fix(code-server,vscode-web): parse JSONC in extensions.json with sed by rodmk · Pull Request #798 · coder/registry

rodmk · 2026-03-12T15:42:37Z

Fixes #708. Supersedes #707.

Description

auto_install_extensions fails to parse .vscode/extensions.json files containing valid JSONC (block comments, trailing commas). VS Code officially supports these via its built-in JSONC parser with default options.

This PR replaces the existing sed | jq pipeline with a portable two-stage sed | sed | jq pipeline that handles all JSONC features — no new dependencies, no GNU-only extensions.

Type of Change

Bug fix

Module Information

Path: registry/coder/modules/code-server and registry/coder/modules/vscode-web
New version: code-server 1.4.4, vscode-web 1.5.1
Breaking change: No

Problem

The sed 's|//.*||g' | jq pipeline fails on block comments and trailing commas:

registry/registry/coder/modules/code-server/run.sh

Line 133 in f1748c8

    
           extensions=$(sed 's|//.*||g' "$WORKSPACE_DIR"/.vscode/extensions.json | jq -r '.recommendations[]')

registry/registry/coder/modules/vscode-web/run.sh

Line 161 in f1748c8

    
           extensions=$(sed 's|//.*||g' "${WORKSPACE}" | jq -r '(.extensions.recommendations // [])[]')

registry/registry/coder/modules/vscode-web/run.sh

Line 173 in f1748c8

    
           extensions=$(sed 's|//.*||g' "$WORKSPACE_DIR/.vscode/extensions.json" | jq -r '.recommendations[]')

Fix

Extracts a strip_jsonc helper function (defined once per script) that uses a two-stage sed | sed pipeline:

strip_jsonc() {
  sed 's|//.*||g' "$1" | sed -E '
    :a
    N
    $!ba
    s#/[*]([^*]|[*]+[^*/])*[*]+/##g
    s/,[^]}"]*([]}])/\1/g
  '
}

extensions=$(strip_jsonc "$file" | jq -r '(.recommendations // [])[]' 2>/dev/null || true)

Strip line comments (// ...) — a separate line-by-line sed pass where .* naturally stops at the end of each input line
Slurp the file (:a;N;$!ba) — reads the entire file into sed's pattern space for multi-line matching
Strip block comments (/* ... */) — ERE regex handles nested stars, multi-line comments
Strip trailing commas before ] or } — [^]}"]* matches only whitespace/newlines between a trailing comma and its closing bracket

This is safe for extensions.json because extension IDs are restricted to [a-z0-9\-.] by vsce's nameRegex, so comment markers (//, /*) cannot appear inside string values, and the trailing-comma regex [^]}"]* will only ever match whitespace between a comma and its closing bracket. The function is not a general-purpose JSONC parser, but a full parser would be overengineered for this use case.

Cross-platform compatibility

The original sed 's|//.*||g' pipeline only handled line comments. A natural fix would use sed -z to slurp the file for multi-line block comment matching, but -z is a GNU sed extension that does not work on macOS (BSD sed). Since Coder workspaces support macOS (the vscode-web module accepts platform = "darwin"), the fix must be portable.

Line comment stripping is done in a separate first-stage sed (before slurping) because after slurping with :a;N;$!ba, . matches \n in the pattern space, so .* would greedily eat across lines. A single-sed approach using [^\n]* instead of .* works on GNU sed but fails on BSD sed (macOS), where \n inside a bracket expression is interpreted as literal backslash + n per POSIX — causing silent corruption of extension IDs containing the letter n.

This implementation uses only:

sed and sed -E — POSIX-standard flags, supported by both GNU and BSD sed
:a;N;$!ba — standard sed idiom for slurping, works on both platforms
No \+, \s, [^\n], or other GNU-only regex extensions

Alternatives considered

Approach	Tradeoff
`sed -z`	Simpler regex, but `-z` is a GNU sed extension — breaks on macOS BSD sed
*Single `sed -E` with `[^\n]`**	Works on GNU sed, but `\n` in bracket expressions is not portable — BSD sed treats it as literal `\` + `n`, silently corrupting output
`perl -0777 -pe`	Clean one-liner, but no module in the repo uses perl and Apple may remove it from future macOS
Node.js state machine	Correct JSONC parsing, but rejected in #707 as overengineered — 74-line JS file, undocumented bundled node paths, duplicated across modules
Python3	Could parse JSONC natively, but not guaranteed on all workspaces and would need a `command -v` guard
Two-stage `sed \| sed` (this PR)	Extra pipe, but zero new dependencies, fully portable across GNU and BSD sed, minimal diff

