add pre-commit to dependency and contributing guideline

.github/PULL_REQUEST_TEMPLATE.md

@@ -6,6 +6,7 @@
 
 - [ ] Fix #xxxx
 - [ ] Pass Codacy code review (green)
+- [ ] Pass Pre-commit check (green)
 - [ ] Pass Circle CI test (green)
 - [ ] Make sure that your code follows our style. Use the other functions/files as a basis.
 - [ ] If modifying functionality, describe changes to function behavior and arguments in a comment below the function declaration.

docs/CONTRIBUTING.md

@@ -35,6 +35,10 @@ is a great starting point if you are new to version control.
    - `upstream`, which refers to the `insarlab` repository
    - `origin`, which refers to your personal fork
 
++ Setting up `pre-commit` within `MintPy` directory:
+   - Run `pre-commit sample-config` to generate a very basic configuration (`.pre-commit-config.yaml`).
+   - Run `pre-commit install` to set up the git hook scripts, so that `pre-commit` will run automatically on git commit ([https://pre-commit.com/](https://pre-commit.com/)).
+
 #### 2. Develop your contribution: ####
 
 + **Open an [issue](https://github.com/insarlab/MintPy/issues) first** if you plan to introduce a new feature or to change funcationality, we may have easier ways to help you implement it. If there is already an issue that matches your idea, leave a comment there instead to let us know what you plan to do. For bug fixes, documentation updates, etc., this is generally not necessary.

docs/environment.yml

@@ -15,11 +15,13 @@ dependencies:
   - dask>=1.0
   - dask-jobqueue>=0.3
   - defusedxml
+  - gdal>=3      # for ISCE, ARIA, FRInGE, HyP3, GMTSAR users
   - h5py
   - joblib
   - lxml
   - matplotlib
   - numpy
+  - pre-commit   # for developers
   - pyaps3>=0.3
   - pykml>=0.2
   - pyproj
@@ -28,5 +30,3 @@ dependencies:
   - rich
   - scikit-image
   - scipy
-  # for ISCE, ARIA, FRInGE, HyP3, GMTSAR
-  - gdal>=3

mintpy/utils/ptime.py

@@ -337,6 +337,8 @@ def read_date_txt(date_file):
         # read text file
         with open(date_file) as f:
             date_list = f.read().splitlines()
+        # ignore invalid lines, e.g. empty
+        date_list = [x for x in date_list if x]
 
         # format
         date_list = sorted(yyyymmdd(date_list))

mintpy/utils/readfile.py

@@ -1308,7 +1308,7 @@ def read_template(fname, delimiter='=', skip_chars=None):
             # skip certain characters by replacing them with empty str
             if skip_chars:
                 for skip_char in skip_chars:
-                    value.replace(skip_char, '')
+                    value = value.replace(skip_char, '')
 
             if value != '':
                 template[key] = value

requirements.txt

@@ -10,11 +10,13 @@ cvxopt
 dask>=1.0
 dask-jobqueue>=0.3
 defusedxml
+# gdal>=3     # for ISCE, ARIA, FRInGE, HyP3, GMTSAR users
 h5py
 joblib
 lxml
 matplotlib
 numpy
+pre-commit    # for developers
 pyaps3>=0.3
 pykml>=0.2
 pyproj
@@ -23,5 +25,3 @@ pysolid
 rich
 scikit-image
 scipy
-# for ISCE, ARIA, FRInGE, HyP3, GMTSAR
-# gdal>=3

setup.py

@@ -62,6 +62,7 @@
         "lxml",
         "matplotlib",
         "numpy",
+        "pre-commit",  # for developers
         "pyaps3>=0.3",
         "pykml>=0.2",
         "pyproj",