📎 Implement `biome lint --summary`

[Conaclos]

Description

See rome#4747 for some context.

biome lint --summary should print a summary which allows figuring out which rule raised diagnostics and how many.

$ biome lint --summary src

Rule name                          Diagnostics
nursery/useNamingConvention        2509
style/useSingleCaseStatement       2000
...

Checked 657 file(s) in 3s
Skipped 2 file(s)

The summary should avoid unnecessary works (no need to call diagnostic and action on the rules).

We could suggest using --summary when the number of diagnostics exceeds max-diagnostics:

$ rome lint src
...
src/services/types.ts:1121:5 lint/nursery/useNamingConvention ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ This property name should be in camelCase.
  
  > 1121 │     InsertSpaceAfterConstructor?: boolean;
         │     ^^^^^^^^^^^^^^^^^^^^^^^^^^
  
  ℹ The name could be renamed to `insertSpaceAfterConstructor`.


The number of diagnostics exceeds the number allowed by Biome.
Diagnostics not shown: 7564.
Checked 657 file(s) in 3s
Skipped 2 file(s)

Run `biome lint --summary src` to print a summary of the rules that emitted diagnistics.

[ematipico]

How would someone understand which diagnostics are errors and which ones are warnings?

[Conaclos]

The severity is set at the rule level? It could infer which one is an error using the rule name? We could also use a distinct color in the summary? For instance coloring the number f diagnostics in red for errors and orange for warnings.

[ematipico]

The severity of the rules is set at configuration level.

I was trying to figure out if we can come up with a different output, because the proposed one doesn't distinguish between errors and warnings.

So, we should first be on the same page. Diagnostic is a generic term, while error/warning is a specific term.

Colours is a good suggestion, but it won't work in terminals that don't support colors, and in cases where users might need to scrap the output of the CLI.

[ematipico]

@Conaclos question:

Should --summary keep the log that says "Checked 11 file(s) is 4ms"?

[Conaclos]

Should --summary keep the log that says "Checked 11 file(s) is 4ms"?

I don't see any issue to keep it. I added it in the example.

[Conaclos]

By the way, I wonder if we should propose a common feature for both the summary and the structured output proposals. Instead of providing a --summary flag, we could have a --format suumary. In this case, we should omit the header and lines such as Checked 11 file(s) is 4ms. The output could be tab-or space- separated (this composes well with UNIX programs).

For example:

$ biome lint --format=summary src
nursery/useNamingConvention 2509
style/useSingleCaseStatement 2000
...

[ematipico]

What do you think about --report instead?

In the future, I can see something like this:

biome check --report=summary,json

And Biome will emit:

• a summary to stderr
• json to stdout

And even

biome check --report=summary,json,junit --report-to-file

And Biome will:

• a summary to stderr
• json report to file
• junit report to file

[Conaclos]

What do you think about --report instead?

I think it is a better name. --report or --reporter? Not sure.

Have you some use case for allowing several reporters at the same time?

I am not fond of the mix of behavior (reporting on stderr / stdout / file). I think we should choose between stderr or stdout? Maybe stdout?

For a first version, I think we can skip emitting a file. We could later add an option such as --report-file and guess the reporter type based on the file extension (this could not apply for summary, a user could be explicit using the --report option).

[ematipico]

I am not fond of the mix of behavior (reporting on stderr / stdout / file). I think we should choose between stderr or stdout? Maybe stdout?

stderr is used for printing human readable messages, and stdout is used to printing machine readable messages.

We can remove the file for now, it was just a future idea and not related to this issue. Although, reporting on both stream is actually a thing.

[Conaclos]

stderr is used for printing human readable messages, and stdout is used to printing machine readable messages.

You are right. Even if summary is human-readable (at some extent), it should also be machine-readable. So, I think we can stick for stdout :)

[e965]

Saving the report would be a very cool feature! We could organize annotations in our repository, like we do now with the eslint report and this action https://github.com/ataylorme/eslint-annotate-action - it's very convenient

[hverlin]

Is there a plan to eventually have HTML reporter? (like https://eslint.org/docs/latest/use/formatters/#html) or supporting things like https://www.npmjs.com/package/eslint-formatter-gitlab (to be used on GitLab)

[ematipico]

Is there a plan to eventually have HTML reporter? (like eslint.org/docs/latest/use/formatters/#html) or supporting things like npmjs.com/package/eslint-formatter-gitlab (to be used on GitLab)

@hverlin Please use this github discussion instead, or create a new one. We usually use issues for technical discussions around the task at hand.

