infinite formatting loop

[IgorMinar]

given code like this:

class DiffResult {
  toString() {
    return `${pad(this.name, 40)}, ` + `duration: ${pad(this.endTime - this.startTime, 5)}ms, ` + `${pad(this.changedPaths.length + this.removedPaths.length, 5)} changes detected ` +
           `(files: ${pad(this.filesChecked, 5)}, directories: ${pad(this.directoriesChecked, 4)})`;
  }

  log(verbose) {
    let prefixedPaths =
        this.changedPaths.map((p) => `* ${p}`).concat(this.removedPaths.map((p) => `- ${p}`));
    console.log(`Tree diff: ${this}` + ((verbose && prefixedPaths.length) ? ` [\n  ${prefixedPaths.join('\n  ')}\n]` :
                                                                             ''));
  }
}

and running: clang-format -i -style='file' /path/to/test.ts

clang-format reformats the file each execution. this causes our CI to fail even after I reformat the file with clang-format.

[alexeagle]

I had the same problem and spent some time Friday debugging inside stream.equal. Because we are comparing two byte streams, it's pretty hard to improve the error message to show what was expected and what is actual.
I finally found that I could edit the file by hand and get an empty delta - but the output of clang-format -i couldn't produce that for some reason.
The issue seems related to newlines around backtick string literals.

[alexeagle]

I found an easy way to diagnose, just run clang-format with output to stdout and diff against the original.

Here's another repro:

 clang-format /Users/alexeagle/Projects/angular/modules/angular2/src/core/di/binding.ts | diff /Users/alexeagle/Projects/angular/modules/angular2/src/core/di/binding.ts -
402c402
<   toFactory(factoryFunction: Function, dependencies: List<any> = null): Binding {
---
>   toFactory(factoryFunction: Function, dependencies: List<any>= null): Binding {
431c431
<   toAsyncFactory(factoryFunction: Function, dependencies: List< any >= null): Binding {
---
>   toAsyncFactory(factoryFunction: Function, dependencies: List < any >= null): Binding {

[alexeagle]

And here is an explanation of the backtick problem: it wants to join the lines but doesn't know to remove the extra concatenation:

$ clang-format /Users/alexeagle/Projects/angular/modules/angular2/src/core/di/exceptions.ts | diff /Users/alexeagle/Projects/angular/modules/angular2/src/core/di/exceptions.ts -
101,102c101
<       return `Cannot instantiate ${first} synchronously. ` +
<              `It is provided as a promise! ${constructResolvingPath(keys)}`;
---
>       return `Cannot instantiate ${first} synchronously. ` + `It is provided as a promise! ${constructResolvingPath(keys)}`;
150,151c149
<       return `Error during instantiation of ${first}!${constructResolvingPath(keys)}.` +
<              ` ORIGINAL ERROR: ${cause}`;
---
>       return `Error during instantiation of ${first}!${constructResolvingPath(keys)}.` + ` ORIGINAL ERROR: ${cause}`;
185,186c183
<     this.message = `Cannot resolve all parameters for ${stringify(typeOrFunc)}.` +
<                    ` Make sure they all have valid type or annotations.`;
---
>     this.message = `Cannot resolve all parameters for ${stringify(typeOrFunc)}.` + ` Make sure they all have valid type or annotations.`;

[alexeagle]

And now another problem, it can't decide about a line too long vs. everything on one line:

alexeagle-macbookpro2:angular alexeagle$ clang-format /Users/alexeagle/Projects/angular/modules/angular2/src/core/di/exceptions.ts | diff /Users/alexeagle/Projects/angular/modules/angular2/src/core/di/exceptions.ts -
183c183,184
<     this.message = `Cannot resolve all parameters for ${stringify(typeOrFunc)}. Make sure they all have valid type or annotations.`;
---
>     this.message =
>         `Cannot resolve all parameters for ${stringify(typeOrFunc)}. Make sure they all have valid type or annotations.`;
alexeagle-macbookpro2:angular alexeagle$ gulp check-format
Dart SDK detected
[11:33:46] Using gulpfile ~/Projects/angular/gulpfile.js
[11:33:46] Starting 'check-format'...
[11:33:47] WARNING: Files are not properly formatted. Please run
[11:33:47]   clang-format -i -style='file' /Users/alexeagle/Projects/angular/modules/angular2/src/core/di/exceptions.ts
NOTE: this will be promoted to an ERROR in the continuous build
[11:33:47] Finished 'check-format' after 1.21 s
alexeagle-macbookpro2:angular alexeagle$ clang-format /Users/alexeagle/Projects/angular/modules/angular2/src/core/di/exceptions.ts | diff /Users/alexeagle/Projects/angular/modules/angular2/src/core/di/exceptions.ts -
183,184c183
<     this.message =
<         `Cannot resolve all parameters for ${stringify(typeOrFunc)}. Make sure they all have valid type or annotations.`;
---
>     this.message = `Cannot resolve all parameters for ${stringify(typeOrFunc)}. Make sure they all have valid type or annotations.`;

Feels like somewhere backticks need to be treated more like single quotes...

[mprobst]

Repro for the first case:

var a = (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa) || ` [aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa]`;

Clang-Format has a known issue where it miscalculates the width of template string tokens.

Second case (toFactory stuff) is stable after one attempt for me, though the formatting is wrong (whitespace around the < template markers). Will TAL.

[mprobst]

Sent out two fixes:

• http://reviews.llvm.org/D9445 for the template string length calculation if first in line issue
• http://reviews.llvm.org/D9446 for the templated argument default value case

[mprobst]

I think these should be fixed, please reopen if I missed something.