3.1 Open Pull Requests

This section provides a summary of pull requests that were opened in the repository over the past week. The top three pull requests with the highest number of commits are highlighted as 'key' pull requests. Other pull requests are grouped based on similar characteristics for easier analysis. Up to 25 pull requests are displayed in this section, while any remaining pull requests beyond this limit are omitted for brevity.

Pull Requests Opened This Week: 11

Key Open Pull Requests

1. feat(gitGraph): add multi parent merge: This pull request adds support for octopus (multi-parent) merges in the gitGraph feature of Mermaid by updating the parser, database, and merge logic to allow a single merge commit node to have multiple parent branches, including validation rules, improved commit message formatting, and corresponding unit tests and demos.

• URL: pull/7950

• Associated Commits: 22a50, 6c95e, 74b15, 07850, 12e16

2. perf: use the fastdom library to avoid unnecessary reflows: This pull request improves Mermaid's rendering performance by integrating the fastdom library to batch DOM measurements and updates, thereby reducing layout thrashing and unnecessary reflows in key label rendering functions, resulting in up to 25–30% faster rendering in large flowcharts.

• URL: pull/7951

• Associated Commits: b9fc2, 974d3, 1795c

3. Fix ELK link in layouts documentation: This pull request updates the Mermaid "Supported Layouts" documentation by changing the ELK hyperlink to the new domain https://eclipse.dev/elk/, replacing the previous https://www.eclipse.org/elk/, without modifying any other content.

• URL: pull/7952

• Associated Commits: 18155, dc433

Other Open Pull Requests

• Documentation improvements: These pull requests enhance and correct documentation references and expand existing minimal stubs into comprehensive references. One expands the layouts.md documentation to cover all layout algorithms in Mermaid with detailed ELK layout information, while another fixes a broken reference link for the initialize() call in the syntax reference documentation.
  [pull/7955, pull/7963]

• Bug fixes in rendering and parsing: Multiple pull requests address rendering and parsing issues across different Mermaid diagram types. Fixes include supporting nested generic types in class diagrams by improving the lexer and formatting, resolving Firefox-specific SVG image sizing bugs in flowcharts, correcting <br/> line break handling in flowchart labels with KaTeX math, and fixing nested composite state rendering errors in state diagrams by preserving parent relationships and handling empty composite bodies.
  [pull/7957, pull/7958, pull/7962, pull/7959]

• Test coverage and CI configuration reverts: These pull requests revert previous changes related to test coverage collection and end-to-end test scoping. One restores the Cypress and Istanbul-based coverage setup instead of native V8 to maintain Electron compatibility, and another disables default E2E scoping for forked pull requests to prevent Argos build queue issues.
  [pull/7947, pull/7948]

3.2 Closed Pull Requests

This section provides a summary of pull requests that were closed in the repository over the past week. The top three pull requests with the highest number of commits are highlighted as 'key' pull requests. Other pull requests are grouped based on similar characteristics for easier analysis. Up to 25 pull requests are displayed in this section, while any remaining pull requests beyond this limit are omitted for brevity.

Pull Requests Closed This Week: 3

Key Closed Pull Requests

1. test(c4): characterization suite + feature matrix: This pull request adds a comprehensive C4 characterization test suite and a feature matrix to capture the current renderer's output as a visual-regression baseline across all C4 grammar features, enabling explicit tracking of visual changes during the planned migration to a unified renderer without altering the published renderer's behavior.

• URL: pull/7876

• Associated Commits: 9fc30, e5a7e, 70617, 7a7f4, d5077, 04a33, 9254b

• Associated Commits: 9fc30, e5a7e, 70617, 7a7f4, d5077, 04a33, 9254b

2. Add features section to README: This pull request adds a detailed Features section to the README.md file of the Mermaid project, providing a clear and updated overview of the tool’s capabilities, including a list of over 20 supported diagram types, corrected project statistics, and emphasizing key strengths such as Markdown-inspired syntax, live editing, and community momentum, all as a documentation-only enhancement.

• URL: pull/7944

• Associated Commits: 52965, 2e3a6

• Associated Commits: 52965, 2e3a6

3. fix(layout): let a diagram's own nodeSpacing/rankSpacing win over flowchart defaults in the unified dagre layout: This pull request fixes the unified dagre layout in the Mermaid project to ensure that a diagram's own nodeSpacing and rankSpacing settings correctly override the default flowchart spacing values, by adjusting the precedence order in the configuration resolution so that diagram-specific spacing values are honored as intended.

• URL: pull/7937

• Associated Commits: f9cbe

• Associated Commits: f9cbe

3.3 Pull Request Discussion Insights

This section will analyze the tone and sentiment of discussions within this project's open and closed pull requests that occurred within the past week. It aims to identify potentially heated exchanges and to maintain a constructive project environment.

Based on our analysis, there are no instances of toxic discussions in the project's open or closed pull requests from the past week.

IV. Contributors

4.1 Contributors

Active Contributors:

We consider an active contributor in this project to be any contributor who has made at least 1 commit, opened at least 1 issue, created at least 1 pull request, or made more than 2 comments in the last month.

If there are more than 10 active contributors, the list is truncated to the top 10 based on contribution metrics for better clarity.

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