fix(code-placeholders): harden shell placeholder interpolation in arithmetic contexts

Author: waleedlatif1

apps/sim/lib/execution/code-placeholders/compiler.test.ts

@@ -1053,6 +1053,37 @@ describe('code placeholder compiler', () => {
     'total=$(( $(( 1 + 1 )) + {{KEY}} ))',
     'cat <<PAYLOAD\n$(( {{KEY}} * 2 ))\nPAYLOAD',
     'cat <<PAYLOAD\n$[ {{KEY}} * 2 ]\nPAYLOAD',
+    'echo $(( $(cat <<EOF\n{{KEY}}\nEOF\n) + 1 ))',
+    "echo $(( $(cat <<'EOF'\n{{KEY}}\nEOF\n) + 1 ))",
+    "echo $(( $(cat <<-'EOF'\n\t{{KEY}}\n\tEOF\n) + 1 ))",
+    '[[ {{KEY}} -eq 0 ]] && echo zero',
+    '[[ "{{KEY}}" -eq 0 ]] && echo zero',
+    'if [[ 0 -lt {{KEY}} ]]; then echo positive; fi',
+    '[[ -n x && ( "{{KEY}}" -ge 1 ) ]]',
+    '[[ $(printf "%s" "{{KEY}}") -ne 0 ]]',
+    '[[ $(printf "%s" "{{KEY}}"; echo 1) -le 0 ]]',
+    '[[ $(cat <<EOF\n{{KEY}}\nEOF\n) -gt 0 ]]',
+    'let "x={{KEY}}"',
+    'let x={{KEY}}+1',
+    'declare -i x="{{KEY}}"',
+    'typeset -i x={{KEY}}',
+    'f() { local -i x="{{KEY}}"; }',
+    'declare -ai values=("{{KEY}}")',
+    'declare -x -i x="{{KEY}}"',
+    // biome-ignore lint/suspicious/noTemplateCurlyInString: shell parameter expansion, not a JS template
+    'a=(1 2); echo "${a[{{KEY}}]}"',
+    // biome-ignore lint/suspicious/noTemplateCurlyInString: shell parameter expansion, not a JS template
+    's=abc; echo "${s:{{KEY}}}"',
+    // biome-ignore lint/suspicious/noTemplateCurlyInString: shell parameter expansion, not a JS template
+    's=abc; echo "${s:0:{{KEY}}}"',
+    // biome-ignore lint/suspicious/noTemplateCurlyInString: shell parameter expansion, not a JS template
+    's=abc; echo "${s: -1:{{KEY}}}"',
+    // biome-ignore lint/suspicious/noTemplateCurlyInString: shell parameter expansion, not a JS template
+    'set -- a b; echo "${@:{{KEY}}}"',
+    // biome-ignore lint/suspicious/noTemplateCurlyInString: shell parameter expansion, not a JS template
+    'cat <<PAYLOAD\n${a[{{KEY}}]}\nPAYLOAD',
+    // biome-ignore lint/suspicious/noTemplateCurlyInString: shell parameter expansion, not a JS template
+    'cat <<PAYLOAD\n${s:{{KEY}}}\nPAYLOAD',
   ])('rejects shell placeholders whose values enter arithmetic: %s', async (code) => {
     await expect(
       compileCodePlaceholders({
@@ -1087,6 +1118,41 @@ describe('code placeholder compiler', () => {
     )
   })
 
+  it('compiles shell placeholders beside arithmetic that never evaluates them', async () => {
+    const value = 'values[$(printf injected >&2)]'
+    const compiled = await compileCodePlaceholders({
+      code: [
+        '[ "{{KEY}}" -eq 0 ] 2>/dev/null || printf "%s\\n" not-zero',
+        '[[ "{{KEY}}" == values* && 1 -eq 1 ]] && printf "%s\\n" matched',
+        'let total=1+1; printf "%s\\n" "{{KEY}}"',
+        'f() { local copy="{{KEY}}"; printf "%s\\n" "$copy"; }; f',
+        'declare copy="{{KEY}}"; printf "%s\\n" "$copy"',
+        // biome-ignore lint/suspicious/noTemplateCurlyInString: shell parameter expansion, not a JS template
+        'printf "%s\\n" "${missing:-{{KEY}}}"',
+        // biome-ignore lint/suspicious/noTemplateCurlyInString: shell parameter expansion, not a JS template
+        'a=(x y); printf "%s\\n" "${a[1]}{{KEY}}"',
+        'printf "%s\\n" "let {{KEY}}"',
+        'printf "%s\\n" "items[{{KEY}}]"',
+        '# declare -i n',
+        'n="{{KEY}}"; printf "%s\\n" "$n"',
+        'let total=1 <<EOF',
+        '{{KEY}}',
+        'EOF',
+        'printf "%s\\n" "$total"',
+        'cat <<PAYLOAD',
+        '{{KEY}} $(( 1 + 1 ))',
+        'PAYLOAD',
+      ].join('\n'),
+      language: CodeLanguage.Shell,
+      environmentVariables: { KEY: value },
+    })
+
+    expect(executeShell(`{\n${compiled.code}\n} 2>&1`, compiled.bindings)).toBe(
+      `not-zero\nmatched\n${value}\n${value}\n${value}\n${value}\ny${value}\n` +
+        `let ${value}\nitems[${value}]\n${value}\n1\n${value} 2\n`
+    )
+  })
+
   it('discovers shell arithmetic placeholders without compiling missing values', async () => {
     const code = 'total=$(( {{MISSING}} + {{KEY}} ))'
     await expect(analyzeCodePlaceholders(code, CodeLanguage.Shell)).resolves.toEqual([

apps/sim/lib/execution/code-placeholders/shared.ts

@@ -327,12 +327,12 @@ export function createOffsetRangeLookup(
  * The placeholders lying wholly inside `[start, end]`. Occurrences are ordered and never
  * overlap, so the matches are one contiguous run found by bisection.
  */
-export function occurrencesWithin(
-  occurrences: readonly CodePlaceholderOccurrence[],
+export function occurrencesWithin<T extends Pick<CodePlaceholderOccurrence, 'start' | 'end'>>(
+  occurrences: readonly T[],
   start: number,
   end: number
-): CodePlaceholderOccurrence[] {
-  const matches: CodePlaceholderOccurrence[] = []
+): T[] {
+  const matches: T[] = []
   for (
     let index = partitionPoint(occurrences, (occurrence) => occurrence.start < start);
     index < occurrences.length && occurrences[index].end <= end;