Cannot read properties of undefined (reading 'startIndex')

[maximelets]

Self-Troubleshooting Checklist

• Are you running Prettier Apex >= 2.0.0? If Yes, have you gone through the Upgrade Guide?
• Are you running VSCode and recently upgraded Prettier or Prettier Apex? If Yes, have you restarted VSCode after the upgrade?

Describe your issue

While running formatting it returns me back following error:

TypeError: Cannot read properties of undefined (reading 'startIndex')
at locStart (node_modules/prettier-plugin-apex/dist/src/index.js:24:21)
at nodeContainsCursor (node_modules/prettier/index.mjs:20212:40)
at isMatchedNode (node_modules/prettier/index.mjs:18792:64)
at getChildren (node_modules/prettier/index.mjs:18801:16)
at getChildren.next ()
at getDescendants (node_modules/prettier/index.mjs:18810:16)
at getDescendants.next ()
at getCursorLocation (node_modules/prettier/index.mjs:20215:14)
at coreFormat (node_modules/prettier/index.mjs:20535:10)
at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
Process finished with exit code -1

I'm using Webstorm + Illuminated Cloud plugin.

Issues started to happen after updates.

I already did install of all of the dependencies from the scratch.(Removed node_modules, updated node.js, updated java to 24v and etc).

Prettier options (if any)

{
    "printWidth": 160,
    "tabWidth": 4,
    "useTabs": false,
    "semi": true,
    "singleQuote": true,
    "quoteProps": "as-needed",
    "jsxSingleQuote": false,
    "trailingComma": "none",
    "bracketSpacing": true,
    "jsxBracketSameLine": false,
    "arrowParens": "avoid",
    "requirePragma": false,
    "insertPragma": false,
    "proseWrap": "always",
    "htmlWhitespaceSensitivity": "css",
    "endOfLine": "auto",
    "plugins": ["prettier-plugin-apex"],
    "apexInsertFinalNewline": false,
    "overrides": [
        {
            "files": "**/lwc/**/*.html",
            "options": { "parser": "lwc" }
        },
        {
            "files": "**/*.{cmp,page,component}",
            "options": { "parser": "html" }
        }
    ]
}

System Info

System:
    OS: macOS 15.4.1
    CPU: (8) arm64 Apple M1 Pro
    Memory: 2.97 GB / 32.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.15.0 - /usr/local/bin/node
    npm: 11.3.0 - /usr/local/bin/npm
  Languages:
    Bash: 3.2.57 - /bin/bash
    Java: 24.0.1 - /usr/bin/javac
    Perl: 5.34.1 - /usr/bin/perl
    Python3: 3.9.6 - /usr/bin/python3
    Ruby: 2.6.10 - /usr/bin/ruby
  npmPackages:
    @prettier-apex/apex-ast-serializer-darwin-arm64:  2.2.6 
    @prettier/plugin-xml: ^3.4.1 => 3.4.1 
    prettier: ^3.5.3 => 3.5.3 
    prettier-plugin-apex: ^2.2.6 => 2.2.6

[dangmai]

Hi, does this happen to only 1 Apex file, or does this happen to all Apex files?

If it is just 1 file, does it work if you paste the content of the file into https://apex.dangmai.net/ ?

[Sunbvert]

This is happening to me as well today to all my Apex files.
Seems related to an inteiji Idea update I did today. Works in VS Code though.

[maximelets]

This happen to all apex files at the moment

When pasted to https://apex.dangmai.net/ - works fine

[dangmai]

This happen to all apex files at the moment

When pasted to https://apex.dangmai.net/ - works fine

Any chance you just updated IntelliJ as well? I want to figure out whether it's a IntelliJ plugin issue or Prettier Apex issue.

[maximelets]

This happen to all apex files at the moment
When pasted to https://apex.dangmai.net/ - works fine

Any chance you just updated IntelliJ as well? I want to figure out whether it's a IntelliJ plugin issue or Prettier Apex issue.

Yep, that started failing right after update

WebStorm 2025.1.1
Build #WS-251.25410.117, built on May 7, 2025
Source revision: f16670c80a66d

Runtime version: 21.0.6+9-b895.109 aarch64 (JCEF 122.1.9)
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.
Toolkit: sun.lwawt.macosx.LWCToolkit
macOS 15.4.1
GC: G1 Young Generation, G1 Concurrent GC, G1 Old Generation
Memory: 4096M
Cores: 8
Metal Rendering is ON
Registry:
ide.experimental.ui=true
completion.cloud.enableTextCompletion=false
terminal.new.ui=true
Non-Bundled Plugins:
com.jetbrains.space (251.23774.318)
com.intellij.mermaid (0.0.25+IJ.243)
com.intellij.ml.llm (251.23774.42.28.7)
org.jetbrains.plugins.gitlab (251.25410.123-IU)
org.jetbrains.plugins.github (251.25410.123-IU)
com.illuminatedcloud2.intellij (2.3.5.8)

[ASKaranko]

Hello. I have same issue, downgraded Intellij Idea Ulitimate to 2025.1

[dangmai]

Just a quick update - I don't use Jetbrains product anymore, so I don't know if there's a workaround beside downgrading the IDE at the moment.

However I do think I know what the problem is. I'll push an update soon.

[thiakil]

@dangmai any update?

[dangmai]

It's a much harder problem than I anticipated, I'm still working on it. I do have a lot of things IRL that I need to take care of in the near future, hoping to get back to this in about a couple of weeks.

[thiakil]

Any way we can help?

[dangmai]

I always welcome PRs!
With that said, this is probably too big of an issue for someone new to the code base to tackle in a short amount of time. It deals with the way the Apex AST is structured by jorje, compared to the way that Prettier upstream expects it.

My best guest is that Webstorm started using a Prettier API called formatWithCursor in their new version. Prettier Apex has never worked with this API before, because it expects every AST node to have a location attached to it, which is not how jorje structures its AST. So my WIP branch is basically restructuring the AST so that it follows this convention that Prettier upstream expects.

Probably the easiest way to help is to see if there's a configuration in Webstorm that would let users forego this API. Unfortunately I don't have a Webstorm (or an IC2) license to look for that myself. If there's a config for that, it'll be a meaningful workaround while I work on this fairly big change in Prettier Apex itself.

[thiakil]

Sadly not with the built in support - it could conceivably be run as a separate tool tho (much like running it on the command line)

[thiakil]

a quick-fix seems to be just using ?. when grabbing indexes. Not the ideal solution of course, but the code does reformat...

function locStart(node) {
  const location = node.loc ? node.loc : node.location;
  return location?.startIndex;
}
function locEnd(node) {
  const location = node.loc ? node.loc : node.location;
  return location?.endIndex;
}

[dangmai]

a quick-fix seems to be just using ?. when grabbing indexes. Not the ideal solution of course, but the code does reformat...

function locStart(node) {
const location = node.loc ? node.loc : node.location;
return location?.startIndex;
}
function locEnd(node) {
const location = node.loc ? node.loc : node.location;
return location?.endIndex;
}

Yeah that's actually my original plan. The big issue with that is after the command is run, your cursor will be put in the wrong place in the IDE, because Prettier can't actually figure out where to put it - the root AST node doesn't contain the location information, and Prettier would stop going down the tree to find one that does have location info.

[thiakil]

Fair, still better than it not formatting and the git hook yelling at me 😂