Revapi Text Reporter

Super simple Revapi reporter outputting a textual representation of the differences to a file or on standard output. Takes Freemarker templates for formatting the output.

Extension: revapi.reporter.text

This extension is used as a basic means of outputting the results of analysis as text to some file or standard output.

The format of the text can be configured using a FreeMarker template.


Revapi needs to be configured to use this extension, it is not present by default. In case of maven plugin, you need to add the extension as a dependency of the maven plugin like so:

          ... configure the extension here ...

Sample Configuration

    "extension": "revapi.reporter.text",
    "configuration": {
      "minSeverity": "POTENTIALLY_BREAKING",
      "output" : "out",
      "template": "my-template.ftl",
      "append": false



The minimum severity of problems that will be included in the output. If not specified, defaults to POTENTIALLY_BREAKING. Possible values are NON_BREAKING, POTENTIALLY_BREAKING and BREAKING.


The path to the output file. Two special values are recongized: out (which is the default value of this property) and err which represent standard output or standard error output respectively.


A relative path to a FreeMarker template to format the output with. If not specified a built-in simple template is used.


Whether to append to the chosen output or whether to overwrite it (doesn’t make sense for standard (error) output). The default value is false meaning the output file will be overwritten if it already exists.

Example Template

This is actually the default template used by the extension if you don’t configure your own template.

Old API: <#list analysis.oldApi.archives as archive>${}<#sep>, </#list> (1)
New API: <#list analysis.newApi.archives as archive>${}<#sep>, </#list>
<#list reports as report> (2)
old: ${report.oldElement!"<none>"}
new: ${report.newElement!"<none>"}
<#list report.differences as diff>
${diff.code}<#if diff.description??>: ${diff.description}</#if>
<#list diff.classification?keys as compat>${compat}: ${diff.classification?api.get(compat)}<#sep>, </#list> (3)

  1. The analysis configuration is made available in the analysis variable which is an object with type AnalysisContext.

  2. The results of the analysis are made available to the template in the reports variable which is a list of Report objects.

  3. The classification map of a difference uses an enum as a key. To be able to access the values by keys, one has to use the ?api construct and use the native method to access the value. Using classification[compat] is not possible in the example above. This is a limitation of FreeMarker.

FreeMarker Configuration

If you’re going to use your custom template, you will need to how the FreeMarker configuration used for rendering the template.

  • The compatibility level is set to version 2.3.23.

  • The default object wrapper is used and is configured to expose public fields in addition to bean properties.

  • The API built-ins are enabled (i.e. you can use ?api to access the methods of the underlying object).

  • There are 2 template loaders:

    • for templates from /META-INF using the classloader of the extension,

    • for templates anywhere on the filesystem (either relative to the current path or using an absolute path) (note that this is not the default FreeMarker’s FileTemplateLoader which enforces some security restrictions useful in web application environment but which are not desirable in our usecase).

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