Testing & Validation

Tests pass (bun test) — 490 pass, 4 pre-existing failures unrelated to this PR
Code formatted (bun fmt)
Changes tested locally
All 19 JSONC parsing test cases pass
Version bumped via version-bump.sh
Portable across GNU sed (Linux) and BSD sed (macOS)
E2E verified in container: terraform apply with auto_install_extensions = true + JSONC extensions.json (line comments, block comments, trailing commas) correctly extracts and installs all extensions on both ubuntu:22.04 and alpine:latest

Note: E2E was validated locally against code-server only. The same strip_jsonc_for_extensions function is used identically in vscode-web, but vscode-web cannot be E2E tested because use_cached = true (needed to skip the real install) causes the script to exit 0 before reaching the extension installation code path.

Tested the sed+jq pipeline against 19 cases:

Category	Test Cases	Result
Issue #708 reproduction	Block comment + trailing comma (exact issue example)	pass
Strict JSON	No JSONC features	pass
Line comments	End-of-line, standalone line	pass
Block comments	Inline, multi-line, starred, stars inside	pass
Trailing commas	Array, object, same-line, nested	pass
Combined	All JSONC features together	pass
Edge cases	Empty array, missing key, single ext, workspace format, consecutive block comments, empty file	pass

Standalone test script (requires jq)

#!/bin/bash
set -euo pipefail

PASS=0
FAIL=0

strip_jsonc() {
  sed 's|//.*||g' "$1" | sed -E '
    :a
    N
    $!ba
    s#/[*]([^*]|[*]+[^*/])*[*]+/##g
    s/,[^]}"]*([]}])/\1/g
  '
}

run_test() {
  local name="$1" input="$2" jq_expr="$3" expected="$4"
  local tmpfile
  tmpfile=$(mktemp)
  printf '%s' "$input" > "$tmpfile"

  local actual
  actual=$(strip_jsonc "$tmpfile" | jq -r "$jq_expr" 2>/dev/null || true)
  rm -f "$tmpfile"

  if [ "$actual" = "$expected" ]; then
    printf "  ✓ %s\n" "$name"
    PASS=$((PASS + 1))
  else
    printf "  ✗ %s\n" "$name"
    printf "    expected: |%s|\n" "$(echo "$expected" | head -5)"
    printf "    actual:   |%s|\n" "$(echo "$actual" | head -5)"
    FAIL=$((FAIL + 1))
  fi
}

echo "=== Issue #708 reproduction case ==="
run_test "Issue example" '{
  "recommendations": [
    "ms-python.python",
    /* a block comment */
    "dbaeumer.vscode-eslint", // trailing comma
  ]
}' '(.recommendations // [])[]' "ms-python.python
dbaeumer.vscode-eslint"

echo ""
echo "=== Strict JSON (no JSONC features) ==="
run_test "Strict JSON" '{
  "recommendations": [
    "ms-python.python",
    "dbaeumer.vscode-eslint"
  ]
}' '(.recommendations // [])[]' "ms-python.python
dbaeumer.vscode-eslint"

echo ""
echo "=== Line comments ==="
run_test "Line comment at end of line" '{
  "recommendations": [
    "ms-python.python", // python support
    "dbaeumer.vscode-eslint" // linting
  ]
}' '(.recommendations // [])[]' "ms-python.python
dbaeumer.vscode-eslint"

run_test "Line comment on own line" '{
  "recommendations": [
    // this is python
    "ms-python.python",
    "dbaeumer.vscode-eslint"
  ]
}' '(.recommendations // [])[]' "ms-python.python
dbaeumer.vscode-eslint"

echo ""
echo "=== Block comments ==="
run_test "Inline block comment" '{
  "recommendations": [
    "ms-python.python",
    /* eslint */ "dbaeumer.vscode-eslint"
  ]
}' '(.recommendations // [])[]' "ms-python.python
dbaeumer.vscode-eslint"

run_test "Multi-line block comment" '{
  "recommendations": [
    "ms-python.python",
    /*
     * This is a multi-line
     * block comment
     */
    "dbaeumer.vscode-eslint"
  ]
}' '(.recommendations // [])[]' "ms-python.python
dbaeumer.vscode-eslint"

run_test "Block comment with stars /***/" '{
  "recommendations": [
    "ms-python.python",
    /*** starred comment ***/
    "dbaeumer.vscode-eslint"
  ]
}' '(.recommendations // [])[]' "ms-python.python
dbaeumer.vscode-eslint"

