generator-jhipster: New project (6.5.1) w/ postgresql, liquibase:diff won't find FixedPostgreSQL95Dialect and liquibase:diff changelog output fails to execute

Overview of the issue

In a clean, new, project, using postgresql, liquibase won’t find the custom jhipster postgresql driver dialect, and switching that driver results in a liquibase:diff output that fails to run.

This is partially similar to #10885, created earlier today.

Motivation for or Use Case

I expect a newly created project to output no changes with liquibase:diff, and also expect the custom jhipster postgresql dialect driver to be found.

Reproduce the error

I created a repository each step in a commit: https://github.com/nuba/bug-report-jhipster-liquibase

Error messages are

[ERROR] Failed to execute goal org.liquibase:liquibase-maven-plugin:3.6.3:diff (default-cli) on project jhipster: Error setting up or running Liquibase: liquibase.exception.UnexpectedLiquibaseException: liquibase.exception.DatabaseException: java.lang.ClassNotFoundException: io.github.jhipster.domain.util.FixedPostgreSQL95Dialect -> [Help 1]

And

[ERROR] Failed to execute goal org.liquibase:liquibase-maven-plugin:3.6.3:update (default-cli) on project jhipster: Error setting up or running Liquibase: Migration failed for change set config/liquibase/changelog/20191205215152_changelog.xml::1575582718315-1::nuba (generated):
[ERROR]      Reason: liquibase.exception.DatabaseException: ERROR: constraint "uc_jhi_useremail_col" of relation "jhi_user" does not exist [Failed SQL: ALTER TABLE jhi_user DROP CONSTRAINT UC_JHI_USEREMAIL_COL]
[ERROR] -> [Help 1]

Here is the table definition in postgres

bugreport=# \d jhi_user;
                              Table "public.jhi_user"
       Column       |            Type             | Collation | Nullable | Default 
--------------------+-----------------------------+-----------+----------+---------
 id                 | bigint                      |           | not null | 
 login              | character varying(50)       |           | not null | 
 password_hash      | character varying(60)       |           | not null | 
 first_name         | character varying(50)       |           |          | 
 last_name          | character varying(50)       |           |          | 
 email              | character varying(191)      |           |          | 
 image_url          | character varying(256)      |           |          | 
 activated          | boolean                     |           | not null | 
 lang_key           | character varying(10)       |           |          | 
 activation_key     | character varying(20)       |           |          | 
 reset_key          | character varying(20)       |           |          | 
 created_by         | character varying(50)       |           | not null | 
 created_date       | timestamp without time zone |           |          | 
 reset_date         | timestamp without time zone |           |          | 
 last_modified_by   | character varying(50)       |           |          | 
 last_modified_date | timestamp without time zone |           |          | 
Indexes:
    "jhi_user_pkey" PRIMARY KEY, btree (id)
    "ux_user_email" UNIQUE CONSTRAINT, btree (email)
    "ux_user_login" UNIQUE CONSTRAINT, btree (login)
Referenced by:
    TABLE "jhi_user_authority" CONSTRAINT "fk_user_id" FOREIGN KEY (user_id) REFERENCES jhi_user(id)

Related issues

Yes, #10885 mentions the diff output, but not the driver issue.

JHipster Version(s)

6.5.1

JHipster configuration

INFO! Using JHipster version installed locally in current project’s node_modules INFO! Executing jhipster:info INFO! Options: from-cli: true

JHipster Version(s)

jhipster@0.0.0 /home/nuba/IdeaProjects/bug-reports/jhipster-liquibase
└── generator-jhipster@6.5.1 

JHipster configuration, a .yo-rc.json file generated in the root folder

{
  "generator-jhipster": {
    "promptValues": {
      "packageName": "bug.report"
    },
    "jhipsterVersion": "6.5.1",
    "applicationType": "monolith",
    "baseName": "jhipster",
    "packageName": "bug.report",
    "packageFolder": "bug/report",
    "serverPort": "8080",
    "authenticationType": "jwt",
    "cacheProvider": "no",
    "websocket": false,
    "databaseType": "sql",
    "devDatabaseType": "postgresql",
    "prodDatabaseType": "postgresql",
    "searchEngine": false,
    "messageBroker": false,
    "serviceDiscoveryType": false,
    "buildTool": "maven",
    "enableSwaggerCodegen": false,
    "jwtSecretKey": "bXktc2VjcmV0LXRva2VuLXRvLWNoYW5nZS1pbi1wcm9kdWN0aW9uLWFuZC10by1rZWVwLWluLWEtc2VjdXJlLXBsYWNl",
    "embeddableLaunchScript": false,
    "useSass": true,
    "clientPackageManager": "npm",
    "skipClient": true,
    "testFrameworks": [],
    "jhiPrefix": "jhi",
    "entitySuffix": "",
    "dtoSuffix": "DTO",
    "otherModules": [],
    "enableTranslation": false,
    "blueprints": []
  }
}

JDL for the Entity configuration(s) entityName.json files generated in the .jhipster directory

Environment and Tools

openjdk version “11.0.5-ea” 2019-10-15 OpenJDK Runtime Environment (build 11.0.5-ea+10-post-Ubuntu-0ubuntu1) OpenJDK 64-Bit Server VM (build 11.0.5-ea+10-post-Ubuntu-0ubuntu1, mixed mode, sharing)

git version 2.20.1

node: v12.13.1

npm: 6.13.1

yeoman: 3.1.1

Docker version 19.03.2, build 6a30dfca03

INFO! Congratulations, JHipster execution is complete!

Entity configuration(s) entityName.json files generated in the .jhipster directory

No entity has been created. The app had just been generated.

Browsers and Operating System

Ubuntu 19.10

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