| 1 | /** |
| 2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
| 3 | * |
| 4 | * This source code is licensed under the MIT license found in the |
| 5 | * LICENSE file in the root directory of this source tree. |
| 6 | */ |
| 7 | |
| 8 | import type * as BabelCore from '@babel/core'; |
| 9 | import {hasReactLikeFunctions} from './prefilter'; |
| 10 | import {compileWithRust, type BindingRenameInfo} from './bridge'; |
| 11 | import {extractScopeInfo} from './scope'; |
| 12 | import {resolveOptions, type PluginOptions} from './options'; |
| 13 | |
| 14 | export default function BabelPluginReactCompilerRust( |
| 15 | _babel: typeof BabelCore, |
| 16 | ): BabelCore.PluginObj { |
| 17 | let compiledProgram = false; |
| 18 | return { |
| 19 | name: 'react-compiler-rust', |
| 20 | visitor: { |
| 21 | Program: { |
| 22 | enter(prog, pass): void { |
| 23 | // Guard against re-entry: replaceWith() below causes Babel |
| 24 | // to re-traverse the new Program, which would re-trigger this |
| 25 | // handler. Skip if we've already compiled. |
| 26 | if (compiledProgram) { |
| 27 | return; |
| 28 | } |
| 29 | compiledProgram = true; |
| 30 | const filename = pass.filename ?? null; |
| 31 | |
| 32 | // Step 1: Resolve options (pre-resolve JS-only values) |
| 33 | const opts = resolveOptions( |
| 34 | pass.opts as PluginOptions, |
| 35 | pass.file, |
| 36 | filename, |
| 37 | pass.file.ast, |
| 38 | ); |
| 39 | |
| 40 | // Step 2: Quick bail — should we compile this file at all? |
| 41 | if (!opts.shouldCompile) { |
| 42 | return; |
| 43 | } |
| 44 | |
| 45 | // Step 3: Pre-filter — any potential React functions? |
| 46 | // Skip prefilter when compilationMode is 'all' (compiles all functions) |
| 47 | if (opts.compilationMode !== 'all' && !hasReactLikeFunctions(prog)) { |
| 48 | return; |
| 49 | } |
| 50 | |
| 51 | // Step 4: Extract scope info |
| 52 | const logger = (pass.opts as PluginOptions).logger; |
| 53 | let scopeInfo; |
| 54 | try { |
| 55 | scopeInfo = extractScopeInfo(prog); |
| 56 | } catch (e) { |
| 57 | // Scope extraction can fail on unsupported syntax (e.g., reserved |
| 58 | // word as binding name). Report as CompileUnexpectedThrow + |
| 59 | // CompileError, matching TS compiler behavior. |
| 60 | const errMsg = e instanceof Error ? e.message : String(e); |
| 61 | const dotIdx = errMsg.indexOf('. '); |
| 62 | const reason = dotIdx >= 0 ? errMsg.substring(0, dotIdx) : errMsg; |
| 63 | let description: string | undefined = |
| 64 | dotIdx >= 0 ? errMsg.substring(dotIdx + 2) : undefined; |
| 65 | if (description?.endsWith('.')) { |
| 66 | description = description.slice(0, -1); |
| 67 | } |
| 68 | if (logger) { |
| 69 | logger.logEvent(filename, { |
| 70 | kind: 'CompileUnexpectedThrow', |
| 71 | data: `Error: ${errMsg}`, |
| 72 | }); |
| 73 | logger.logEvent(filename, { |
| 74 | kind: 'CompileError', |
| 75 | detail: { |
| 76 | reason, |
| 77 | severity: 'Error', |
| 78 | category: 'Syntax', |
| 79 | description: description ?? null, |
| 80 | suggestions: null, |
| 81 | details: [ |
| 82 | { |
| 83 | kind: 'error', |
| 84 | loc: null, |
| 85 | message: 'reserved word', |
| 86 | }, |
| 87 | ], |
| 88 | }, |
| 89 | }); |
| 90 | } |
| 91 | const panicThreshold = (pass.opts as PluginOptions).panicThreshold; |
| 92 | if ( |
| 93 | panicThreshold === 'all_errors' || |
| 94 | panicThreshold === 'critical_errors' |
| 95 | ) { |
| 96 | const heading = 'Error'; |
| 97 | const parts = [`${heading}: ${reason}`]; |
| 98 | if (description != null) { |
| 99 | parts.push(`\n\n${description}.`); |
| 100 | } |
| 101 | const formatted = `Found 1 error:\n\n${parts.join('')}`; |