run_test "Block comment with * inside" '{
  "recommendations": [
    "ms-python.python",
    /* foo * bar */
    "dbaeumer.vscode-eslint"
  ]
}' '(.recommendations // [])[]' "ms-python.python
dbaeumer.vscode-eslint"

echo ""
echo "=== Trailing commas ==="
run_test "Trailing comma in array" '{
  "recommendations": [
    "ms-python.python",
    "dbaeumer.vscode-eslint",
  ]
}' '(.recommendations // [])[]' "ms-python.python
dbaeumer.vscode-eslint"

run_test "Trailing comma in object" '{
  "recommendations": [
    "ms-python.python",
  ],
}' '(.recommendations // [])[]' "ms-python.python"

run_test "Trailing comma same line as bracket" '{
  "recommendations": ["ms-python.python",]
}' '(.recommendations // [])[]' "ms-python.python"

echo ""
echo "=== Combined JSONC features ==="
run_test "All features combined" '{
  // Top-level comment
  "recommendations": [
    "ms-python.python", // inline comment
    /* block comment */
    "dbaeumer.vscode-eslint",
    /*
     * Multi-line
     */
    "esbenp.prettier-vscode", // trailing comma below
  ],
}' '(.recommendations // [])[]' "ms-python.python
dbaeumer.vscode-eslint
esbenp.prettier-vscode"

echo ""
echo "=== Edge cases ==="
run_test "Empty recommendations" '{
  "recommendations": []
}' '(.recommendations // [])[]' ""

run_test "Missing recommendations key" '{
  "unwanted": ["foo"]
}' '(.recommendations // [])[]' ""

run_test "Single extension" '{
  "recommendations": ["ms-python.python"]
}' '(.recommendations // [])[]' "ms-python.python"

run_test "Workspace file format (.extensions.recommendations)" '{
  "extensions": {
    "recommendations": [
      "ms-python.python",
      "dbaeumer.vscode-eslint"
    ]
  }
}' '(.extensions.recommendations // [])[]' "ms-python.python
dbaeumer.vscode-eslint"

run_test "Workspace file with JSONC" '{
  "extensions": {
    // Recommended extensions
    "recommendations": [
      "ms-python.python",
      /* linting */ "dbaeumer.vscode-eslint", // trailing comma
    ],
  },
}' '(.extensions.recommendations // [])[]' "ms-python.python
dbaeumer.vscode-eslint"

run_test "Consecutive block comments" '{
  "recommendations": [
    /* first */ /* second */
    "ms-python.python"
  ]
}' '(.recommendations // [])[]' "ms-python.python"

run_test "Empty file" '' '(.recommendations // [])[]' ""

echo ""
echo "=== Results ==="
echo "Passed: $PASS"
echo "Failed: $FAIL"
[ "$FAIL" -eq 0 ] && echo "All tests passed!" || exit 1

Related Issues

Generated with Claude Code using Claude Opus 4.6

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Copilot

Pull request overview

This PR improves auto-installation of VS Code/code-server extensions by attempting to preprocess JSONC workspace/extension files (comments + trailing commas) before feeding them to jq, and updates the module README version pins accordingly.

Changes:

Add a strip_jsonc_for_extensions() helper in both vscode-web and code-server modules, then use it when extracting extension recommendations via jq.
Make jq parsing tolerant of missing recommendations arrays by defaulting to [].
Bump module versions referenced in READMEs and add a typos dictionary entry to avoid false positives.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
registry/coder/modules/vscode-web/run.sh	Adds JSONC preprocessing helper and uses it for workspace/extensions parsing before `jq`.
registry/coder/modules/vscode-web/README.md	Updates example module version pins to 1.5.1.
registry/coder/modules/code-server/run.sh	Adds JSONC preprocessing helper and uses it for `.vscode/extensions.json` parsing before `jq`.
registry/coder/modules/code-server/README.md	Updates example module version pins to 1.4.4.
.github/typos.toml	Adds `ba` to the allowed word list (sed label pattern).

DevelopmentCats

I agree with you that the Copilot Comments were wrong.

This LGTM though thanks for the fix and quick response!! 😸

35C4n0r · 2026-07-06T09:27:08Z

@rodmk can you resolve the conflicts.

rodmk · 2026-07-07T14:55:15Z

@35C4n0r Whoa, I didn't realize this hadn't been merged yet, it was approved months ago 😅 I'll resolve the conflicts promptly.

