MergeStrategy seems to be completely broken (mergeWith failure)

[mina-skunk]

Re-post of angular/devkit#745

Bug Report or Feature Request (mark with an x)

- [x] bug report -> please search issues before submitting
- [ ] feature request

Area

- [ ] devkit
- [x] schematics

Versions

Node v8.11.1
NPM 5.8.0
Mac OS High Sierra

Repro steps

Use the following schematic

import { Rule, url, apply, mergeWith, chain, MergeStrategy } from '@angular-devkit/schematics';

export function index(): Rule {
  return chain([
    simpleMerge(),
  ]);
}

function simpleMerge(): Rule {

  const source = url('./files');

  return mergeWith(source, MergeStrategy.Overwrite);
}

The log given by the failure

schematics .:boilerplate

ERROR! /src/app/app.component.html already exists.
ERROR! /src/app/app.component.spec.ts already exists.
ERROR! /src/app/app.component.ts already exists.
ERROR! /src/app/app.module.ts already exists.
ERROR! /src/assets/.gitkeep already exists.
ERROR! /src/environments/environment.prod.ts already exists.
ERROR! /src/environments/environment.ts already exists.
ERROR! /src/index.html already exists.

Desired functionality

All files should be overwritten.

Mention any other details that might be useful

I tried every MergeStrategy possible (AllowOverwriteConflict, etc.), same result.

angular/devkit#745
https://stackoverflow.com/questions/48957132/how-to-overwrite-file-with-angular-schematics

[clydin]

Could you provide the versions used?

I cannot answer with certainty without knowing the versions but this PR (#11274) will most likely correct the behavior.

[mina-skunk]

version 0.6.8

dup repo https://github.com/gatimus/schematics-merge-strategy

[hansl]

Could you try with the RC of 0.7? I fixed a lot of issues by reworking the whole Tree implementation, should have fixed a few of those merging issues (amongst others, e.g. branching).

[hansl]

Dupe of #11246. Let's keep this one for tracking though as it has more information.

[mina-skunk]

Still duplicating on 0.7.0-rc.3 https://github.com/gatimus/schematics-merge-strategy/tree/RC-0.7

[cgatian]

This is making me cry 😢

[joeson1]

Is this already fixed?
I have following workaround:

const templateSource = apply(url('./project-files'), [
      template({ ...strings, ...options }),
      move(options.path),
      forEach((fileEntry: FileEntry) => {
        if (host.exists(fileEntry.path)) {
          host.overwrite(fileEntry.path, fileEntry.content);
        }
        return fileEntry;
      }),
    ]);

[tinesoft]

Hi,

For me, the issue appears after upgrading my schematics "dependencies" from:

 {
    "@angular-devkit/core": "^0.6.8",
    "@angular-devkit/schematics": "^0.6.8",
    "typescript": "^2.5.1"
  },

to:

 {
    "@angular-devkit/core": "^0.7.3",
    "@angular-devkit/schematics": "^0.7.3",
    "typescript": "^2.9.0"
  },

Version v0.6.8's mergeWith was working fine...

@joeson1 : i tried your workaround, but it didn't help 😞 ...

[mina-skunk]

@joeson1 where do you assign host?

[mina-skunk]

@tinesoft I get the exact same behavior with v0.6.8 as with v0.7.3

[Bored-Bohr]

I believe this is the same issue as #12088.

I originally commented this on #12088:
This issue still exists in 0.8.4.

The issue occurs on HostTree merge. I've detailed the simplified propagation below:

1. The url function generates actions with kind 'c'
2. Since there exists no prior actions this._willCreate(path) || this._willOverwrite(path) returns false.
3. this._record.create triggers.
4. This throws the fileDoesNotExistException on execute.