Hint the user about why compilation fails

[machour]

Migrating from react-native-i18n to lingui, I needed to automate the catalog conversion a bit.

At some point, I messed up a string in a message.json file, and struggled a bit to find the culprit:

$ lingui compile
Compiling message catalogs…

/Users/didou/js/react-native/git-point/node_modules/messageformat-parser/parser.js:1975
    throw peg$buildStructuredError(
    ^
SyntaxError: Expected [\t-\r \x85‎‏

] or [^\t-\r \x85‎‏

!-/:-@[-\^`{-~¡-§©«¬®°±¶»¿×÷‐-‧‰-‾⁁-⁓⁕-⁞←-⑟─-❵➔-⯿⸀-⹿、-〃〈-〠〰﴾﴿﹅﹆] but "{" found.
    at peg$buildStructuredError (/Users/didou/js/react-native/git-point/node_modules/messageformat-parser/parser.js:392:12)
    at peg$parse (/Users/didou/js/react-native/git-point/node_modules/messageformat-parser/parser.js:1975:11)
    at compile (/Users/didou/js/react-native/git-point/node_modules/@lingui/cli/api/compile.js:74:47)
    at /Users/didou/js/react-native/git-point/node_modules/@lingui/cli/api/compile.js:89:51
    at Array.map (<anonymous>)
    at createCompiledCatalog (/Users/didou/js/react-native/git-point/node_modules/@lingui/cli/api/compile.js:87:56)
    at /Users/didou/js/react-native/git-point/node_modules/@lingui/cli/lingui-compile.js:85:62
    at Array.map (<anonymous>)
    at command (/Users/didou/js/react-native/git-point/node_modules/@lingui/cli/lingui-compile.js:45:18)
    at Object.<anonymous> (/Users/didou/js/react-native/git-point/node_modules/@lingui/cli/lingui-compile.js:109:17)
error An unexpected error occurred: "Command failed.

I managed to find the issue by tracing in lingui-compile:

  "{0} files": {
    "translation": "{{numFiles}} dosieroj",   // <---- {{numFiles}} should be {0} instead
    "origin": [["src/repository/screens/pull-diff.screen.js", 98]]
  },

catching errors from messageformat-parser and outputting something like Error: Invalid string found in locale/eo/messages.json for message "{0} files" would be helpful.

[tricoder42]

Fixed in latest release v2.3.0.