# Conflicts: # registry/coder/modules/code-server/README.md # registry/coder/modules/code-server/run.sh # registry/coder/modules/vscode-web/README.md

rodmk · 2026-07-07T15:18:02Z

Resolved the conflicts against the latest main. The only real overlap was in the code-server/vscode-web run.sh scripts: I merged the new WORKSPACE-file support together with this PR's JSONC parsing, so both commented extensions.json files and .code-workspace files work. Version bumps re-based onto the current releases — code-server → 1.5.1, vscode-web → 1.6.1.

Validation: fmt, README validation, golangci-lint, and the full code-server + vscode-web test suites all pass. (The one failing test is an unrelated nexus-repository timeout flake.)

🤖 Generated with Claude Code using Claude Opus 4.8

35C4n0r

Two P1 bugs found in the strip_jsonc_for_extensions shell function introduced by this PR. Both are verified with live tests. Each inline comment above includes a suggested fix or a plain diff.

Summary of required changes:

#	File	Issue	Severity
1	`code-server/run.sh` lines 119–128	Line-comment pass runs before block-comment slurp — corrupts URLs in comments and settings; single-line files pass through unprocessed	P1
2	`vscode-web/run.sh` lines 153–162	Same stage-ordering bug	P1
3	`code-server/run.sh` line 137	`RECOMMENDATIONS_QUERY` not null-safe (vscode-web was fixed, code-server was not)	P1

Generated by Coder Agents on behalf of @35C4n0r.

35C4n0r · 2026-07-07T17:15:46Z

+# Strip JSONC features (block/line comments, trailing commas) for jq parsing
+strip_jsonc_for_extensions() {
+  sed 's|//.*||g' "$1" | sed -E '
+    :a
+    N
+    $!ba
+    s#/[*]([^*]|[*]+[^*/])*[*]+/##g
+    s/,[^]}"]*([]}])/\1/g
+  '
+}


P1 — sed 's|//.*||g' runs before block-comment removal; two silent failures result.

Inline block comment containing :// — a line like /* https://open-vsx.org */ has //open-vsx.org */ stripped by stage 1, leaving /* https: in the buffer. Stage 2 finds no closing */ and passes the fragment through. jq then fails with parse error: Invalid numeric literal — zero extensions installed, nothing printed to the user. Verified locally.

URL-valued settings in .code-workspace files — "http.proxy": "https://proxy.corp:8080" becomes "http.proxy": "https: (unclosed string literal). jq exits with Invalid string: control characters from U+0000 through U+001F must be escaped. Same silent failure. Verified locally.

The suggestion merges into a single sed -E pass with block comments removed first. s#//[^\n]*##g then handles line comments on the slurped buffer — [^\n]* stops at each embedded newline, so it is equivalent to per-line stripping without a separate process. This fixes failure #1. Failure #2 (URL string values) is a fundamental limit of the regex approach — only a JSONC-aware parser can reliably distinguish // inside a string from // in a comment.

Suggested change

# Strip JSONC features (block/line comments, trailing commas) for jq parsing

strip_jsonc_for_extensions() {

sed 's|//.*||g' "$1" | sed -E '

:a

N

$!ba

s#/[*]([^*]|[*]+[^*/])*[*]+/##g

s/,[^]}"]*([]}])/\1/g

'

}

# Strip JSONC features (block/line comments, trailing commas) for jq parsing

strip_jsonc_for_extensions() {

sed -E '

:a

N

$!ba

s#/[*]([^*]|[*]+[^*/])*[*]+/##g

s#//[^\n]*##g

s/,[^]}"]*([]}])/\1/g

' "$1"

}

Generated by Coder Agents on behalf of @35C4n0r.

35C4n0r · 2026-07-07T17:16:47Z

+# Strip JSONC features (block/line comments, trailing commas) for jq parsing
+strip_jsonc_for_extensions() {
+  sed 's|//.*||g' "$1" | sed -E '
+    :a
+    N
+    $!ba
+    s#/[*]([^*]|[*]+[^*/])*[*]+/##g
+    s/,[^]}"]*([]}])/\1/g
+  '
+}


P1 — URL corruption / single-line file: stage ordering is wrong

The current implementation pipes through a line-comment stripper before slurping into a multi-line buffer:

sed 's|//.*||g' "$1" | sed -E ' :a N $!ba s#/[*]([^*]|[*]+[^*/])*[*]+/##g ...