[ematipico]

What do you think of this UI @Conaclos ?

     Running `target/debug/biome check './packages/@biomejs/js-api/main.ts' './packages/@biomejs/js-api/main2.ts' --reporter=summary --max-diagnostics=100`
Summarised report of diagnostics by file.

▶ ./packages/@biomejs/js-api/main.ts
     The file isn't formatted.

     Some lint rules were triggered

     Rule Name                                                         Diagnostics
     lint/suspicious/noImplicitAnyLet                                  6
     lint/suspicious/noDoubleEquals                                    3
     lint/suspicious/noRedeclare                                       5
     lint/suspicious/noDebugger                                        11

▶ ./packages/@biomejs/js-api/main2.ts
     The file isn't formatted.

     Some lint rules were triggered

     Rule Name                                                         Diagnostics
     lint/suspicious/noImplicitAnyLet                                  6
     lint/suspicious/noDoubleEquals                                    3
     lint/suspicious/noRedeclare                                       5
     lint/suspicious/noDebugger                                        11


Checked 2 files in 25ms. No fixes needed.
Found 54 errors.
check ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Some errors were emitted while running checks.

[ematipico]

The word "Diagnostics" is dimmed, a bug in my code. I plan to rendering as "Rule Name"

[Conaclos]

Pretty nice :) Actually I was thinking of a general summary. However, I can see the interest for a file-based summary. Maybe we could add a general summary at the end?

Also:

• I think we should remove Some lint rules were triggered because doesn't add so much value. We could rename Rule Name to Triggered lint rule.
• I could remove the underline (this draws too much attention).
• We could reduce a bit the spacing between the two columns
• The file isn't formatted. and The file is formatted. are hard to distinguish. I am not sure how this can be improved.
• Is it normal to get an error at the end?

[ematipico]

Maybe we could add a general summary at the end?

Can you be more specific?

Is it normal to get an error at the end?

Yes? There are errors. The rules that were triggered are recommended, and the documents aren't formatted. The screenshot shows that I run biome check

However, I can see the interest for a file-based summary.

Yes, because it was requested in some other discussion. Also, this should work for other commands that aren't necessary just linting.

[mizdra]

I am the author of eslint-interactive. It is a tool that assists in correcting a large number of errors in ESLint. I would like to share my knowledge with you to help you resolve this discussion.

• https://github.com/mizdra/eslint-interactive

When eslint reports many errors, there are usually errors in many files. Therefore, if we summarize the errors by file, the output could be huge. It is not a good idea to summarize errors by file. Also, users often want to turn off rules that produce many errors. I think it would be nice to be able to display a summary for each rule to assist with this.

eslint-interactive also outputs the number of fixable problems. It would help users to identify rules that can be easily fixed with eslint --fix. In Biome, I think it would be good to output the number of safe fixes and unsafe fixes.

[Conaclos]

Can you be more specific?

▶ ./packages/@biomejs/js-api/main.ts
  The file isn't formatted.

  Triggered lint rule                                   Diagnostics
  lint/suspicious/noImplicitAnyLet                      3

▶ ./packages/@biomejs/js-api/main2.ts
  The file isn't formatted.

  Triggered lint rule                                   Diagnostics
  lint/suspicious/noImplicitAnyLet                      2
  lint/suspicious/noDoubleEquals                        3

▶ General summary
  Some files arn't formatted.

  Triggered lint rule                                   Diagnostics
  lint/suspicious/noImplicitAnyLet                      5
  lint/suspicious/noDoubleEquals                        3

When eslint reports many errors, there are usually errors in many files. Therefore, if we summarize the errors by file, the output could be huge. It is not a good idea to summarize errors by file. Also, users often want to turn off rules that produce many errors. I think it would be nice to be able to display a summary for each rule to assist with this.

Yes this was my first intention for the summary reporter: displaying how much a rule is triggered to assist the dev in enabling/disabling rules.

However, Biome is not currently able to output a summary for every file, this is what ESlint is doing by default. Maybe we should provide two reporters? summary and file-summary?

[ematipico]

I think something is missing here. The idea is to have --summary available for each command (check does linting too), so other than linting we should think about the other commands and how to report them.

I think there's too much focus on the "lint rule", but the focus should be on diagnostics.

[ematipico]

OK, I believe I landed something nice to see and informative, and that makes sense.

Formatter and Organize imports report the files that require changes, while linting groups everything by diagnostic category. We also break down errors, warnings, and information (this is for the near future).

The reason why we break down errors/warnings/infos is because a rule can be downgraded in different files using overrides, so we need to take that into account.