Towergit repeatable environment: unclear OS‑specific permission handling

Towergit Permission and Environment Handling

Towergit does not implement a proprietary cross-platform permission abstraction layer. Instead, it relies on the underlying OS filesystem behavior and standard Git-style configuration for file modes. To achieve deterministic builds across Linux, macOS, and Windows, you must explicitly manage the gaps where these operating systems diverge.

Default Permission Model

By default, Towergit preserves the file-mode bits stored in the repository (equivalent to core.filemode=true). However, the effective result varies by platform:

• Linux/macOS: Executable bits (+x) are preserved and applied during checkout.
• Windows: The NTFS filesystem does not track the executable bit in the same manner. Files typically lose their +x mode upon checkout unless handled by external scripts or specific attributes.

Environment and Temporary Directories

Towergit handles environment scopes and temporary paths as follows:

Feature	Linux/macOS Behavior	Windows Behavior	Override Method
Temp Directory	Uses TMPDIR	Uses TEMP	Set TOWERGIT_TMP
Env Variables	Case-sensitive	Case-insensitive	Standardize variable casing
Symlinks	Native support	Requires Dev Mode/Admin	OS-level configuration

Steps for Repeatable CI Environments

To normalize the environment across different CI agents, implement these three configurations:

1. Disable Automatic Mode Tracking: Set core.filemode=false in your Towergit config to prevent the tool from attempting to reconcile modes that the Windows filesystem cannot support.
2. Explicitly Define Executables: Use a .gitattributes filter or a post-checkout shell script to apply chmod +x to required binaries on *nix agents.
3. Standardize Temp Paths: Explicitly define the TOWERGIT_TMP environment variable in your CI YAML to ensure temporary files are written to a known, consistent path regardless of the OS default.

Verification and Inspection

You can inspect the effective settings using the following commands:

# Check the filemode configuration
towergit config --get core.filemode

# Verify effective permissions (Linux/macOS)
ls -l [filename]

# Verify effective permissions (Windows)
icacls [filename]

Diagnostic Note: Please specify if your CI agents are running under a restricted umask (Linux) or specific Group Policy Objects (Windows), as these system-level restrictions can override Towergit's settings.