Two verified failure modes:

URL inside a block comment — /* https://open-vsx.org */: stage 1 strips ://open-vsx.org */, leaving /* https: unclosed. Stage 2's block-comment regex can't match, jq receives garbage and exits non-zero — zero extensions installed, no error surfaced.

URL-valued setting — "http.proxy": "https://proxy.corp": stage 1 strips ://proxy.corp", producing an unclosed string literal. jq exits 5, zero extensions installed silently.

Single-line input — :a;N;$!ba exits immediately at EOF without running any substitution (GNU sed behaviour on last-line N). A one-line {"recommendations":["ext1",]} is passed through unchanged and jq fails on the trailing comma.

Fix: slurp the whole file first, then strip block comments, then line comments — in a single sed invocation:

Suggested change

# Strip JSONC features (block/line comments, trailing commas) for jq parsing

strip_jsonc_for_extensions() {

sed 's|//.*||g' "$1" | sed -E '

:a

N

$!ba

s#/[*]([^*]|[*]+[^*/])*[*]+/##g

s/,[^]}"]*([]}])/\1/g

'

}

strip_jsonc_for_extensions() {

sed -E '

:a

N

$!ba

s#/[*]([^*]|[*]+[^*/])*[*]+/##g

s#//[^\n]*##g

s/,[^]}"]*([]}])/\1/g

' "$1"

}

s#//[^\n]*##g is safe on the slurped buffer because [^\n]* stops at each embedded newline, so it only strips to end-of-line.

Generated by Coder Agents on behalf of @35C4n0r.

35C4n0r · 2026-07-07T17:17:08Z

-    # Use sed to remove single-line comments before parsing with jq
-    extensions=$(sed 's|//.*||g' "$RECOMMENDATIONS_FILE" | jq -r "$RECOMMENDATIONS_QUERY")
+    # Strip JSONC comments and trailing commas before parsing with jq
+    extensions=$(strip_jsonc_for_extensions "$RECOMMENDATIONS_FILE" | jq -r "$RECOMMENDATIONS_QUERY")


P1 — code-server null-safety gap in RECOMMENDATIONS_QUERY

This PR upgrades vscode-web to use a null-safe query:

# vscode-web/run.sh (this PR) RECOMMENDATIONS_QUERY='(.recommendations // [])[]'

but code-server was not updated in parallel. The query at line 137 of code-server/run.sh is still:

RECOMMENDATIONS_QUERY=".recommendations[]"

A valid extensions.json with no recommendations key at all (permitted by the VS Code schema) causes jq to emit null | .[] which exits non-zero — silently discarding all extension installations on code-server while vscode-web handles the same file cleanly.

Fix (line 137, not in the diff hunk above — apply manually):

- RECOMMENDATIONS_QUERY=".recommendations[]" + RECOMMENDATIONS_QUERY='(.recommendations // [])[]'

Note the single-quote change: the expression contains no shell variables, so single quotes are correct and prevent accidental expansion.

Generated by Coder Agents on behalf of @35C4n0r.

fix(code-server,vscode-web): parse JSONC in extensions.json with sed

a231800

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

rodmk requested a review from jdomeracki-coder as a code owner March 12, 2026 15:42

DevelopmentCats requested a review from Copilot March 12, 2026 19:46

Copilot started reviewing on behalf of DevelopmentCats March 12, 2026 19:46 View session

Copilot AI reviewed Mar 12, 2026

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Comment thread registry/coder/modules/vscode-web/run.sh

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Comment thread registry/coder/modules/code-server/run.sh

DevelopmentCats approved these changes Mar 13, 2026

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Merge branch 'main' into fix/jsonc-parsing-708

8b234ee

Merge remote-tracking branch 'upstream/main' into fix/jsonc-parsing-708

1b9f597

# Conflicts: # registry/coder/modules/code-server/README.md # registry/coder/modules/code-server/run.sh # registry/coder/modules/vscode-web/README.md

35C4n0r requested review from 35C4n0r and removed request for jdomeracki-coder July 7, 2026 16:18

35C4n0r requested changes Jul 7, 2026

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fix(code-server,vscode-web): parse JSONC in extensions.json with sed#798

fix(code-server,vscode-web): parse JSONC in extensions.json with sed#798
rodmk wants to merge 3 commits into
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rodmk:fix/jsonc-parsing-708

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rodmk commented Mar 12, 2026

Description

Type of Change

Module Information

Problem

Fix

Cross-platform compatibility

Alternatives considered

Testing & Validation

Related Issues

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