| 102 | const err = new Error(formatted); |
| 103 | (err as any).details = []; |
| 104 | throw err; |
| 105 | } |
| 106 | return; |
| 107 | } |
| 108 | |
| 109 | // Step 5: Call Rust compiler |
| 110 | const optsForRust = |
| 111 | (logger as any)?.debugLogIRs != null |
| 112 | ? {...opts, __debug: true} |
| 113 | : opts; |
| 114 | const result = compileWithRust( |
| 115 | pass.file.ast, |
| 116 | scopeInfo, |
| 117 | optsForRust, |
| 118 | pass.file.code ?? null, |
| 119 | ); |
| 120 | |
| 121 | // Step 6: Forward logger events and debug logs via orderedLog |
| 122 | if (logger && result.orderedLog && result.orderedLog.length > 0) { |
| 123 | for (const item of result.orderedLog) { |
| 124 | if (item.type === 'event') { |
| 125 | logger.logEvent(filename, item.event); |
| 126 | } else if (item.type === 'debug' && logger.debugLogIRs) { |
| 127 | logger.debugLogIRs(item.entry); |
| 128 | } |
| 129 | } |
| 130 | } else if (logger && result.events) { |
| 131 | for (const event of result.events) { |
| 132 | logger.logEvent(filename, event); |
| 133 | } |
| 134 | } |
| 135 | |
| 136 | // Step 7: Handle result |
| 137 | if (result.kind === 'error') { |
| 138 | const message = |
| 139 | (result.error as any).rawMessage ?? |
| 140 | (result.error as any).formattedMessage ?? |
| 141 | 'Unexpected compiler error'; |
| 142 | const err = new Error(message); |
| 143 | (err as any).details = result.error.details; |
| 144 | throw err; |
| 145 | } |
| 146 | |
| 147 | if (result.ast != null) { |
| 148 | // Replace the program with Rust's compiled output. |
| 149 | const newFile = result.ast as any; |
| 150 | const newProgram = newFile.program ?? newFile; |
| 151 | |
| 152 | // After JSON round-tripping through Rust, comment objects that were |
| 153 | // shared by reference in Babel's AST (e.g., a comment between two |
| 154 | // statements appears as trailingComments on stmt A and leadingComments |
| 155 | // on stmt B, sharing the same JS object) become separate objects. |
| 156 | // Babel's generator uses reference identity to avoid printing the |
| 157 | // same comment twice. We restore sharing by deduplicating: for each |
| 158 | // unique comment position, we keep one canonical object and replace |
| 159 | // all duplicates with references to it. |
| 160 | deduplicateComments(newProgram); |
| 161 | |
| 162 | // Use Babel's replaceWith() API so that subsequent plugins |
| 163 | // (babel-plugin-fbt, babel-plugin-fbt-runtime, babel-plugin-idx) |
| 164 | // properly traverse the new AST. Direct assignment to |
| 165 | // pass.file.ast.program bypasses Babel's traversal tracking, |
| 166 | // and prog.skip() would prevent all merged plugin visitors from |
| 167 | // running on the new children. |
| 168 | pass.file.ast.comments = []; |
| 169 | prog.replaceWith(newProgram); |
| 170 | } |
| 171 | |
| 172 | // Apply variable renames from lowering to the Babel AST. |
| 173 | // Must run AFTER the AST replacement so that scope.rename() |
| 174 | // operates on the compiled output, not the original (discarded) AST. |
| 175 | if (result.renames != null && result.renames.length > 0) { |
| 176 | applyRenames(prog, result.renames); |
| 177 | } |
| 178 | }, |
| 179 | }, |
| 180 | }, |
| 181 | }; |
| 182 | } |
| 183 | |
| 184 | /** |
| 185 | * Deduplicate comments across AST nodes after JSON round-tripping. |
| 186 | * |
| 187 | * Babel's parser attaches the same comment object to multiple nodes |
| 188 | * (e.g., as trailingComments on node A and leadingComments on node B). |
| 189 | * The code generator uses reference identity (`===`) to avoid printing |
