Profile file changes

Resolves a ~/ or ~ followed by the file system's default path separator at the start of the path by checking, in order, $HOME, $USERPROFILE (Windows only), $HOMEDRIVE, $HOMEPATH (Windows only), and then the user.home system property.

Looks for the AWS_SHARED_CREDENTIALS_FILE environment variable instead of AWS_CREDENTIAL_PROFILES_FILE.

Silently drops profile definitions in configuration files without the word profile at the beginning of the profile name.

Silently drops profile definitions that do not consist of alphanumeric, underscore or dash characters (after the leading profile word has been removed for configuration files).

Merges settings of profile definitions duplicated within the same file.

Merges settings of profile definitions duplicated in both the configuration and credentials files.

Does NOT merge settings if both [profile foo] and [foo] are found in the same file.

Uses settings in [profile foo] if both [profile foo] and [foo] are found in the configuration file.

Uses the value of the last duplicated setting in the same file and profile.

Recognizes both ; and # for defining a comment.

Recognizes ; and # in profile definitions to define a comment, even if the characters are adjacent to the closing bracket.

Recognizes ; and # to define a comment only in setting values only if they are preceded by whitespace.

Recognizes ; and # and all following content in setting values if they are not preceded by whitespace.

Considers role-based credentials the highest-priority credentials. The 2.x SDK always uses role-based credentials if the user specifies the role_arn property.

Considers session-based credentials the second-highest-priority credentials. The 2.x SDK always uses session-based credentials if role-based credentials were not used and the user specifies the aws_access_key_id and aws_session_token properties.

Uses basic credentials if role-based and session-based credentials are not used and the user specified the aws_access_key_id property.