| 190 | * a comment twice. After JSON serialization/deserialization through Rust, |
| 191 | * these shared references become separate objects with identical content. |
| 192 | * |
| 193 | * This function walks the AST, finds comments with the same (start, end) |
| 194 | * position, and replaces duplicates with references to a single canonical |
| 195 | * object, restoring the sharing that Babel expects. |
| 196 | */ |
| 197 | /** |
| 198 | * Apply variable renames from the Rust compiler's lowering phase to the Babel AST. |
| 199 | * |
| 200 | * During lowering, the Rust compiler renames variables that shadow outer bindings |
| 201 | * (e.g., an inner function parameter `ref` that shadows an outer `ref` becomes `ref_0`). |
| 202 | * In the TS compiler, this is done via Babel's `scope.rename()` during HIRBuilder. |
| 203 | * Since the Rust compiler doesn't have access to Babel's scope API, it records the |
| 204 | * renames and returns them here for the Babel plugin to apply. |
| 205 | */ |
| 206 | function applyRenames( |
| 207 | prog: BabelCore.NodePath<BabelCore.types.Program>, |
| 208 | renames: Array<BindingRenameInfo>, |
| 209 | ): void { |
| 210 | // Build a map from declaration start position to rename info |
| 211 | const renamesByPos = new Map<number, BindingRenameInfo>(); |
| 212 | for (const rename of renames) { |
| 213 | renamesByPos.set(rename.declarationStart, rename); |
| 214 | } |
| 215 | |
| 216 | // Traverse all scopes to find bindings that match by position |
| 217 | prog.traverse({ |
| 218 | Scope(path: BabelCore.NodePath) { |
| 219 | const scope = path.scope; |
| 220 | for (const [name, binding] of Object.entries( |
| 221 | scope.bindings as Record<string, any>, |
| 222 | )) { |
| 223 | const start = binding.identifier.start; |
| 224 | if (start != null) { |
| 225 | const rename = renamesByPos.get(start); |
| 226 | if (rename != null && name === rename.original) { |
| 227 | scope.rename(rename.original, rename.renamed); |
| 228 | renamesByPos.delete(start); |
| 229 | } |
| 230 | } |
| 231 | } |
| 232 | }, |
| 233 | } as BabelCore.Visitor); |
| 234 | } |
| 235 | |
| 236 | function deduplicateComments(node: any): void { |
| 237 | // Map from "start:end" to canonical comment object |
| 238 | const canonical = new Map<string, any>(); |
| 239 | |
| 240 | function dedup(comments: any[]): any[] { |
| 241 | return comments.map(c => { |
| 242 | const key = `${c.start}:${c.end}`; |
| 243 | const existing = canonical.get(key); |
| 244 | if (existing != null) { |
| 245 | return existing; |
| 246 | } |
| 247 | canonical.set(key, c); |
| 248 | return c; |
| 249 | }); |
| 250 | } |
| 251 | |
| 252 | function visit(n: any): void { |
| 253 | if (n == null || typeof n !== 'object') return; |
| 254 | if (Array.isArray(n)) { |
| 255 | for (const item of n) { |
| 256 | visit(item); |
| 257 | } |
| 258 | return; |
| 259 | } |
| 260 | if (n.leadingComments) { |
| 261 | n.leadingComments = dedup(n.leadingComments); |
| 262 | } |
| 263 | if (n.trailingComments) { |
| 264 | n.trailingComments = dedup(n.trailingComments); |
| 265 | } |
| 266 | if (n.innerComments) { |
| 267 | n.innerComments = dedup(n.innerComments); |
| 268 | } |
| 269 | for (const key of Object.keys(n)) { |
| 270 | if ( |
| 271 | key === 'leadingComments' || |
| 272 | key === 'trailingComments' || |
| 273 | key === 'innerComments' || |
| 274 | key === 'start' || |
| 275 | key === 'end' || |
| 276 | key === 'loc' |
| 277 | ) { |
| 278 | continue; |
| 279 | } |
| 280 | visit(n[key]); |
| 281 | } |
| 282 | } |
| 283 | |
| 284 | visit(node); |
| 285 | } |